Range hood and vibration reduction control method thereof

Abstract

The invention relates to an extractor hood and a vibration reduction control method of the extractor hood, and the extractor hood comprises a dynamic balance adjusting device which comprises a mounting bracket fixed relative to a volute and a rotating arm which is driven by a first driving device to be rotatably arranged on the mounting bracket, a limiting sliding way extending in the length direction of the rotating arm is further defined on the rotating arm, a balancing weight limited in the limiting sliding way in a sliding mode is further arranged on the rotating arm, and a telescopic spring is further arranged in the limiting sliding way and acts on the balancing weight. The first end of the rotating arm is further provided with a winch used for winding a pull rope and a pull rope motor used for driving the winch to rotate, the end, wound on the winch, of the pull rope is connected with the balancing weight, and the balancing weight can be driven by the pull rope motor to overcome the elastic force of the telescopic spring to be close to the first axis. The device has the advantages that the dynamic balance of the impeller is adaptively adjusted according to the specific use condition of the range hood, and then the vibration condition of the range hood is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of kitchen appliances, and in particular to a range hood and a vibration reduction control method for the range hood. Background Art

[0002] A range hood is a kitchen appliance that purifies the kitchen environment. It operates based on the principles of fluid dynamics. A centrifugal fan installed inside the range hood draws in and exhausts cooking fumes, while a filter removes some grease particles. A centrifugal fan consists of a volute, an impeller mounted within the volute, and a motor that drives the impeller. As the impeller rotates, negative pressure is generated at the fan's center, drawing cooking fumes from beneath the range hood into the fan. After being accelerated by the fan, the volute collects them and guides them out of the room.

[0003] The vibration of the range hood is mainly due to the vibration of the motor itself and the imbalance of the impeller's dynamic balance, which drives the imbalance of the dynamic balance of the entire fan system and causes vibration. These vibrations will be transmitted to the entire range hood through the installation and fixing structure, thereby causing the entire machine to vibrate, which brings a bad user experience. The general solution is to reduce the resonance by adjusting the motor parameters to reduce the vibration of the motor itself, adjusting the dynamic balance of the impeller, changing the mode of the entire machine structure, etc. For example, the Chinese invention patent application with application number CN202010479376.0 (publication number CN111536568A) discloses a range hood, which effectively reduces the resonance and abnormal noise of the entire machine by arranging a double triangular support structure at the connection between the top plate and the side plate, arranging a first vibration reduction structure on the top plate, and arranging a second vibration reduction structure on the side plate. The whole machine has good structural strength and low noise. Among them, the first vibration reduction structure is selected as a bidirectional shock-absorbing arc structure, with the "double triangle" support structure as the end point, and the "horn-type" structure is unfolded, so that the top plate mode becomes 116 Hz, avoiding the excitation of nearly 100 Hz, and reducing the structural noise of the whole machine; the annular second vibration reduction structure makes the side panel mode become 141 Hz, avoiding the excitation of nearly 100 Hz, and reducing the structural noise of the whole machine; the double triangle support structure, the first vibration reduction structure and the second vibration reduction structure can be combined in pairs to make the natural frequency of the whole system high, the rigidity of the whole machine enhanced, ensure structural stability, and avoid the generation of resonance and abnormal noise.

[0004] However, the existing solution to the vibration of range hoods still has certain shortcomings: the same solution is used for all range hood products, and it is a one-time solution. That is, after the whole machine is assembled, its vibration can no longer be changed, not to mention that after a period of use in the user's home, the modal changes caused by grease or external environmental influences will aggravate the vibration of the whole machine and reduce the user experience. In addition, during the vibration and noise testing process, the applicant found that different machines with the same design had different vibration conditions. The reason is that the gap deviation and structural deviation during the assembly process lead to different impeller, volute, and motor modes of the same design. Therefore, if the mode is improved only by modifying the structural design, it can only reduce the vibration of some machines, and cannot solve the imbalance and vibration caused by processing errors / assembly errors.

[0005] Therefore, existing range hoods also need further improvement. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a range hood that can adaptively adjust the dynamic balance of the impeller according to the specific operating conditions of the range hood, thereby effectively improving the vibration of the range hood, in response to the current status of the existing technology.

