A fan system for a range hood and a range hood

Abstract

The application relates to a fan system for an extractor hood and the extractor hood. The fan system comprises a volute, an impeller, a main motor, an auxiliary motor, a switch device, a sliding piece with a sliding contact point and a switch disc assembly. The output shaft of the main motor is connected with the impeller. The output shaft of the auxiliary motor is directly or indirectly connected with the output shaft of the main motor. The switch device is arranged in the power supply circuit of the auxiliary motor. The sliding piece is arranged on the output shaft of the main motor and can slide between the fixed contact points at different positions of the switch disc assembly with the change of the rotating speed of the output shaft of the main motor. The sliding piece can be electrically connected with the different fixed contact points on the switch disc assembly with the change of the sliding position, so that the auxiliary motor is switched between the first rotating state with the same rotating direction as the main motor and the second rotating state with the opposite rotating direction of the main motor. The fan system has low cost and can realize the accurate and reliable control of the motor kept in the optimal rotating speed range.

Description

Technical Field

[0001] This invention relates to the field of range hood technology, and in particular to a fan system for a range hood and a range hood. Background Technology

[0002] Range hoods have become an indispensable kitchen appliance in modern homes. They operate on the principles of fluid dynamics, using a fan system installed inside to draw in and exhaust cooking fumes, and filtering out some grease particles with a filter. Household range hoods typically use AC motors to drive their fan systems, which offer multiple speed settings. For example, Chinese patent application number 201520803334.2 discloses a range hood with an automatic pressurization function. This includes a range hood casing, a panel, a volute, and a blower unit. The volute houses a turbine driven by a motor, and an exhaust pipe connects to the flue. A check valve is installed between the exhaust pipe and the flue, or between the exhaust pipe and the volute. The motor is electrically connected to a control system and a control panel on the casing. The control system also includes a wind pressure detector, which automatically adjusts the motor speed based on the detection results. The motor is an AC motor, and the wind pressure detector is a current sensor mounted on the motor.

[0003] Based on the working principle of AC motors, under the same voltage, the performance of a motor varies under different operating conditions, and the efficiency at the operating point also differs significantly. Under certain conditions, the motor's efficiency may be low, causing it to stop working; this occurs when the motor's operating speed deviates from its optimal speed range. Deviating from the optimal speed range has two disadvantages: 1. Low efficiency: Operating outside the highest efficiency point, the motor's performance cannot be fully utilized, resulting in significant energy loss; 2. High heat generation: Deviating from the most efficient point, electrical energy cannot be efficiently converted into kinetic energy, resulting in energy loss as heat, leading to high motor heat generation and further reducing motor efficiency.

[0004] To address the aforementioned technical problems, Chinese invention patent application CN202111531225.6 (publication number CN114233654A) discloses a fan system, a range hood, and a control method thereof. The fan system includes a volute, an impeller housed within the volute, and a drive mechanism for driving the impeller's rotation. The drive mechanism includes a motor and an impeller shaft. The motor has an output shaft, and the impeller shaft is fixedly connected to the impeller, serving as the impeller's rotation shaft. The drive mechanism also includes a first kinematic pair, comprising a first kinematic pair component and a second kinematic pair component. The first kinematic pair component is fixedly mounted on one of the output shaft and the impeller shaft. The second kinematic pair component can move relative to the first kinematic pair component, thereby changing the transmission ratio of the first kinematic pair. The second kinematic pair component is connected to the other of the output shaft and the impeller shaft via the second kinematic pair. This patent application, by setting a kinematic pair with a variable transmission ratio, changes the relative speed between the impeller and the motor in real time, keeping the motor near its highest efficiency point, thus improving efficiency and reducing heat generation.

[0005] The fan system in the aforementioned patent application also has certain shortcomings. The fan system requires additional speed and torque sensors, power sensors, etc., to detect changes in motor speed and motor input power, and then change the transmission ratio of the kinematic pair to keep the motor near its highest efficiency point. The installation of the aforementioned sensors increases production costs, and the sensors are easily affected by oily environments, which reduces their detection accuracy and makes it difficult to achieve precise and reliable control of the motor to keep it in the optimal speed range. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a low-cost fan system for a range hood that can achieve precise and reliable control of the motor to keep it within the optimal speed range, in light of the current state of the prior art.

[0007] The second technical problem to be solved by the present invention is to provide a range hood that uses the above-mentioned fan system, in view of the current state of the prior art.

[0008] The technical solution adopted by this invention to solve the first technical problem is: a fan system for a range hood, comprising:

[0009] The volute has an air inlet;

[0010] The impeller is rotatably disposed within the volute.

[0011] The main motor is fixed relative to the volute, and its output shaft is connected to the impeller, thereby driving the impeller to rotate;

[0012] An auxiliary motor is fixed relative to the volute, and its output shaft is directly or indirectly connected to the output shaft of the main motor.

