Noise reduction device for range hood, range hood and control method thereof

Abstract

The present invention relates to a noise reduction device for a range hood, a range hood, and a control method thereof. The noise reduction device comprises: a first noise reduction plate having first noise reduction holes distributed thereon; and a second noise reduction plate driven by a driving mechanism to move closer to or farther from the first noise reduction plate. The second noise reduction plate has second noise reduction holes formed at positions corresponding to the first noise reduction holes. Each second noise reduction hole on the second noise reduction plate is connected to the corresponding first noise reduction hole on the first noise reduction plate via a conduit assembly with adjustable length. When the first noise reduction plate of the noise reduction device moves to different positions relative to the second noise reduction plate, the first noise reduction holes of the first noise reduction plate and the second noise reduction holes of the second noise reduction plate form "through holes" of different depths through the conduit assembly. The "through holes" of different depths have different noise reduction effects on noises of different frequencies. Thus, the purpose of matching noise reduction to noises generated under different working conditions can be achieved, thereby ensuring the noise reduction effect.

Description

Technical Field

[0001] The present invention relates to the technical field of range hoods, and in particular to a noise reduction device for a range hood, a range hood and a control method thereof. Background Art

[0002] Range hoods have become an indispensable kitchen appliance in modern homes. The noise generated during operation has always been a serious problem for users. Noise is mainly categorized as aerodynamic noise, mechanical noise, and electromagnetic noise. Mechanical noise is generated by fixed vibrations, primarily the vibrations of the volute, impeller, motor, fan, and housing. Electromagnetic noise is caused by the pulsation of the magnetic field within the motor, which causes vibrations in electrical components. The most important aerodynamic noise includes rotational noise and eddy current noise. Rotational noise is caused by the impeller's rotating blades striking the surrounding gas, causing pressure pulsations in the surrounding gas. Eddy current noise is caused by air vortices or sudden pressure changes in the flow channel, causing air disturbances.

[0003] In order to reduce the above-mentioned aerodynamic noise, range hoods generally adopt passive noise reduction by placing sound-absorbing cotton in the air duct and the volute air inlet. However, the sound-absorbing cotton will occupy the air duct space and affect the performance of the range hood such as air volume and air pressure. On the other hand, after the range hood has been used for a period of time, the sound-absorbing cotton will affect the noise reduction effect due to oil absorption. In particular, the sound-absorbing cotton is only effective in reducing noise in a specific frequency band. If the main frequency of the noise changes, the sound-absorbing cotton cannot be adjusted adaptively.

[0004] To this end, the Chinese invention patent application with application number CN202110475152.7 (application publication number CN113203111A) discloses a range hood, comprising an air intake assembly, a power unit for being arranged above a suspended ceiling, and a connecting pipe connecting the air intake assembly and the power unit to fluid, a noise reduction assembly being provided between the connecting pipe and the power unit, the noise reduction assembly comprising a first housing, the first housing comprising a front side wall located at the front side, the front side wall comprising at least a curved section located at the upper portion, the curved section gradually tilting downward and backward from the upper end of the front side wall into a smoothly curved shape. A noise reduction deflector is also provided in the first housing, the noise reduction deflector being provided on the curved section of the front side wall, and a noise reduction hole being provided on the noise reduction deflector. The first housing also comprises a rear side wall located at the rear side, a third sound absorbing member being provided on the rear side wall, the third sound absorbing member being capable of absorbing the noise reflected by the noise reduction deflector and transmitted downward from the power unit. Among them, the third sound-absorbing member has at least two areas with different noise absorption frequencies. The noise reduction deflector is rotatably connected to the front side wall through a rotating shaft. Driven by the driving mechanism, the angle of the noise reduction deflector is adjustable, so that the noise of the power unit can be reflected to the area of the third sound-absorbing member corresponding to the noise absorption frequency, thereby achieving targeted noise reduction.

[0005] The range hood in the above patent application also has certain shortcomings. The method of reflecting noise to areas of different noise absorption frequencies on the sound-absorbing component by adjusting the inclination angle of the noise reduction deflector will cause the noise reduction deflector to occupy a certain amount of air duct space. In particular, when the angle of inclination of the noise reduction deflector toward the inside of the air duct is large, it will affect the smooth air intake of the fan system, resulting in limited air volume, and may cause new noise to be generated due to deviation from the optimal deflection effect. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a noise reduction device for range hoods in response to the current status of the existing technology, which can not only avoid affecting the air intake volume due to occupying the space in the air duct, but also match the noise generated under different working conditions to reduce the noise.

[0007] The second technical problem to be solved by the present invention is to provide a range hood that, in response to the current status of the existing technology, can avoid affecting the air intake volume due to occupying space in the air duct and can also match the noise generated under different working conditions to reduce the noise.

[0008] The third technical problem to be solved by the present invention is to provide a control method for a range hood that can match the noise generated under different working conditions with the current status of the existing technology.

[0009] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is:

[0010] A noise reduction device for a range hood, comprising:

[0011] a first noise reduction plate having first noise reduction holes distributed thereon;

[0012] The second noise reduction plate is arranged opposite to the first noise reduction plate and is driven by a driving mechanism to move closer to or farther away from the first noise reduction plate. Second noise reduction holes are opened on the second noise reduction plate at positions corresponding to the first noise reduction holes. Each of the second noise reduction holes on the second noise reduction plate is connected to the corresponding first noise reduction hole on the first noise reduction plate through a conduit assembly with adjustable length.