[0007] The second technical problem to be solved by the present invention is to provide a vibration reduction control method that can adaptively adjust the dynamic balance of the impeller according to the specific operating conditions of the range hood, thereby effectively improving the vibration of the range hood, based on the current status of the existing technology.

[0008] The technical solution adopted by the present invention to solve the first technical problem is: a range hood comprising:

[0009] A centrifugal fan comprises a volute, an impeller rotating in the volute, and a main motor for driving the impeller to rotate;

[0010] Also includes:

[0011] The dynamic balancing adjustment device includes a mounting bracket fixed relative to the volute and a rotating arm driven by a first drive device to rotate on the mounting bracket. The rotating axis of the rotating arm relative to the mounting bracket is recorded as a first axis. The first axis is collinear with the axis of the main motor. The rotation direction of the rotating arm is opposite to the rotation direction of the impeller. The rotating arm has a first end adjacent to the first axis and a second end away from the first axis. The rotating arm also defines a limiting slide extending along its length and a counterweight block slidingly constrained in the limiting slide. The limiting slide is also provided with a telescopic spring, which acts on the counterweight block and causes the counterweight block to always have a tendency to move toward the second end of the rotating arm. The first end of the rotating arm is also provided with a winch for winding a pull rope and a pull rope motor for driving the winch to rotate. The end of the pull rope wound on the winch extends into the limiting slide and is connected to the counterweight block, and can be driven by the pull rope motor to make the counterweight block overcome the elastic force of the telescopic spring and approach the first axis.

[0012] In order to limit and fix one end of the telescopic spring, thereby ensuring the stability of the counterweight block moving along the limiting slide, the rotating arm also has a limiting stop portion extending toward the inside of the limiting slide at a position adjacent to its first end, and one end of the telescopic spring toward the first end of the rotating arm rests on the limiting stop portion.

[0013] In order to facilitate better application of force to the counterweight by the pull rope and avoid knotting problems caused by stretching, the pull rope passes through the telescopic spring and is connected to the counterweight.

[0014] In order to achieve dynamic adjustment of the vibration reduction of the range hood, it also includes a vibration state detection device for detecting the vibration state of the main motor or the impeller. The vibration state detection device and the pull-rope motor are electrically connected to the control system of the range hood. The control system of the range hood can control the action of the pull-rope motor according to the vibration state signal transmitted by the vibration state detection device, thereby driving the counterweight block to move to an appropriate position.

[0015] As an improvement, the vibration state detection device includes an acceleration sensor provided on the main motor body. It is conceivable that the vibration state detection device is not limited to monitoring the vibration acceleration of the main motor, but can also monitor other vibration-related parameters such as impeller vibration acceleration or dynamic balance as a judgment condition to adjust the dynamic balance adjustment device.

[0016] In order to drive the rotating arm to rotate, the first driving device includes a first driving motor, the main body of the first driving motor is arranged on the mounting bracket, and the axis of the first driving motor is collinear with the axis of the main motor. The end of the rotating arm is connected to the output shaft of the first driving motor, so that it can rotate under the drive of the first driving motor.

[0017] The vibration reduction adjustment of the range hood can be achieved by adjusting the position of the counterweight on the rotating arm, or by adjusting the rotational speed of the rotating arm. In order to provide a compensation means for dynamic balance adjustment on the basis of "adjusting the position of the counterweight on the rotating arm to achieve dynamic balance adjustment", it also includes a vibration state detection device for detecting the vibration state of the main motor or impeller. The vibration state detection device and the first drive motor are electrically connected to the control system of the range hood. The control system of the range hood can control the rotational speed of the first drive motor according to the vibration state signal transmitted by the vibration state detection device.

[0018] The technical solution adopted by the present invention to solve the second technical problem is: a vibration reduction control method for a range hood, comprising the following steps: after the main motor of the range hood is driven, a vibration state detection device detects the vibration state of the main motor or impeller and obtains the vibration state signal of the main motor or impeller; when the vibration detection state detection value reaches or exceeds the set threshold, the dynamic balance adjustment device is started to adjust the position of the counterweight on the rotating arm and the speed range of the rotating arm in turn until the vibration detection state detection value of the main motor or impeller is less than the set threshold.

