A range hood and a control method thereof

Abstract

The application relates to an oil fume extractor and a control method thereof, wherein the oil fume extractor comprises a fan frame and a fan system arranged in the fan frame, the fan system comprises a volute, an impeller rotatably arranged in the volute, and a motor mounted on the volute and connected with the impeller driving end for driving the impeller to rotate, characterized in that the oil fume extractor further comprises a piezoelectric module arranged between the motor and the volute and made of piezoelectric material capable of being deformed after being electrified, a vibration identification module arranged in the volute and used for identifying the vibration signal of the volute, and a controller connected with the vibration identification module and the piezoelectric module and configured to control the piezoelectric module to be deformed correspondingly according to the identification result of the vibration identification module so as to weaken the vibration of the volute. Therefore, the impeller and the volute always work in a state with low vibration, the operation is more stable, the vibration noise is reduced, and the use experience is improved.

Description

Technical Field

[0001] This invention relates to the field of kitchen appliance technology, and in particular to a range hood and its control method. Background Technology

[0002] A range hood is a kitchen appliance designed to purify the kitchen environment. It works on the principle of fluid dynamics, using a centrifugal fan installed inside to draw in and exhaust cooking fumes. The centrifugal fan consists of a casing, an impeller housed within the casing, and a motor that drives the impeller. As the impeller rotates, a negative pressure is generated at the center of the fan, drawing in the cooking fumes from below. After being accelerated by the fan, the fumes are collected by the casing and guided outwards.

[0003] Currently, most range hoods on the market mount the impeller onto the motor's output shaft. When the motor housing is fixed to the motor mounting bracket of the volute, rubber pads (also known as "vibration damping pads") are used to reduce impeller vibration and thus reduce vibration noise. For example, Chinese utility model patent number ZL202223169026.8 (authorization announcement number CN218862902U) discloses a fan and range hood, in which part of the vibration damping column is located between the motor mounting bracket and the mounting foot, and part is located between the mounting foot and the head of the motor limit screw. This provides vibration damping on both sides of the mounting foot, reducing vibration noise between the mounting foot and the motor mounting bracket, as well as vibration noise between the mounting foot and the head of the motor limit screw.

[0004] However, because rubber pads are highly susceptible to deformation and their properties change inconsistently with motor operating temperature, the axial vibration of the impeller can easily exceed limits, leading to a reduction in the performance of the fan system. Current technology only addresses this issue by using rubber pads with better vibration damping. While this is effective for vibrations under normal conditions, it fails to address situations where temperature increases cause inconsistent changes in rubber pad properties or where vibration frequencies fall outside the pad's damping range during operation. These solutions do not fundamentally solve the problem, and once this issue arises, it can easily cause excessive vibration in the volute and impeller, leading to unstable airflow within the volute, increased airflow noise and vibration, reduced fan system performance, and a significant impact on the user's cooking experience. Therefore, further improvements to the existing technology are necessary. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a range hood that can make the impeller and volute always work in a low-vibration state, so as to make the impeller run more smoothly and reduce aerodynamic noise.

[0006] The second technical problem to be solved by the present invention is to provide a control method for the above-mentioned range hood.

[0007] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a range hood, including a fan frame and a fan system disposed within the fan frame, wherein the fan system includes:

[0008] Snail shell;

[0009] The impeller is rotatably housed within the volute.

[0010] The motor is mounted on the volute and its power output end is connected to the impeller drive to drive the impeller to rotate.

[0011] The characteristic feature is that the range hood also includes:

[0012] The piezoelectric module is located between the motor and the volute and is made of a piezoelectric material that can deform when energized.

[0013] The vibration recognition module, located inside the volute, is used to identify the vibration signals of the volute.

[0014] The controller, connected to the vibration recognition module and the piezoelectric module, is configured to control the piezoelectric module to undergo corresponding deformation based on the recognition result of the vibration recognition module, so as to reduce the vibration of the volute.