[0013] The catheter assembly can adopt a flexible tube with retractable length (such as a bellows), or it can adopt two sleeve tube structures that can be sleeved together and slide in the axial direction. In order to ensure the accuracy of position adjustment between the second noise reduction plate and the second noise reduction plate, each first noise reduction hole on the first noise reduction plate is provided with a first catheter extending toward the second noise reduction plate, and each corresponding second noise reduction hole on the second noise reduction plate is provided with a second catheter extending toward the first noise reduction plate and can be sleeved together with the corresponding first catheter. The first catheter and the second catheter together constitute the catheter assembly.

[0014] The structure in which the first and second ducts are sleeved and matched with each other also plays a good guiding role, so that the second noise reduction plate can move stably along the axial direction of the second duct, and there will be no problem of lateral offset between the second noise reduction plate and the first noise reduction plate, thereby improving the accuracy of position adjustment between the second noise reduction plate and the second noise reduction plate, and ensuring the noise reduction effect.

[0015] In order to ensure the noise reduction effect, the second conduit is sleeved outside the first conduit, and the inner peripheral wall of the second conduit is in sealing contact with the outer peripheral wall of the first conduit.

[0016] The driving mechanism can adopt a motion device that cooperates with a driving motor and a connecting rod transmission mechanism, a gear rack transmission mechanism or a screw slider transmission assembly. In order to ensure the accuracy of the displacement adjustment of the second noise reduction plate, the driving mechanism includes a driving motor and a screw slider transmission assembly. The output shaft of the driving motor is connected to the second noise reduction plate through the screw slider transmission assembly.

[0017] In order to achieve the purpose of targeted noise reduction of broadband noise and further improve the overall noise reduction effect of the noise reduction device, it also includes:

[0018] An auxiliary noise reduction plate is slidingly arranged on the side of the second noise reduction plate away from the first noise reduction plate along the plane where the second noise reduction plate is located, and is provided with third noise reduction holes that can be connected with the second noise reduction holes on the second noise reduction plate. The auxiliary noise reduction plate can block at least part of the second noise reduction holes on the second noise reduction plate when sliding relative to the second noise reduction plate.

[0019] Since the adjustable distance range of the auxiliary noise reduction plate relative to the second noise reduction plate is limited, in order to enable the auxiliary noise reduction plate to achieve different porosity adjustments within a smaller moving range, the auxiliary noise reduction plate is arranged on the second noise reduction plate in a manner that allows it to slide linearly relative to the second noise reduction plate. The moving direction of the auxiliary noise reduction plate relative to the second noise reduction plate is recorded as a first linear direction;

[0020] Each third noise reduction hole on the auxiliary noise reduction plate includes at least a first hole and a second hole. The size of the first hole in the first straight line direction is different from the size of the second hole in the first straight line direction. When the auxiliary noise reduction plate moves to different positions relative to the second noise reduction plate, different numbers of third noise reduction holes on the auxiliary noise reduction plate are correspondingly connected to the second noise reduction holes of the second noise reduction plate.

[0021] For the convenience of processing, a row of second noise reduction holes arranged along the first straight line on the second noise reduction plate is recorded as a second noise reduction hole group, and the second noise reduction holes in each second noise reduction hole group have the same size;

[0022] A row of third noise reduction holes arranged along the first straight line on the auxiliary noise reduction plate is recorded as a third noise reduction hole group. The sizes of the third noise reduction holes in each third noise reduction hole group are the same. The sizes of the third noise reduction holes in at least two third noise reduction hole groups on the auxiliary noise reduction plate are different. When the auxiliary noise reduction plate moves to different positions relative to the second noise reduction plate, different numbers of third noise reduction hole groups on the auxiliary noise reduction plate are connected to the second noise reduction hole groups of the second noise reduction plate. In a preferred embodiment, the sizes of the third noise reduction holes of two adjacent third noise reduction hole groups on the auxiliary noise reduction plate are different. The above structural design also ensures that when the auxiliary noise reduction plate moves to different positions, the third noise reduction holes on it that are connected to the second noise reduction holes on the second noise reduction plate are arranged in sequence along the first straight line, thereby ensuring the noise reduction effect.

[0023] In order to achieve stable sliding of the auxiliary noise reduction plate relative to the second noise reduction plate, the second noise reduction plate has a sliding groove extending along the first straight line direction, and the auxiliary noise reduction plate is slidingly constrained in the sliding groove.

[0024] Generally, the movement process of the auxiliary noise reduction plate relative to the second noise reduction plate and the movement process of the second noise reduction plate relative to the first noise reduction plate can be independent, that is, the movement processes of the two can be driven by different driving mechanisms. However, in order to reduce the number of driving mechanisms, reduce costs, and simplify the overall structure of the noise reduction device, it also includes a first box body, which defines a channel for sound propagation. The first noise reduction plate, the second noise reduction plate and the auxiliary noise reduction plate are all arranged in the channel of the first box body, and the first noise reduction plate is fixed relative to the first box body. A swing rod is also provided between the auxiliary noise reduction plate and the first box body. The first end of the swing rod is rotatably connected to the auxiliary noise reduction plate, and the second end is rotatably connected to the first box body. During the movement of the second noise reduction plate relative to the first noise reduction plate, the force is transmitted to the auxiliary noise reduction plate through the swing rod, thereby driving the auxiliary noise reduction plate to move relative to the second noise reduction plate.