[0019] As an improvement, the vibration reduction control method of the range hood includes the following steps:

[0020] S1. The centrifugal fan starts and the speed of the main motor stabilizes within the set speed range within the set time [S n-1 ,S n ], the main motor is in different speed ranges [S n-1 ,S n ], the vibration state setting threshold value an of the main motor or impeller is also different, wherein the vibration state setting threshold value a of the main motor or impeller is n The speed range of the main motor [S n-1 ,S n ] one-to-one correspondence;

[0021] S2, the vibration state detection device detects the vibration state of the main motor or impeller, and obtains the vibration state signal of the main motor or impeller under the current working condition, and determines whether the current vibration detection state detection value A0 reaches or exceeds the set threshold value a nIf so, the dynamic balancing adjustment device is started, and the first driving device drives the rotating arm to rotate and stabilize at the set speed range. At the same time, the pull rope is released by the pull rope motor so that the counterweight block moves the set distance from the position closest to the rotation center of the rotating arm to the end away from the rotation center under the action of the telescopic spring. After each position adjustment of the counterweight block, the vibration state of the main motor or impeller is re-detected by the vibration state detection device, and the current vibration detection state detection value A is obtained. n , and at the same time determine whether the counterweight has moved to the terminal limit position, and then enter step S3; if not, do not start the dynamic balance adjustment device;

[0022] S3. If A n ≥a n , and the counterweight block has not moved to the end limit position of the rotating arm, the pull rope motor continues to release the pull rope so that the counterweight block moves a set distance to the end away from the rotation center under the action of the telescopic spring, and then the vibration state of the main motor or impeller is re-detected by the vibration state detection device, and the current vibration detection state detection value is obtained. At the same time, it is determined whether the counterweight block has moved to the end limit position, and then the step is repeated. If A n ≥a n , and the counterweight has moved to the end limit position of the rotating arm, then go to step S4;

[0023] S4, determine the current vibration detection state detection value A n Vibration detection state detection value A when the counterweight is in the previous position n-1 If the size of A n ≥A n-1 , then reduce the speed of the rotating arm and return to step S2. If A n <A n-1 , then increase the rotation speed of the rotating arm and return to step S2.

[0024] In order to improve the accuracy of the dynamic balance adjustment of the impeller of the range hood, it is further improved that the counterweight block is driven by the rope motor to move successively from the position closest to the rotation center of the rotating arm to the end away from the rotation center, and the set distances are the same or decrease successively.

[0025] Compared with the existing technology, the advantages of the present invention are as follows: the range hood of the present invention adds a set of adaptive dynamic balancing adjustment devices to the fan system without changing the traditional design framework of the range hood, which dynamically balances the vibration caused by the movement of the main motor + impeller. The dynamic balancing adjustment device includes a counterweight block, which is installed on the rotating arm and can slide along the length of the rotating arm. The counterweight block and the rotating arm rotate in the opposite direction relative to the impeller through the power provided by the first drive device. The rotation torque is adjusted by adjusting the rotation radius of the counterweight block through the cooperation of the pull rope and the telescopic spring, and then the dynamic balance of the impeller is adaptively adjusted according to the specific operating conditions of the range hood, which effectively improves the vibration of the range hood. Compared with previous range hood vibration reduction solutions, it can automatically adjust according to the specific operating conditions of the range hood, with a wider range of applicable scenarios and a better experience. The dynamic balancing adjustment device can also be attached to a mature complete machine as a separate module, and is not limited by a certain model or complete machine structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the three-dimensional structure of the centrifugal fan of the range hood according to an embodiment of the present invention;

[0027] Figure 2 It is a right side view of the centrifugal fan of the range hood according to an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the three-dimensional structure of the dynamic balance adjustment device of the range hood according to an embodiment of the present invention;

[0029] Figure 4 Flowchart of a vibration reduction control method for a range hood according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0031] 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.

[0032] Figures 1-4The preferred embodiment of the range hood and the vibration reduction control method of the range hood of the present invention is shown. The range hood includes a housing, a centrifugal fan arranged in the housing, and a dynamic balancing adjustment device. The centrifugal fan includes a volute 10, an impeller 11 installed in the volute 10, and a main motor 12 that drives the impeller 11 to rotate. When the impeller 11 rotates, a negative pressure suction force is generated at the center of the fan, which draws the oil smoke below the range hood into the fan. After being accelerated by the fan, the oil smoke is collected by the volute 10 and guided to be discharged outdoors. The main body of the main motor 12 is usually installed on the rear cover plate of the volute 10 through the motor bracket 13, that is, it is located at the rear air inlet of the volute 10.