[0015] To achieve the fixation between the motor and the volute, the volute includes a front cover plate and a rear cover plate arranged at intervals. The front cover plate has an air inlet, and the rear cover plate has an installation port through which the motor passes. The outer peripheral wall of the motor is provided with a skirt. The skirt and the rear cover plate are arranged side by side and at least partially overlap. The skirt and the rear cover plate are connected to fix the motor and the volute.

[0016] To achieve a vibration reduction effect, mounting holes are provided on the skirt, and vibration damping pads are provided at the mounting holes. The ends of the vibration damping pads extend out of the mounting holes, and the piezoelectric module is located between the ends of the vibration damping pads and the rear cover plate.

[0017] Preferably, there are multiple piezoelectric modules, and each piezoelectric module is arranged at uniform intervals along the outer circumference of the motor.

[0018] Preferably, the vibration recognition module is a vibration sensor installed on the rear cover plate.

[0019] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a control method for a range hood as described above, characterized by comprising the following steps:

[0020] Step 1: Turn on the range hood;

[0021] Step 2: Determine whether the current fan is in the speed-up or speed-down phase. If yes, proceed to step 14; otherwise, proceed to step 3.

[0022] Step 3: Determine whether the current operation of the wind turbine has reached a stable state. If yes, proceed to Step 4; otherwise, end the process.

[0023] Step 4: Acquire the piezoelectric module electrical signal for a certain duration, perform frequency domain analysis on the electrical signal, sort the amplitude values ​​obtained from the frequency domain analysis in descending order, extract the i-th ranked amplitude value and the frequency and time corresponding to that amplitude value, with the initial value of i being 1;

[0024] Step 5: Determine if the current value of i is less than or equal to the preset value h0. If yes, proceed to step 6; otherwise, end.

[0025] Step 6: Based on the value of j, construct the first relationship between the amplitude of the j-th order and time and the second relationship between the frequency and time, and then proceed to step 7. The initial value of j is 1.

[0026] Step 7: Based on the first and second relations, construct the third relation of the change of the electrical signal of the piezoelectric module with time;

[0027] Step 8: Select the amplitude of one of the piezoelectric modules as the reference point for the third relational expression;

[0028] Step 9: Adjust the values ​​of each piezoelectric module in real time according to the third relational formula to reduce vibration;

[0029] Step 10: Determine whether the amplitude of the i-th time decreases by the set reduction threshold p1%. If yes, proceed to step 11; otherwise, proceed to step 12.

[0030] Step 11: Increment the current value of i by 1, and proceed to step 5;

[0031] Step 12: Determine whether the current value of j is greater than the preset value J. If yes, proceed to step 11; otherwise, proceed to step 13.

[0032] Step 13: Increment the current j by 1 and proceed to step 6;

[0033] Step 14: During the fan speed-up or speed-down phase, adjust each piezoelectric module according to the preset electrical signal curve of each piezoelectric module.

[0034] To determine the operating stage of the wind turbine, the specific steps in step 2 to determine whether the wind turbine is currently in the acceleration or deceleration stage are as follows:

[0035] Step 2-1: Monitor the time it takes for the maximum amplitude to reach each piezoelectric module;

[0036] Step 2-2: Calculate the acceleration t based on the time it takes for the maximum amplitude to reach each piezoelectric module;

[0037] Steps 2-3: Determine whether the acceleration t is greater than the preset threshold m0. If yes, determine whether the current fan is in the acceleration or deceleration stage; otherwise, the current fan is not in the acceleration or deceleration stage.

[0038] Specifically, there are four piezoelectric modules, distributed sequentially according to the rotational order of the impellers. Therefore, the formula for calculating the acceleration t in step 2-2 is:

[0039] t=(1 / (t4-t2)-1 / (t3-t1)) / (t3-t2)

[0040] Where t1, t2, t3, and t4 represent the times when the maximum amplitude arrives at each piezoelectric module in sequence.

[0041] To determine whether the wind turbine has reached a stable operating state, step 3 involves the following steps:

[0042] Step 3-1: Extract the piezoelectric module electrical signal for a certain duration, perform a fast Fourier transform on it, and extract the frequency change extreme value corresponding to the maximum amplitude of the fast Fourier transform.