[0025] Through experiments, it is verified that the "hole depth" of the noise reduction hole of the noise reduction device (that is, the length of the noise reduction hole along its axial direction, which is related to the distance between the first noise reduction plate and the second noise reduction plate) and the "perforation rate" on the noise reduction plate (that is, the ratio of the total area of the noise reduction holes that pass through the front and back to the area of the noise reduction plate) are different, and the noise reduction effect on noises of different frequencies is different. First of all, the different hole depths have different corresponding sound absorption coefficients. The greater the depth, the better the sound absorption effect on low-frequency noise, and the smaller the depth, the better the sound absorption effect on high-frequency noise. The smaller the perforation rate, the better the sound absorption effect on low-frequency noise. The better, the greater the perforation rate, the better the sound absorption effect of high-frequency noise. In order to make the hole depth adjustment of the noise reduction hole of the noise reduction device and the adjustment of the perforation rate consistent in the noise reduction effect, as an improvement, the second noise reduction plate has at least a first vertical position and a second vertical position during the movement relative to the first noise reduction plate. When the second noise reduction plate is in the first vertical position, the distance between the second noise reduction plate and the first noise reduction plate is recorded as a first distance. When the second noise reduction plate is in the second vertical position, the distance between the second noise reduction plate and the first noise reduction plate is recorded as a second distance. The first distance is smaller than the second distance.

[0026] The auxiliary noise reduction plate has at least a first horizontal position corresponding to the first vertical position of the second noise reduction plate and a second horizontal position corresponding to the second vertical position of the second noise reduction plate during its movement relative to the second noise reduction plate. When the auxiliary noise reduction plate is in the first horizontal position, the number of corresponding connections between the third noise reduction holes on the auxiliary noise reduction plate and the second noise reduction holes on the second noise reduction plate is greater than the number of corresponding connections between the third noise reduction holes on the auxiliary noise reduction plate and the second noise reduction holes on the second noise reduction plate when the auxiliary noise reduction plate is in the second horizontal position.

[0027] The technical solution adopted by the present invention to solve the above-mentioned second technical problem is: a range hood, including a fan device and a smoke collection hood fluidly connected to the fan device, and also including the above-mentioned noise reduction device, which is arranged on the flow path between the fan device and the smoke collection hood, and is arranged adjacent to the fan device.

[0028] Another technical solution adopted by the present invention to solve the above-mentioned second technical problem is: a range hood, comprising a fan device and a smoke collection hood fluidly connected to the fan device, and also comprising the above-mentioned noise reduction device, which is arranged on the flow path between the fan device and the smoke collection hood, and is arranged adjacent to the fan device, the fan device comprises a fan housing and a centrifugal fan arranged in the fan housing, the centrifugal fan has a downward air inlet, the first housing of the noise reduction device is connected to the bottom of the fan housing, the first noise reduction plate is arranged on the inner wall of the first housing, and is inclined from bottom to top toward the position of the air inlet of the centrifugal fan.

[0029] The above-mentioned first noise reduction plate, second noise reduction plate and auxiliary noise reduction plate are all arranged on the first box body to form a modular structure that can be easily installed on the range hood body. During assembly, the corresponding noise reduction plate can be installed on the first box body first, and then the entire module can be installed on the range hood body, which is more convenient and quick.

[0030] In order to realize adaptive adjustment of the noise reduction device according to the noise situation under the current operating condition of the range hood, a noise collection device is also included to collect noise information under the current operating state of the fan device;

[0031] The controller is electrically connected to the driving mechanisms of the noise collection device and the noise reduction device, thereby controlling the operation of the driving mechanisms according to the noise signal transmitted by the noise collection device, and moving the second noise reduction plate and the auxiliary noise reduction plate of the noise reduction device to positions matching the noise signal.

[0032] The present invention solves the third technical problem by adopting a technical solution: a range hood control method, characterized by comprising the following steps:

[0033] S1: The range hood starts, and the fan device runs at the default gear;

[0034] S2. The noise collection device collects noise information under the current operating state of the fan device and transmits the noise signal to the controller, which performs spectrum analysis to obtain the main noise frequency f;

[0035] S3. The controller controls the driving mechanism to move the second noise reduction plate and the auxiliary noise reduction plate to positions that match the main noise frequency f.

[0036] Compared with the prior art, the present invention has the following advantages: when the first noise reduction plate of the noise reduction device is moved to different positions relative to the second noise reduction plate, the first noise reduction hole of the first noise reduction plate and the second noise reduction hole of the second noise reduction plate, formed through the duct assembly, have different depths of "through holes." These "through holes" of different depths have different noise reduction effects on noise of different frequencies. Therefore, by adjusting the relative positions of the two noise reduction plates, the purpose of matching noise reduction to noise generated under different working conditions can be achieved, thereby ensuring the noise reduction effect. Furthermore, because the second noise reduction plate of the noise reduction device is only movable and adjusted in a straight line perpendicular to the first noise reduction plate, it does not occupy excessive space in the air duct and affect the air intake volume, as in the prior art, as the deflected noise reduction plates do. In a preferred embodiment, an auxiliary noise reduction plate is also provided on the second noise reduction plate, which can block at least part of the second noise reduction hole on the second noise reduction plate during the sliding process relative to the second noise reduction plate, thereby realizing the adjustment of the perforation rate of the noise reduction hole on the noise reduction device. In this way, the noise reduction effect of the noise reduction device can be further improved by dual adjustment of the depth of the "through hole" of the noise reduction device and the perforation rate of the noise reduction hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the three-dimensional structure of the fan device and the noise reduction device installed together according to an embodiment of the present invention;

[0038] Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure after the bottom is turned over;

[0039] Figure 3 for Figure 2 Cross-sectional view at AA in the middle;

[0040] Figure 4 for Figure 3 Cross-sectional view at AA in the middle;

[0041] Figure 5 for Figure 1 A schematic diagram of a three-dimensional structure in which the fan device and the noise reduction device are separated;

[0042] Figure 6 Schematic diagram of the three-dimensional structure of the noise reduction device according to an embodiment of the present invention;

[0043] Figure 7 A vertical cross-sectional view of the noise reduction device according to an embodiment of the present invention taken along the front-to-back direction (the distance between the first noise reduction plate and the second noise reduction plate is small);