[0033] The dynamic balance adjustment device includes a mounting bracket 21, a first drive device, a second drive device, a rotating arm 22, a telescopic spring 24, a winch 23 with a rope 231 wound around it, a counterweight 25, and a vibration state detection device. The mounting bracket 21 is mounted on the rear cover of the volute 10 (of course, it can also be mounted on the main body of the main motor 12). The mounting bracket 21 includes a flat plate area in the middle and four arms connected to the middle flat plate. The flat plate structure in the middle is used to accommodate components such as the first drive device and the rotating arm 22. The four arms are used to connect to the rear cover of the volute 10. The first drive device includes a first drive motor 261, which is fixed to the flat plate area of ​​the mounting bracket 21, and the axis of the output shaft of the first drive motor 261 is collinear with the axis of the output shaft of the main motor 12. The extension direction of the rotating arm 22 is substantially perpendicular to the output shaft of the first drive motor 261. The rotating arm 22 has a first end adjacent to the first axis and a second end distal to the first axis. The first end of the rotating arm 22 is connected to the output shaft of the first drive motor 261 and is driven for rotation by the first drive motor 261. The axis of rotation about which the rotating arm 22 rotates relative to the mounting bracket 21 is referred to as the first axis. This first axis is also collinear with the axes of the main motor 12 and the first drive motor 261. The direction of rotation of the rotating arm 22 is opposite to that of the impeller 11. The second drive device, preferably a cable motor 262, is mounted on the first end of the rotating arm 22. A winch 23 for winding the cable 231 is also located at the first end of the rotating arm 22 and is connected to the output shaft of the cable motor 262. The cable motor 262 can retract or release the cable 231 by rotating forward and reverse directions. The rotating arm 22 has a limiting slide 220 extending along its length, in which a counterweight 25 slides. The limiting slideway 220 is also equipped with a telescopic spring 24, the length of which aligns with the length of the rotating arm 22. The rotating arm 22 also has a stopper 221, located adjacent to its first end, extending toward the interior of the limiting slideway 220. One end of the telescopic spring 24, facing the first end of the rotating arm 22, abuts against the stopper 221, while the other end of the telescopic spring 24 abuts against the counterweight 25, ensuring that the counterweight 25 consistently moves toward the second end of the rotating arm 22. A capstan 23, located at the first end of the rotating arm 22, faces the end of the limiting slideway 220. A pull rope 231, wound around the capstan 23, extends into the limiting slideway 220 and, after passing through the telescopic spring 24, connects to the counterweight 25. Driven by a pull rope motor 262, the capstan 23 pulls the pull rope 231, forcing the counterweight 25 toward the first axis, overcoming the elastic force of the telescopic spring 24. In this embodiment, the length of the pull rope 231 is controlled to adjust the lever arm of the counterweight 25 from the first axis, thereby adjusting the torque caused by the rotation of the counterweight 25 .Under the elastic force of the telescopic spring 24 and the tension of the pull rope 231 , the counterweight 25 can be stably maintained at the corresponding position, ensuring the accuracy of position adjustment of the counterweight 25 in the length direction of the rotating arm 22 .

[0034] The vibration state detection device is used to detect the vibration state of the main motor 12 or impeller 11. Preferably, the vibration state detection device in this embodiment includes an acceleration sensor 27 mounted on the main motor 12. The acceleration sensor 27 is electrically connected to the range hood control system. It is contemplated that the vibration state detection device is not limited to monitoring the vibration acceleration of the main motor 12. Other vibration-related parameters such as the vibration acceleration or dynamic balance of the impeller 11 can also be monitored as criteria for adjusting the dynamic balance adjustment device.