[0043] Step 3-2: Determine whether the frequency fluctuation is less than n0 and n0 is not equal to 0 based on the extreme value of frequency change. If yes, it is determined that the current wind turbine has reached a stable state; otherwise, it is determined that the current wind turbine has not reached a stable state.

[0044] Preferably, the expression for the third relation in step 7 is:

[0045] E=k1*f1(t)*sin(2*pi*f2(t)*t)

[0046] Where E is the electrical signal of the piezoelectric module, k1 is the coefficient of the vibration damping pad, and k1 varies with the temperature of the vibration damping pad; f1(t) is the first relationship of the j-th order amplitude changing with time, and f2(t) is the second relationship of the frequency changing with time.

[0047] In the above scheme, the specific steps of step 14 are as follows:

[0048] Step 14-1: Select the amplitude of one of the piezoelectric modules as the reference point for the third relational expression;

[0049] Step 14-2: Adjust each piezoelectric module according to the preset electrical signal change curve of each piezoelectric module;

[0050] Step 14-3: Record and update the adjustment duration t0;

[0051] Step 14-4: Determine whether the current operation of the wind turbine has reached a stable state. If yes, proceed to step 14-5; otherwise, end.

[0052] Step 14-5: Update the preset electrical signal change curves of each piezoelectric module using time t0, and then proceed to step 3.

[0053] Compared with the prior art, the advantages of the present invention are as follows: by identifying the vibration signal of the volute through the vibration identification module, the controller can control the piezoelectric module to undergo corresponding deformation according to the identification result of the vibration identification module, so as to reduce the vibration of the volute, thereby making the impeller and volute always work in a low vibration state, which makes the operation more stable, reduces vibration noise, and can not only ensure the performance of the fan when the user uses it, but also ensure the normal operation of the whole machine, thus improving the user experience. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the range hood in an embodiment of the present invention;

[0055] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0056] Figure 3 for Figure 1 A schematic diagram of the structure of the fan system in the diagram;

[0057] Figure 4 for Figure 3 A sectional view;

[0058] Figure 5 for Figure 3 Schematic diagram of the assembly structure of the impeller and motor;

[0059] Figure 6 This is a schematic diagram of the motor assembly structure in an embodiment of the present invention;

[0060] Figure 7 for Figure 6 Partially exploded diagram. Detailed Implementation

[0061] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0062] like Figures 1-7As shown, the range hood in this embodiment includes a fan frame a, a fan system b disposed within the fan frame a, a piezoelectric module 4, a vibration recognition module, and a controller. The fan system b includes a volute 1, an impeller 2 rotatably disposed within the volute 1, and a motor 3 for driving the impeller 2. The motor 3 is mounted on the volute 1, and its power output end is connected to the impeller 2. The piezoelectric module 4 is disposed between the motor 3 and the volute 1, and is made of a piezoelectric material that deforms when energized. This piezoelectric module 4 utilizes the energized expansion and contraction effect of the piezoelectric material to reduce the vibration of the volute. The vibration recognition module is disposed within the volute 1 and is used to identify the vibration signal of the volute. The controller is connected to the vibration recognition module and the piezoelectric module 4 and is configured to: control the piezoelectric module 4 to undergo corresponding deformation based on the identification result of the vibration recognition module, thereby reducing the vibration of the volute 1.

[0063] The volute 1 includes a front cover plate 11 and a rear cover plate 12 arranged at intervals, and an annular wall 13 connecting the front cover plate 11 and the rear cover plate 12. The front cover plate 11 has an air inlet 111, and the rear cover plate 12 has an installation port 121 through which the motor 3 passes. The outer peripheral wall of the motor 3 has a skirt 31, which is arranged side-by-side with the rear cover plate 12 and at least partially overlaps it. The skirt 31 is connected to the rear cover plate 12 to fix the motor 3 to the volute 1. Figure 6 As shown, the skirt 31 is ring-shaped, and of course, the skirt 31 consists of multiple mounting parts spaced apart.