[0044] Figure 8 A vertical cross-sectional view of the noise reduction device according to an embodiment of the present invention taken along the front-to-back direction (the spacing between the first noise reduction plate and the second noise reduction plate is moderate);

[0045] Figure 9 A vertical cross-sectional view of the noise reduction device according to an embodiment of the present invention taken along the front-to-back direction (the distance between the first noise reduction plate and the second noise reduction plate is relatively large);

[0046] Figure 10 Schematic diagram of the three-dimensional structure of the auxiliary noise reduction plate according to an embodiment of the present invention;

[0047] Figure 11 is a schematic diagram of the three-dimensional structure of a range hood according to an embodiment of the present invention;

[0048] Figure 12 This is a diagram showing the sound absorption effect of the through holes of the micro-perforated plate at different hole depths for noises of different frequencies;

[0049] Figure 13 This is a diagram showing the sound absorption effect of the through holes of the micro-perforated plate at different perforation rates for noises of different frequencies. DETAILED DESCRIPTION

[0050] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0051] In the present specification and claims, directional terms such as "front," "back," "up," "down," "left," "right," "side," "top," and "bottom" are used to describe various exemplary structural parts and components of the present invention. However, these terms are used herein for convenience of description only and are based on the exemplary orientations shown in the accompanying drawings. Because the embodiments disclosed herein can be arranged in various orientations, these directional terms are intended for illustrative purposes only and should not be construed as limiting. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0052] See also Figures 1-11 A noise reduction device for a range hood includes a first box body 40, a first noise reduction plate 11, a second noise reduction plate 21, an auxiliary noise reduction plate 31 and a driving device.

[0053] The first housing 40 has a first interface 41 and a second interface 42 that are opposed to each other in upper and lower positions. The opening area of the first interface 41 is larger than that of the second interface 42. The second interface 42 is located at the bottom rear side of the first interface 41. The interior of the first housing 40 forms a channel for sound propagation. The first noise reduction plate 11, the second noise reduction plate 21, the auxiliary noise reduction plate 31, and the drive device are all disposed within the first housing 40.

[0054] See also Figure 7, the first noise reduction plate 11 and the first box body 40 are integrally formed. The first noise reduction plate 11 is arranged on the rear side wall of the first box body 40, and is inclined forward from bottom to top. The first noise reduction plate 11 is distributed with first noise reduction holes 12, wherein the first noise reduction holes 12 are all circular holes with the same aperture, and the first noise reduction holes 12 are arranged in sequence along the left-right direction. A row of first noise reduction holes 12 arranged in sequence along the left-right direction is recorded as a first noise reduction hole group. The back side of the first noise reduction plate 11 has a first conduit 13 extending outward (i.e., backward) in a direction perpendicular to the plane where the first noise reduction plate 11 is located, corresponding to each first noise reduction hole 12. The inner diameter of the first conduit 13 is basically the same as the aperture of the first noise reduction hole 12.

[0055] The second noise reduction plate 21 is located on the back side of the first noise reduction plate 11, that is, on the upper side of the first noise reduction plate 11, and can be driven by a driving mechanism to move closer to or farther away from the first noise reduction plate 11. The second noise reduction plate 21 is arranged opposite to the first noise reduction plate 11, that is, the planes on which the two are located are parallel to each other. Second noise reduction holes 22 are distributed on the second noise reduction plate 21, wherein each second noise reduction hole 22 on the second noise reduction plate 21 corresponds one-to-one to each first noise reduction hole 12 on the first noise reduction plate 11. The second noise reduction plate 21 has a second conduit 23 extending toward the first noise reduction plate 11 at a position corresponding to each second noise reduction hole 22 on the side facing the first noise reduction plate 11, wherein each second conduit 23 is correspondingly sleeved on the outside of the first conduit 13, and the inner diameter of the second conduit 23 matches the outer diameter of the first conduit 13, thereby achieving a sealed contact between the inner circumferential wall of the second conduit 23 and the outer circumferential wall of the first conduit 13. The structure in which the first conduit 13 and the second conduit 23 are fitted together also plays a good guiding role, so that the second noise reduction plate 21 can move stably along the axis of the second conduit 23 without the problem of lateral offset between the second noise reduction plate 21 and the first noise reduction plate 11, thereby improving the accuracy of position adjustment between the second noise reduction plate 21 and the second noise reduction plate 21.

[0056] See also Figure 6 , the inner wall of the first box body 40 is also provided with a fixing plate 43, which is used to fix the driving mechanism. The driving mechanism of this embodiment includes a driving motor 51 and a screw slider transmission assembly. Among them, the screw slider transmission assembly includes a screw 52 and a slider 53 threadedly connected to the screw 52, and the slider is connected to the second noise reduction plate 21. The driving motor 51 is fixed to the fixing plate 43, and its power output shaft is coaxially connected to the screw 52. When the driving motor 51 is in motion, the second noise reduction plate 21 can be driven to move up and down relative to the first noise reduction plate through the screw slider transmission assembly. Figure 4 The drive mechanism comprises two sets of left and right drive mechanisms, one on each side of the first housing 40 and the other on the left and right sides, corresponding to the left and right ends of the second noise reduction plate 21. The two drive motors 51 can operate synchronously, thereby ensuring the stability of the vertical movement of the second noise reduction plate 21 relative to the first noise reduction plate 11.