[0035] The aforementioned first drive motor 261 and rope-pulling motor 262 are also electrically connected to the range hood's control system. The range hood's control system can control the operation of the rope-pulling motor 262 based on the vibration state signal transmitted by the vibration state detection device, thereby driving the counterweight 25 to move to a suitable position, and can also control the rotational speed of the first drive motor 261 based on the vibration state signal transmitted by the vibration state detection device. Generally speaking, vibration reduction adjustment of a range hood can be achieved by adjusting the position of the counterweight 25 on the rotating arm 22 or by adjusting the rotational speed of the rotating arm 22. In this embodiment, adjusting the rotational speed of the rotating arm 22 is used as a compensation method for dynamic balancing, based on "adjusting the position of the counterweight 25 on the rotating arm 22 to achieve dynamic balancing." That is, when "adjusting the position of the counterweight 25 on the rotating arm 22 fails to effectively achieve dynamic balancing," adjustment is achieved by adjusting the rotational speed of the rotating arm 22.

[0036] See also Figure 4 This embodiment also relates to a vibration reduction control method for a range hood, comprising the following steps: after the main motor 12 of the range hood is driven, a vibration state detection device detects the vibration state of the main motor 12 or the impeller 11 and obtains a vibration state signal of the main motor 12 or the impeller 11; when the vibration detection state detection value reaches or exceeds a set threshold, a dynamic balance adjustment device is activated to sequentially adjust the position of the counterweight 25 on the rotating arm 22 and the speed range of the rotating arm 22 until the vibration detection state detection value of the main motor 12 or the impeller 11 is less than the set threshold. More specifically, see Figure 3 , the vibration reduction control method includes the following steps:

[0037] S1. The centrifugal fan is started, and the speed of the main motor 12 is stabilized in the set speed range [Sn-1, Sn] within the set time. Since different gears of the centrifugal fan correspond to different speeds, the user's requirements for the vibration of the whole machine are also different. Therefore, different vibration acceleration thresholds need to be set for different speed segments. When the whole machine is working, the speed segment of the main motor 12 is first determined, and then the acceleration threshold corresponding to the speed segment is used to determine whether to start the adaptive balancing mechanism. Among them, the vibration state of the main motor 12 or the impeller 11 sets the threshold a n The speed range of the main motor 12 is [S n-1 ,S n ] one-to-one correspondence. Specifically, the mapping relationship between the two can be obtained in advance based on experimental tests, for example:

[0038] Speed ​​range <![CDATA[S0-S1]]> <![CDATA[S1-S2]]> <![CDATA[S2-S3]]> …… <![CDATA[S n-1 -S n ]]> Motor vibration acceleration threshold <![CDATA[a1]]> <![CDATA[a2]]> <![CDATA[a3]]> …… <![CDATA[a n ]]>

[0039] S2, the vibration state detection device detects the vibration state of the main motor 12 or the impeller 11, and obtains the vibration state signal of the main motor 12 or the impeller 11 under the current working condition, and determines whether the current vibration detection state detection value A0 reaches or exceeds the set threshold value a n If so, the dynamic balancing adjustment device is started, and the first driving device drives the rotating arm 22 to rotate and stabilize in the set speed range. At the same time, the pull rope 231 is released by the pull rope motor 262, so that the counterweight 25 moves a set distance from the position closest to the rotation center of the rotating arm 22 to the end away from the rotation center under the action of the telescopic spring 24. Among them, the speed range of the rotating arm 22 when the dynamic balancing adjustment device is started can be the middle section of each speed range section of the rotating arm 22. After the position of the counterweight 25 is adjusted to the right position each time, the vibration state detection device is used to re-detect the vibration state of the main motor 12 or the impeller 11, and the current vibration detection state detection value A is obtained. n , and at the same time determine whether the counterweight 25 has moved to the terminal limit position, and then enter step S3; if not, do not start the dynamic balance adjustment device;

[0040] S3. If A n ≥a n , and the counterweight 25 has not moved to the end limit position of the rotating arm 22, the pull rope motor 262 continues to release the pull rope 231 so that the counterweight 25 moves a set distance to the end away from the rotation center under the action of the telescopic spring 24, and then the vibration state detection device is used to detect the vibration state of the main motor 12 or the impeller 11 again, and the current vibration detection state detection value is obtained. At the same time, it is determined whether the counterweight 25 has moved to the end limit position, and then the step is repeated. If A n ≥a n, and the counterweight 25 has moved to the end limit position of the rotating arm 22, then proceed to step S4;

[0041] S4, determine the current vibration detection state detection value A n The vibration detection state detection value A when the counterweight 25 is in the previous position n-1 If the size of A n ≥A n-1 , indicating that the speed of the rotating arm 22 is too high and exceeds the range of the centrifugal fan to be adjusted, the speed of the rotating arm 22 is reduced and the process returns to step S2. If A n <A n-1 , indicating that the rotation speed of the rotating arm 22 is too low and cannot meet the adjustment requirements of the centrifugal fan, the rotation speed of the rotating arm 22 is increased, and the process returns to step S2.