[0064] Mounting holes 311 are provided on the skirt 31 (the number of mounting holes 311 is the same as the number of piezoelectric modules 4). Vibration damping pads 7 are installed at the mounting holes 311, with the ends of the damping pads 7 extending beyond the mounting holes 311. The piezoelectric modules 4 are positioned between the ends of the damping pads 7 and the rear cover plate 12. Furthermore, the number of damping pads 7 is the same as the number of piezoelectric modules 4, ensuring that each damping pad 7 is followed by a piezoelectric module. Bolts 8 pass through the damping pads 7 and piezoelectric modules 4 in sequence, thereby securing the motor 3 to the volute 1.

[0065] In this embodiment, the vibration identification module is a vibration sensor installed on the rear cover plate 12, which can determine the current vibration state of the impeller.

[0066] There are multiple piezoelectric modules 4, and each piezoelectric module 4 is arranged at even intervals along the outer circumference of the motor 3. For example... Figure 3 and 5 As shown, there are four piezoelectric modules 4 in this embodiment, and they are distributed in sequence according to the rotation order of the impeller.

[0067] The control method for the above-mentioned range hood includes the following steps:

[0068] Step 1: Turn on the range hood;

[0069] Step 2: Determine whether the current fan is in the speed-up or speed-down phase. If yes, proceed to step 14; otherwise, proceed to step 3.

[0070] The specific steps to determine whether the current fan is in the acceleration or deceleration phase are as follows:

[0071] Step 2-1: Monitor the time it takes for the maximum amplitude to reach each piezoelectric module;

[0072] Step 2-2: Calculate the acceleration t based on the time it takes for the maximum amplitude to reach each piezoelectric module;

[0073] In this embodiment, the formula for calculating acceleration t is:

[0074] t=(1 / (t4-t2)-1 / (t3-t1)) / (t3-t2)

[0075] Where t1, t2, t3, and t4 are the times when the maximum amplitude arrives at each piezoelectric module in sequence.

[0076] Steps 2-3: Determine whether the acceleration t is greater than the preset threshold m0. If yes, determine whether the current fan is in the acceleration or deceleration phase; otherwise, the current fan is not in the acceleration or deceleration phase.

[0077] Step 3: Determine whether the current operation of the wind turbine has reached a stable state. If yes, proceed to Step 4; otherwise, end the process.

[0078] The specific steps to determine whether the current wind turbine operation has reached a stable state are as follows:

[0079] Step 3-1: Extract the piezoelectric module electrical signal for a certain duration, perform a fast Fourier transform on it, and extract the frequency change extreme value corresponding to the maximum amplitude of the fast Fourier transform.

[0080] Step 3-2: Determine whether the frequency fluctuation is less than n0 and n0 is not equal to 0 based on the extreme value of frequency change. If n0 is the preset frequency fluctuation value, it is determined that the current wind turbine has reached a stable state; otherwise, it is determined that the current wind turbine has not reached a stable state.

[0081] Step 4: Acquire the piezoelectric module electrical signal for a certain duration, perform frequency domain analysis on the electrical signal, and sort the amplitude values ​​obtained from the frequency domain analysis in descending order. Extract the amplitude value ranked i and the frequency and time corresponding to that amplitude value; the initial value of i is 1.

[0082] Step 5: Determine if the current value of i is less than or equal to the preset value h0. If yes, proceed to step 6; otherwise, end.

[0083] Step 6: Based on the value of j, construct the first relationship between the amplitude of the j-th order and time and the second relationship between the frequency and time, and then proceed to step 7; the initial value of j is 1.

[0084] Step 7: Based on the first and second relations, construct the third relation of the change of the electrical signal of the piezoelectric module with time;

[0085] The expression for the third relation is:

[0086] E=k1*f1(t)*sin(2*pi*f2(t)*t)

[0087] Where E is the electrical signal of the piezoelectric module, k1 is the coefficient of the vibration damping pad, and k1 varies with the temperature of the vibration damping pad; f1(t) is the first relationship between the j-th order amplitude and time, and f2(t) is the second relationship between the frequency and time.