[0057] The auxiliary noise reduction plate 31 is arranged on the side of the second noise reduction plate 21 away from the first noise reduction plate 11, that is, on the upper side of the second noise reduction plate 21. The auxiliary noise reduction plate 31 and the second noise reduction plate 21 are attached to each other and can be moved in the left and right directions (that is, Figure 6 The auxiliary noise reduction plate 31 is configured to reciprocate in the first linear direction A1). Specifically, the front and rear sides of the second noise reduction plate 21 are each provided with a slide groove 24 extending in the left-right direction. The front and rear edges of the auxiliary noise reduction plate 31 are respectively slidably restrained in the two slide grooves 24 of the second noise reduction plate 21. The auxiliary noise reduction plate 31 is provided with third noise reduction holes 32. The number of the third noise reduction holes 32 matches the number of the second noise reduction holes 22 on the second noise reduction plate 21, and they correspond one-to-one.

[0058] A row of second noise reduction holes 22 arranged along the first straight line on the second noise reduction plate 21 is referred to as a second noise reduction hole group, and the second noise reduction holes 22 in each second noise reduction hole group have the same size. Similarly, a row of third noise reduction holes 32 arranged along the first straight line on the auxiliary noise reduction plate 31 is referred to as a third noise reduction hole group, and the third noise reduction holes 32 in each third noise reduction hole group have the same size. The auxiliary noise reduction plate 31 has at least two third noise reduction hole groups, and the third noise reduction holes 32 in the two groups have different sizes in the first straight line direction. For details, see Figure 10 , three groups of third noise reduction hole groups with different sizes are shown on the auxiliary noise reduction plate 31, namely the third noise reduction hole group 32s, the third noise reduction hole group 32n and the third noise reduction hole group 32m. The three groups of third noise reduction hole groups are arranged adjacent to each other (that is, arranged in sequence along the width direction of the auxiliary noise reduction plate), wherein the third noise reduction holes 32c in the third noise reduction hole group 32m and the third noise reduction holes 32b in the second noise reduction hole group 32n are both waist-shaped holes extending along the first straight line direction, and the length dimension of the third noise reduction holes 32c is greater than the length dimension of the third noise reduction holes 32b, and the third noise reduction holes 32a in the third noise reduction hole group 32s are circular holes, and their size is smaller than that of the third noise reduction holes 32b.

[0059] When the auxiliary noise reduction plate 31 moves to different positions relative to the second noise reduction plate 21, different numbers (different groups) of third noise reduction hole groups on the auxiliary noise reduction plate 31 are connected to the second noise reduction hole groups of the second noise reduction plate 21. Figure 7 In the position state, the third noise reduction holes 32 corresponding to the three groups of third noise reduction hole groups of different sizes on the auxiliary noise reduction plate 31 (i.e., the third noise reduction hole group 32s, the third noise reduction hole group 32n, and the third noise reduction hole group 32m) are all connected to the second noise reduction holes 22 corresponding to the second noise reduction hole group on the second noise reduction plate. Figure 8In the position state, the third noise reduction holes 32 corresponding to the two third noise reduction hole groups (i.e., the third noise reduction hole group 32n and the third noise reduction hole group 32m) of different sizes on the auxiliary noise reduction plate 31 are both connected to the second noise reduction holes 22 corresponding to the second noise reduction hole group on the second noise reduction plate. Figure 9 In the current position, only one third noise reduction hole group (i.e., the third noise reduction hole group 32m) on the auxiliary noise reduction plate 31 corresponds to the third noise reduction holes 32, which are all connected to the second noise reduction holes 22 corresponding to the second noise reduction hole group on the second noise reduction plate. Figures 7 to 9 By comparison, it can be seen that when the auxiliary noise reduction plate 31 moves to different positions, the number of through holes in the entire noise reduction device (that is, the first noise reduction hole 12, the second noise reduction hole 22 and the third noise reduction hole 32 are correspondingly connected) is different, that is, the perforation rate is different.

[0060] When the second noise reduction plate 21 moves to different positions relative to the first noise reduction plate 11, the "hole depth" of the through hole of the entire noise reduction device (that is, the length of the through hole along its axial direction, which is related to the distance between the first noise reduction plate 11 and the second noise reduction plate 21) is different. Figure 7 As shown, the distance between the first noise reduction plate 11 and the second noise reduction plate 21 is the smallest, that is, the "hole depth" of the through hole of the entire noise reduction device (in Figure 7 Indicated by h) is the smallest, such as Figure 8 As shown, the distance between the first noise reduction plate 11 and the second noise reduction plate 21 is moderate, that is, the "hole depth" of the through hole of the entire noise reduction device is moderate, as shown in FIG. Figure 9 As shown, the distance between the first noise reduction plate 11 and the second noise reduction plate 21 is the largest, that is, the "hole depth" of the through hole of the entire noise reduction device is also the largest.

[0061] A swing lever 44 is also provided between the auxiliary noise reduction plate 31 and the fixed plate 43 of the first housing 40. The first end of the swing lever 44 is rotatably connected to a first pin at the end of the auxiliary noise reduction plate 31, and the second end is rotatably connected to a second pin on the fixed plate 43. Both the first and second pins extend parallel to the plane of the auxiliary noise reduction plate 31. During movement of the second noise reduction plate 21 relative to the first noise reduction plate 11, force is transmitted to the auxiliary noise reduction plate 31 via the swing lever 44, thereby driving the auxiliary noise reduction plate 31 to move relative to the second noise reduction plate 21.