[0042] In the above steps, the set distances that the counterweight block 25 moves from the position closest to the rotation center of the rotating arm 22 to the end away from the rotation center can be the same or can be reduced in sequence. Preferably, the distance that the counterweight block 25 moves each time is reduced in sequence to improve the accuracy of the dynamic balance adjustment of the impeller 11 of the range hood.

[0043] Whether the counterweight 25 moves to the terminal limit position can be determined by setting a corresponding travel switch or by detecting the change in the current signal of the rope-pulling motor 262 .

[0044] Without changing the traditional range hood design framework, the range hood of this embodiment incorporates an adaptive dynamic balancing device into the fan system to dynamically balance the vibrations caused by the movement of the main motor 12 and impeller 11. The dynamic balancing device includes a counterweight 25 mounted on a rotating arm 22 and slidable along its length. Power provided by a first drive device causes the counterweight 25 and the rotating arm 22 to rotate in opposite directions relative to the impeller 11. The rotational torque is adjusted by adjusting the rotation radius of the counterweight 25 via a pull cord 231 and a telescopic spring 24. This allows for adaptive adjustment of the dynamic balance of the impeller 11 based on the specific operating conditions of the range hood, effectively improving the range hood's vibration. Compared to previous range hood vibration reduction solutions, this system can automatically adjust according to the specific operating conditions of the range hood, offering a wider range of applications and a better user experience. The dynamic balancing device can also be added as a separate module to existing range hoods, unrestricted by a specific model or overall structure.

Claims

1. A range hood comprising: A centrifugal fan comprises a volute (10), an impeller (11) rotatably arranged in the volute (10), and a main motor (12) for driving the impeller (11) to rotate; It is characterized by also including: A dynamic balancing adjustment device comprises a mounting bracket (21) fixed relative to the volute (10) and a rotating arm (22) driven by a first driving device and arranged on the mounting bracket (21), wherein the rotating axis of the rotating arm (22) relative to the mounting bracket (21) is recorded as a first axis, the first axis is collinear with the axis of the main motor (12), the rotation direction of the rotating arm (22) is opposite to the rotation direction of the impeller (11), the rotating arm (22) has a first end adjacent to the first axis and a second end away from the first axis, the rotating arm (22) is further defined on the rotating arm (22) and is arranged along its length direction. A limiting slideway (220) and a matching member provided with a sliding constraint in the limiting slideway (220) are provided. The counterweight (25) is provided with a telescopic spring (24) in the limiting slideway (220), and the telescopic spring (24) acts on the counterweight (25) and makes the counterweight (25) always have a tendency to move toward the second end of the rotating arm (22). The first end of the rotating arm (22) is also provided with a winch (23) for winding a pull rope (231) and a pull rope motor (262) for driving the winch (23) to rotate. The end of the pull rope (231) wound on the winch (23) extends into the limiting slideway (220) and is connected to the counterweight (25). Driven by the pull rope motor (262), the counterweight (25) can overcome the elastic force of the telescopic spring (24) and approach the first axis.

2. The range hood according to claim 1, characterized in that: The rotating arm (22) also has a limit stop portion (221) extending toward the interior of the limit slideway (220) at a position adjacent to the first end thereof, and one end of the telescopic spring (24) facing the first end of the rotating arm (22) abuts against the limit stop portion (221).

3. The range hood according to claim 1, wherein: The pull rope (231) passes through the telescopic spring (24) and is connected to the counterweight (25).

4. The range hood according to claim 1, wherein: It also includes a vibration state detection device for detecting the vibration state of the main motor (12) or the impeller (11). The vibration state detection device and the pull-rope motor (262) are electrically connected to the control system of the range hood. The control system of the range hood can control the movement of the pull-rope motor (262) according to the vibration state signal transmitted by the vibration state detection device, thereby driving the counterweight block (25) to move to a suitable position.