[0088] The third relationship mentioned above can adjust the impeller stability based on the temperature of the damping pad, greatly improving the applicable operating conditions of the fan;

[0089] Step 8: Select the amplitude of one of the piezoelectric modules as the reference point for the third relational expression;

[0090] Step 9: Adjust the values ​​of each piezoelectric module in real time according to the third relational formula to reduce vibration;

[0091] Step 10: Determine whether the amplitude of the i-th time decreases by the set reduction threshold p1%. If yes, proceed to step 11; otherwise, proceed to step 12.

[0092] Step 11: Increment the current value of i by 1, and proceed to step 5;

[0093] Step 12: Determine whether the current value of j is greater than the preset value J. If yes, proceed to step 11; otherwise, proceed to step 13.

[0094] Step 13: Increment the current j by 1 and proceed to step 6;

[0095] Step 14: During the fan speed-up or speed-down phase, adjust each piezoelectric module according to the preset electrical signal curve of each piezoelectric module.

[0096] Specifically, the steps in step 14 are as follows:

[0097] Step 14-1: Select the amplitude of one of the piezoelectric modules as the reference point for the third relational expression;

[0098] Step 14-2: Adjust each piezoelectric module according to the preset electrical signal change curve of each piezoelectric module;

[0099] Step 14-3: Record and update the adjustment duration t0;

[0100] Step 14-4: Determine whether the current operation of the wind turbine has reached a stable state. If yes, proceed to step 14-5; otherwise, end.

[0101] Step 14-5: Update the preset electrical signal change curves of each piezoelectric module using time t0, and then proceed to step 3.

[0102] The above control method mainly utilizes the principle that: by causing corresponding deformation of each piezoelectric module, the piezoelectric module is controlled to undergo corresponding deformation, thereby reducing the vibration of the volute. This enables real-time adjustment of impeller stability, reduces vibration during operation, reduces aerodynamic noise, and significantly reduces the vibration of the impeller relative to the volute during operation, greatly improving the impeller's operational stability and maximizing the performance of the fan.

Claims

1. A control method of a range hood, the range hood comprising a fan frame (a) and a fan system (b) arranged in the fan frame (a), the fan system (b) comprising: a volute (1); an impeller (2) rotatably arranged in the volute (1); and a motor (3) mounted on the volute (1) and having a power output end drivingly connected to the impeller (2) for driving the impeller (2) to rotate, characterized in that the range hood further comprises: a piezoelectric module (4) arranged between the motor (3) and the volute (1) and made of piezoelectric material capable of deforming after being electrified; a vibration identification module arranged in the volute (1) and configured to identify a vibration signal of the volute (1); and a controller connected to the vibration identification module and the piezoelectric module (4) and configured to control the piezoelectric module (4) to deform correspondingly according to an identification result of the vibration identification module so as to weaken the vibration of the volute (1); and the control method of the range hood comprises the following steps: Step 1: turning on the range hood; Step 2: determining whether the current fan is in a speed-up or speed-down stage, and if yes, proceeding to Step 14; otherwise, proceeding to Step 3; Step 3: determining whether the current fan operation reaches a stable state, and if yes, proceeding to Step 4; otherwise, ending; Step 4: collecting piezoelectric module electric signals for a certain time length, performing frequency domain analysis on the electric signals, sorting amplitudes obtained by the frequency domain analysis from large to small, and extracting an amplitude ranked at i-th, a frequency corresponding to the amplitude, and a time, wherein i is initially 1; Step 5: determining whether the current i value is less than or equal to a preset value h0, and if yes, proceeding to Step 6; otherwise, ending; Step 6: constructing a first relationship formula of j-th amplitude changing with time and a second relationship formula of frequency changing with time according to a j value, and proceeding to Step 7, wherein j is initially 1; Step 7: constructing a third relationship formula of piezoelectric module electric signals changing with time according to the first relationship formula and the second relationship formula; Step 8: selecting an amplitude of one of the piezoelectric modules as a reference point of the third relationship formula; Step 9: adjusting values of the piezoelectric modules in real time according to the third relationship formula so as to weaken the vibration; Step 10: determining whether the i-th amplitude is reduced by a set reduction threshold p1%, and if yes, proceeding to Step 11; otherwise, proceeding to Step 12; Step 11: increasing the current i value by 1 and proceeding to Step 5; Step 12: determining whether the current j value is greater than a preset value J, and if yes, proceeding to Step 11; otherwise, proceeding to Step 13; Step 13: increasing the current j by 1 and proceeding to Step 6; and Step 14: adjusting the piezoelectric modules according to preset piezoelectric module electric signal curves during the speed-up or speed-down stage of the fan. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. The control method according to claim 1, characterized by: The volute (1) comprises front cover plate (11) and rear cover plate (12) arranged in front and back, the front cover plate (11) is provided with air inlet (111), the rear cover plate (12) is provided with installation opening (121) for motor (3) to pass through, the outer wall of the motor (3) is provided with skirt (31), the skirt (31) is arranged side by side with the rear cover plate (12) in front and back and at least partially overlaps, the skirt (31) is connected with the rear cover plate (12) so that the motor (3) is fixed with the volute (1).