[0062] Taking the three different positions of the second noise reduction plate 21 during its movement relative to the first noise reduction plate 11 as an example, the three positions are respectively recorded as the first vertical position, the second vertical position and the third vertical position. When the second noise reduction plate 21 is in the first vertical position, the distance between it and the first noise reduction plate 11 is recorded as the first distance. When the second noise reduction plate 21 is in the second vertical position, the distance between it and the first noise reduction plate 11 is recorded as the second distance. When the second noise reduction plate 21 is in the third vertical position, the distance between it and the first noise reduction plate 11 is recorded as the third distance. Among them, the first distance is smaller than the second distance, and the second distance is smaller than the third distance. Since the horizontal movement process of the auxiliary noise reduction plate 31 is linked with the up and down movement process of the second noise reduction plate 21, the auxiliary noise reduction plate 31 also has three positions during the movement relative to the second noise reduction plate 21, namely, the first horizontal position, the second horizontal position and the third horizontal position. When the second noise reduction plate 21 is in the first vertical position, the auxiliary noise reduction plate 31 is in the first horizontal position; when the second noise reduction plate 21 is in the second vertical position, the auxiliary noise reduction plate 31 is in the second horizontal position; when the second noise reduction plate 21 is in the third vertical position, the auxiliary noise reduction plate 31 is in the third horizontal position. When the auxiliary noise reduction plate 31 is in the first horizontal position, the number of corresponding connections between the third noise reduction holes 32 on it and the second noise reduction holes 22 on the second noise reduction plate 21 is greater than the number of corresponding connections between the third noise reduction holes 32 on the auxiliary noise reduction plate 31 and the second noise reduction holes 22 on the second noise reduction plate 21 when the auxiliary noise reduction plate 31 is in the second horizontal position. When the auxiliary noise reduction plate 31 is in the second horizontal position, the number of corresponding connections between the third noise reduction holes 32 on the auxiliary noise reduction plate 31 and the second noise reduction holes 22 on the second noise reduction plate 21 is greater than the number of corresponding connections between the third noise reduction holes 32 on the auxiliary noise reduction plate 31 and the second noise reduction holes 22 on the second noise reduction plate 21 when the auxiliary noise reduction plate 31 is in the third horizontal position.

[0063] Figure 12 The figure shows the sound absorption effect of the through holes of the micro-perforated plate at different hole depths for noises of different frequencies. Figure 13 The figure shows the sound absorption effect of the through holes of the micro-perforated plate for different frequencies of noise under different perforation rates. The experiment shows that the "hole depth" of the noise reduction hole (through hole) of the noise reduction device (that is, the length of the noise reduction hole along its axial direction) is related to the distance between the first noise reduction plate 11 and the second noise reduction plate 21. Figure 12 In the figure, different hole depths t, i.e. 0.25mm, 0.5mm, 1mm, 2mm) and the "perforation ratio" on the noise reduction plate (i.e. the ratio of the total area of the noise reduction holes that pass through the front and back to the area of the noise reduction plate, are shown. Figure 13The figure shows that different perforation ratios (δ) have different noise reduction effects on noise of different frequencies. First, different through-hole depths correspond to different sound absorption coefficients. The greater the depth, the better the sound absorption effect on low-frequency noise, while the smaller the depth, the better the sound absorption effect on high-frequency noise. Furthermore, the smaller the perforation ratio, the better the sound absorption effect on low-frequency noise, while the larger the perforation ratio, the better the sound absorption effect on high-frequency noise. The influence of these geometric parameters on sound absorption performance can be found in: Jiang Congshuang. Research on Sound Absorption and Noise Reduction of Variable-Section Micro-Perforated Plates [D]. China University of Geosciences (Beijing), 2020. This embodiment effectively improves the noise reduction effect of the noise reduction device by dually adjusting the depth and perforation ratio of the "through-holes" of the noise reduction device.

[0064] The "hole depth" of the through hole of the noise reduction device of this embodiment ranges from 0.2mm to 4mm. The first noise reduction hole 12 and the second noise reduction hole 22 are both circular holes. In order to ensure the noise reduction effect, their apertures are generally less than 1mm. The third noise reduction hole 32a on the third noise reduction plate is also a circular hole, and its aperture is basically the same as the aperture of the first noise reduction hole. The third noise reduction hole 32b and the third noise reduction hole 32c on the third noise reduction plate are waist-shaped holes, and their width dimensions are basically the same as the aperture of the third noise reduction hole 32a, while the length dimension can be reasonably designed according to the grading requirements of the perforation rate of the noise reduction device. The perforation rate of the noise reduction device in this embodiment ranges from 0.05% to 10%.

[0065] See also Figure 11 This embodiment also discloses a range hood, which includes a fan device 60, a smoke hood 70 in fluid communication with the fan device 60, and the above-mentioned noise reduction device 10. The fan device 60 includes a fan housing 61 and a centrifugal fan 62 disposed in the fan housing 61. The centrifugal fan 62 includes a volute 620 and an impeller 63 disposed in the volute 620. The impeller 63 is driven by a motor to rotate and generate a negative pressure for extracting and discharging oil smoke. The centrifugal fan 62 of this embodiment is horizontal, that is, the axis of the impeller 63 extends vertically. The air inlet 621 on the volute 620 is set downward. The side wall of the fan housing 61 has an air outlet 622 connected to the outlet of the volute 620. The air outlet 622 is provided with an air outlet hood 64, which can be used to connect to an external smoke exhaust pipe. The bottom of the fan housing 61 is open and connected to the first interface 41 of the noise reduction device 10. The second interface 42 of the first housing 40 can be connected to the top port of the smoke hood 70, or connected to the top port of the smoke hood 70 through a guide air duct 80. The first noise reduction plate 11 (the second noise reduction plate 21 and the auxiliary noise reduction plate 31) in the first housing 40 is inclined from bottom to top toward the location of the air inlet 621 of the centrifugal fan 62.

[0066] The above-mentioned first noise reduction plate 11, second noise reduction plate 21 and auxiliary noise reduction plate 31 are all arranged on the first box body 40 to form a modular structure that can be easily installed on the range hood body. During assembly, the corresponding noise reduction plate can be installed on the first box body 40 first, and then the entire module can be installed on the range hood body, which is more convenient and quick.