5. The range hood according to claim 4, characterized in that: The vibration state detection device includes an acceleration sensor (27) which is arranged on the main body of the main motor (12).

6. The range hood according to any one of claims 1 to 5, characterized in that: The first driving device comprises a first driving motor (261), the main body of the first driving motor (261) is arranged on the mounting bracket (21), and the axis of the first driving motor (261) is collinear with the axis of the main motor (12), and the end of the rotating arm (22) is connected to the output shaft of the first driving motor (261), so that it can rotate under the drive of the first driving motor (261).

7. The range hood according to claim 6, characterized in that: It also includes a vibration state detection device for detecting the vibration state of the main motor (12) or the impeller (11); the vibration state detection device and the first drive motor (261) are both electrically connected to the control system of the range hood; the control system of the range hood can control the rotation speed of the first drive motor (261) according to the vibration state signal transmitted by the vibration state detection device.

8. A vibration reduction control method for a range hood according to any one of claims 1 to 7, characterized in that The following steps are involved: After the main motor (12) of the range hood is driven, the vibration state detection device detects the vibration state of the main motor (12) or the impeller (11) and obtains a vibration state signal of the main motor (12) or the impeller (11); when the vibration detection state detection value reaches or exceeds a set threshold, the dynamic balance adjustment device is activated to sequentially adjust the position of the counterweight (25) on the rotating arm (22) and the speed range of the rotating arm (22) until the vibration detection state detection value of the main motor (12) or the impeller (11) is less than the set threshold.

9. The range hood vibration reduction control method according to claim 8, characterized in that The following steps are involved: S1. The centrifugal fan starts, and the speed of the main motor (12) is stabilized within the set speed range within the set time [S n-1 ,S n ], the main motor (12) is in different speed ranges [S n-1 ,S n ], the vibration state of the main motor (12) or the impeller (11) sets the threshold value a n Also different, wherein the vibration state setting threshold value an of the main motor (12) or the impeller (11) is related to the speed range [S n-1 ,S n ] one-to-one correspondence; S2. The vibration state detection device detects the vibration state of the main motor (12) or the impeller (11), obtains the vibration state signal of the main motor (12) or the impeller (11) under the current working condition, and determines whether the current vibration detection state detection value A0 reaches or exceeds the set threshold value a. n If yes, the dynamic balance adjustment device is started, the first driving device drives the rotating arm (22) to rotate and stabilize in the set speed range, and at the same time, the pull rope (231) is released by the pull rope motor (262), so that the counterweight (25) moves a set distance from the position closest to the rotation center of the rotating arm (22) to the end away from the rotation center under the action of the telescopic spring (24). After each position adjustment of the counterweight (25) is in place, the vibration state of the main motor (12) or the impeller (11) is re-detected by the vibration state detection device, and the current vibration detection state detection value A is obtained. n , and at the same time determine whether the counterweight (25) has moved to the terminal limit position, and then enter step S3; if not, do not start the dynamic balance adjustment device; S3. If A n ≥a n , and the counterweight (25) has not moved to the terminal limit position of the rotating arm (22), the pull rope motor (262) continues to release the pull rope (231) so that the counterweight (25) moves a set distance to one end away from the rotation center under the action of the telescopic spring (24), and then the vibration state of the main motor (12) or the impeller (11) is re-detected by the vibration state detection device, and the current vibration detection state detection value is obtained, and at the same time, it is determined whether the counterweight (25) has moved to the terminal limit position, and then the step is repeated. If A n ≥a n , and the counterweight (25) has moved to the end limit position of the rotating arm (22), then proceed to step S4; S4, determine the current vibration detection state detection value A n The vibration detection state detection value A when the counterweight (25) is in the previous position state n-1 If the size of A n ≥A n-1 , then reduce the rotation speed of the rotating arm (22) and return to step S2. If A n <A n-1 , then increase the rotation speed of the rotating arm (22) and return to step S2.

10. The range hood vibration reduction control method according to claim 9, characterized in that: The counterweight (25) is driven by the rope-pulling motor to move sequentially from a position closest to the rotation center of the rotating arm (22) to an end away from the rotation center, and the set distances are the same or decrease sequentially.

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