3. The control method according to claim 2, characterized in that: The skirt (31) is provided with mounting hole (311), the mounting hole (311) is provided with damping pad (7), the end of the damping pad (7) is out of the mounting hole (311), and the piezoelectric module is arranged between the end of the damping pad (7) and the rear cover plate (12).

4. The control method according to claim 3, characterized in that: The piezoelectric module is multiple, each piezoelectric module is arranged along the outer periphery of the motor (3) in uniform interval.

5. The control method according to any one of claims 1 to 4, characterized in that: The vibration identification module is a vibration sensor arranged on the rear cover plate (12).

6. The control method according to claim 1, characterized by: The specific steps of judging whether the current fan is in the acceleration or deceleration stage in step 2 are as follows: Step 2-1, monitoring the time when the maximum amplitude reaches each piezoelectric module; Step 2-2, calculating the acceleration t according to the time when the maximum amplitude reaches each piezoelectric module; Step 2-3, judging whether the acceleration t is greater than the preset threshold m0, if yes, it is determined that the current fan is in the acceleration or deceleration stage; if not, the current fan is not in the acceleration or deceleration stage.

7. The control method according to claim 6, characterized in that: The piezoelectric module is four, and is distributed in sequence according to the rotation order of the impeller, and the calculation formula of the acceleration t in step 2-2 is as follows: t=(1 / (t4-t2)-1 / (t3-t1)) / (t3-t2) Wherein, t1, t2, t3, t4 are the times when the maximum amplitude reaches each piezoelectric module in sequence.

8. The control method according to claim 3 or 4, characterized by: The specific steps of judging whether the current fan reaches the stable state in step 3 are as follows: Step 3-1, extracting the piezoelectric module electric signal for a certain time, performing fast Fourier transform on it, and extracting the frequency change extreme value corresponding to the maximum amplitude of the fast Fourier transform; Step 3-2, judging whether the frequency fluctuation is less than n0 and n0 is not equal to 0 according to the frequency change extreme value, n0 is the preset frequency fluctuation value, if yes, it is determined that the current fan reaches the stable state; If not, it is determined that the current fan does not reach the stable state.

9. The control method according to claim 8, characterized in that: The expression of the third relationship in step 7 is as follows: E=k1*f1(t)*sin(2*pi*f2(t)*t) Wherein, E is the electric signal of the piezoelectric module, k1 is the coefficient of the damping pad, which changes with the temperature of the damping pad; f1(t) is the first relationship of the j order amplitude changing with time, and f2(t) is the second relationship of the frequency changing with time.

10. The control method according to claim 9, characterized in that: The specific steps of step 14 are as follows: Step 14-1, selecting the amplitude of one of the piezoelectric modules as the reference point of the third relationship; Step 14-2, adjusting each piezoelectric module according to the preset electric signal change curve of each piezoelectric module; Step 14-3, recording and updating the adjustment time t0; Step 14-4, judging whether the current fan operation reaches a stable state, if yes, then turning to step 14-5; if no, then ending; Step 14-5, updating the preset electric signal change curve of each piezoelectric module by using time t0, and turning to step 3.

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