[0067] The range hood of this embodiment further includes a noise collection device (not shown) and a controller (not shown). The noise collection device may employ a microphone to collect noise information from the current operating state of the fan unit 60. The controller is electrically connected to the noise collection device and the drive mechanism of the noise reduction device, thereby controlling the operation of the drive mechanism based on the noise signal transmitted by the noise collection device, thereby moving the second noise reduction plate 21 and the auxiliary noise reduction plate 31 of the noise reduction device to positions that match the noise signal. Thus, during operation of the range hood, the noise reduction device can be adaptively adjusted based on the noise level of the range hood under its current operating conditions.

[0068] This embodiment also relates to a range hood control method, comprising the following steps:

[0069] S1, the range hood is started, and the fan device 60 operates at the default gear;

[0070] S2. The noise collecting device collects noise information of the current operating state of the fan device 60 and transmits the noise signal to the controller. The controller performs spectrum analysis to obtain the main noise frequency f;

[0071] S3. The controller controls the driving mechanism to move the second noise reduction plate 21 and the auxiliary noise reduction plate 31 to positions that match the main noise frequency f.

[0072] In the above step S3, "driving the second noise reduction plate 21 and the auxiliary noise reduction plate 31 to move to positions that match the main noise frequency f" can be pre-set according to the noise characteristics of the range hood, that is, the corresponding hole depth and perforation rate adjustment range can be designed accordingly. For example, with a noise range of 500Hz to 2000Hz (the actual adjustment range can be made larger, this is just an example), 500Hz can be used as a gear, and each gear has a corresponding hole depth (h1, h2, h3), perforation rate (δ1, δ2, δ3) and number of motor rotations. The specific corresponding method is as follows:

[0073]

[0074] The number of motor rotations means the number of rotations required for the noise reduction device to go from the initial state to the specified gear position (hole depth and perforation rate). Here, u, v, and w are all positive numbers, because the larger the hole depth, the smaller the perforation rate, and the lower the corresponding noise reduction frequency. Therefore, the number of motor rotations required to switch from the initial position to the corresponding gear position is: u>v>w.

[0075] Based on the above embodiments, other embodiments can be obtained by replacing and improving the relevant technical features. For example, the first box in the above-mentioned noise reduction device serves as a supporting component, and the first box can also be omitted, that is, the first noise reduction plate, the second noise reduction plate, the auxiliary noise reduction plate, the drive mechanism and other components can be directly installed into the housing (such as the fan frame) or the air guide duct of the range hood to achieve the same noise reduction effect. For another example, the third noise reduction holes of different sizes on the auxiliary noise reduction plate can also be arranged in a disordered manner on the auxiliary noise reduction plate, and are not limited to "the third noise reduction holes arranged in a row in the first straight line direction have the same size."

[0076] The "fluid communication" referred to in the present invention refers to the spatial position relationship between two components or parts (hereinafter collectively referred to as the first part and the second part), that is, the fluid (gas, liquid or a mixture of the two) can flow from the first part along the flow path or / and be transported to the second part. The first part and the second part can be directly connected, or the first part and the second part can be indirectly connected through at least one third party. The third party can be a fluid channel such as a pipe, channel, conduit, guide member, hole, groove, etc., or it can be a chamber allowing fluid to flow through, or a combination of the above.

Claims

1. A noise reduction device for a range hood, comprising: a first noise reduction plate (11) having first noise reduction holes (12) distributed thereon; It is characterized by also including: A second noise reduction plate (21) is arranged opposite to the first noise reduction plate (11) and can be moved closer to or farther away from the first noise reduction plate (11) by being driven by a driving mechanism. Second noise reduction holes (22) are provided on the second noise reduction plate (21) at positions corresponding to the first noise reduction holes (12). Each of the second noise reduction holes (22) on the second noise reduction plate (21) is connected to the corresponding first noise reduction hole (12) on the first noise reduction plate (11) via a conduit assembly with adjustable length. An auxiliary noise reduction plate (31) is slidably arranged on a side of the second noise reduction plate (21) away from the first noise reduction plate (11) along the plane where the second noise reduction plate (21) is located, and is provided with third noise reduction holes (32) that can be correspondingly connected to the second noise reduction holes (22) on the second noise reduction plate (21). The auxiliary noise reduction plate (31) can cover at least a portion of the second noise reduction holes (22) on the second noise reduction plate (21) during the sliding process relative to the second noise reduction plate (21); The auxiliary noise reduction plate (31) is arranged on the second noise reduction plate (21) in a manner capable of linear sliding relative to the second noise reduction plate (21), and the moving direction of the auxiliary noise reduction plate (31) relative to the second noise reduction plate (21) is recorded as a first linear direction; Each third noise reduction hole (32) on the auxiliary noise reduction plate (31) includes at least a first hole and a second hole, the size of the first hole in the first straight line direction is different from the size of the second hole in the first straight line direction, and when the auxiliary noise reduction plate (31) moves to different positions relative to the second noise reduction plate (21), different numbers of third noise reduction holes (32) on the auxiliary noise reduction plate (31) are correspondingly connected to the second noise reduction holes (22) of the second noise reduction plate (21).

2. The noise reduction device for a range hood according to claim 1, characterized in that: Each first noise reduction hole (12) on the first noise reduction plate (11) is provided with a first conduit (13) extending toward the second noise reduction plate (21); each corresponding second noise reduction hole (22) on the second noise reduction plate (21) is provided with a second conduit (23) extending toward the first noise reduction plate (11) and being sleeved together with the corresponding first conduit (13); the first conduit (13) and the second conduit (23) together constitute the conduit assembly.

3. The noise reduction device for a range hood according to claim 2, characterized in that: The second conduit (23) is sleeved outside the first conduit (13), and the inner peripheral wall of the second conduit (23) is in sealing contact with the outer peripheral wall of the first conduit (13).

4. The noise reduction device for a range hood according to claim 1, characterized in that: The driving mechanism comprises a driving motor (51) and a screw-slider transmission assembly, and the output shaft of the driving motor (51) is transmission-connected to the second noise reduction plate (21) via the screw-slider transmission assembly.

5. The noise reduction device for a range hood according to claim 1, characterized in that: A row of second noise reduction holes (22) arranged along the first straight line on the second noise reduction plate (21) is recorded as a second noise reduction hole group, and the second noise reduction holes (22) in each second noise reduction hole group have the same size; A row of third noise reduction holes (32) arranged along the first straight line direction on the auxiliary noise reduction plate (31) is recorded as a third noise reduction hole group, and the third noise reduction holes (32) in each third noise reduction hole group have the same size. At least two third noise reduction hole groups on the auxiliary noise reduction plate (31) have different sizes. When the auxiliary noise reduction plate (31) moves to different positions relative to the second noise reduction plate (21), different numbers of third noise reduction hole groups on the auxiliary noise reduction plate (31) are correspondingly connected to the second noise reduction hole group of the second noise reduction plate (21).

6. The noise reduction device for a range hood according to claim 5, characterized in that: The second noise reduction plate (21) is provided with a slide groove (24) extending along the first straight line direction, and the auxiliary noise reduction plate (31) is slidably constrained in the slide groove (24).

7. The noise reduction device for a range hood according to claim 1, characterized in that: The invention also includes a first box (40), wherein a channel for sound propagation is defined in the first box (40), the first noise reduction plate (11), the second noise reduction plate (21) and the auxiliary noise reduction plate (31) are all arranged in the channel of the first box (40), the first noise reduction plate (11) is fixed relative to the first box (40), and a swing rod (44) is further provided between the auxiliary noise reduction plate (31) and the first box (40), the first end of the swing rod (44) is rotationally connected to the auxiliary noise reduction plate (31), and the second end is rotationally connected to the first box (40), and when the second noise reduction plate (21) moves relative to the first noise reduction plate (11), force is transmitted to the auxiliary noise reduction plate (31) through the swing rod (44), thereby driving the auxiliary noise reduction plate (31) to move relative to the second noise reduction plate (21).

8. The noise reduction device for a range hood according to claim 7, characterized in that: The second noise reduction plate (21) has at least a first vertical position and a second vertical position during movement relative to the first noise reduction plate (11); when the second noise reduction plate (21) is in the first vertical position, the distance between the second noise reduction plate (21) and the first noise reduction plate (11) is recorded as a first distance; when the second noise reduction plate (21) is in the second vertical position, the distance between the second noise reduction plate (21) and the first noise reduction plate (11) is recorded as a second distance; the first distance is smaller than the second distance; The auxiliary noise reduction plate (31) has at least a first horizontal position corresponding to the first vertical position of the second noise reduction plate (21) and a second horizontal position corresponding to the second vertical position of the second noise reduction plate during movement relative to the second noise reduction plate (21); when the auxiliary noise reduction plate (31) is in the first horizontal position, the number of corresponding connections between the third noise reduction holes (32) on the auxiliary noise reduction plate (31) and the second noise reduction holes (22) on the second noise reduction plate (21) is greater than the number of corresponding connections between the third noise reduction holes (32) on the auxiliary noise reduction plate (31) and the second noise reduction holes (22) on the second noise reduction plate (21) when the auxiliary noise reduction plate (31) is in the second horizontal position.

9. A range hood comprising a fan device (60) and a fume collecting hood in fluid communication with the fan device (60), characterized in that It also includes a noise reduction device for a range hood according to any one of claims 1 to 6, wherein the noise reduction device is provided on a flow path between the fan device (60) and the fume hood and is arranged adjacent to the fan device (60).

10. A range hood comprising a fan device (60) and a fume collecting hood in fluid communication with the fan device (60), characterized in that It also includes a noise reduction device for a range hood according to claim 7 or 8, the noise reduction device is arranged on the flow path between the fan device (60) and the smoke hood, and is arranged adjacent to the fan device (60), the fan device (60) includes a fan housing (61) and a centrifugal fan (62) arranged in the fan housing (61), the centrifugal fan (62) has a downward air inlet (621), the first housing (40) of the noise reduction device is connected to the bottom of the fan housing (61), the first noise reduction plate (11) is arranged on the inner wall of the first housing (40), and is inclined from bottom to top toward the position of the air inlet (621) of the centrifugal fan (62).

11. The range hood according to claim 10, characterized in that Also includes: A noise collecting device for collecting noise information under the current operating state of the fan device (60); The controller is electrically connected to the driving mechanisms of the noise collecting device and the noise reducing device, thereby controlling the operation of the driving mechanisms according to the noise signal transmitted by the noise collecting device, and moving the second noise reducing plate (21) and the auxiliary noise reducing plate (31) of the noise reducing device to positions matching the noise signal.

12. A control method for a range hood according to claim 11, characterized in that The following steps are involved: S1, the range hood is started, and the fan device (60) operates at a default gear; S2, the noise collecting device collects noise information in the current operating state of the fan device (60), and transmits the noise signal to the controller, which performs spectrum analysis to obtain the main noise frequency f; S3, the controller controls the driving mechanism to move, driving the second noise reduction plate (21) and the auxiliary noise reduction plate (31) to move to positions matching the main noise frequency f.

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