[0013] A switching device, disposed in the power supply circuit of the auxiliary motor, includes a switch panel assembly with two sets of fixed electrical contacts and a slider with sliding electrical contacts. The slider is disposed on the output shaft of the main motor and can slide relative to the switch panel assembly between the fixed electrical contacts at different positions as the rotational speed of the output shaft of the main motor changes. The slider can electrically connect with different fixed electrical contacts on the switch panel assembly as its sliding position changes, thereby enabling the auxiliary motor to switch between a first rotational state in the same direction as the main motor and a second rotational state in the opposite direction to the main motor.

[0014] To simplify the structure of the aforementioned switching device and enable commutation (rotation direction) control of the auxiliary motor when the main motor is above or below a set speed, the switch assembly includes a first switch disk and a second switch disk spaced apart axially on the output shaft of the main motor. The first switch disk has a first annular conductive unit and a second annular conductive unit spaced apart radially on its sidewall facing the second switch disk. The second switch disk has a third annular conductive unit and a fourth annular conductive unit spaced apart radially on its sidewall facing the first switch disk. The first annular conductive unit and the second annular conductive unit on the first switch disk correspond to the third annular conductive unit and the fourth annular conductive unit on the second switch disk, respectively.

[0015] The output shaft of the main motor is provided with a fixing pin that extends radially outward and is located between the first switch disk and the second switch disk. The sliding member is slidably disposed on the fixing pin. The sliding member can move between a first position and a second position along the length direction of the fixing pin as the rotational speed of the output shaft of the main motor changes. When the sliding member moves to the first position, the sliding contact on the sliding member electrically connects the first annular conductive unit on the first switch disk to the third annular conductive unit on the second switch disk. When the sliding member moves to the second position, the sliding contact on the sliding member electrically connects the second annular conductive unit on the first switch disk to the fourth annular conductive unit on the second switch disk.

[0016] To make the position control of the slider on the fixed pin more precise and reliable, it also includes:

[0017] An elastic element acts on the sliding element, causing the sliding element to always tend to move along the fixed pin toward the position of the output shaft of the main motor.

[0018] The aforementioned elastic element can employ various existing technologies, including compression springs, torsion springs, leaf springs, and other elastic components. However, for better coordination with the sliding element that slides on the fixed pin, the elastic element is a tension spring sleeved on the fixed pin and located on the side of the sliding element facing the output shaft of the main motor. It is conceivable that the elastic element could also be a compression spring, which could similarly be sleeved on the fixed pin and located on the side away from the output shaft of the main motor.

[0019] To ensure reliable electrical connection between the slider and the two switch panels when the slider slides to different positions, the first annular conductive unit includes a first positive annular conductive sheet and a first negative annular conductive sheet arranged radially at intervals; the second annular conductive unit includes a second positive annular conductive sheet and a second negative annular conductive sheet arranged radially at intervals; the third annular conductive unit includes a third positive annular conductive sheet and a third negative annular conductive sheet arranged radially at intervals; and the fourth annular conductive unit includes a fourth positive annular conductive sheet and a fourth negative annular conductive sheet arranged radially at intervals. The first positive annular conductive sheet is opposite to the third positive annular conductive sheet, the first negative annular conductive sheet is opposite to the third negative annular conductive sheet, the second positive annular conductive sheet is opposite to the fourth negative annular conductive sheet, and the second negative annular conductive sheet is opposite to the fourth positive annular conductive sheet.

[0020] To further improve the reliable electrical connection between the sliding contact of the slider and the fixed contact on the switch panel, the slider is an integrally annular sliding sleeve. The outer peripheral wall of the sliding sleeve is provided with a first conductive ring and a second conductive ring spaced apart along the axial direction of the sliding sleeve. The first conductive ring and the second conductive ring together constitute the sliding contact of the slider.

[0021] In order to make reasonable use of the airflow power at the secondary air inlet of the volute, a power generation device is also included. The power generation device includes a generator and an auxiliary fan blade located at the air inlet of the volute and rotating under the drive of the airflow at the air inlet. The auxiliary fan blade is connected to the power input shaft of the generator, and the switching device is located in the circuit between the generator and the auxiliary motor.

[0022] When the temperature of the main motor body is within a suitable temperature range, the control circuit of the auxiliary motor does not need to be turned on. However, when the temperature of the main motor body is too high, the speed of the main motor can be limited by the forward and reverse reversing operation of the auxiliary motor, thus achieving precise control of the entire fan system. Therefore, in order to take the temperature factor of the main motor body into account and achieve precise control, a support assembly is also included. At least one of the first switch panel and the second switch panel is disposed on the support assembly. The support assembly includes a heat-conducting component that can contact the main motor body and a shape memory element that is in contact with the heat-conducting component and changes shape when heated. The shape memory element can drive the first switch panel or the second switch panel disposed on the support assembly to move closer or further away as its temperature changes, thereby connecting or disconnecting the sliding contact on the sliding component with the fixed contact on the switch panel assembly.

[0023] To precisely adjust the distance between the first and second switch disks, the system further includes a support disk fixed relative to the volute and at least two connecting posts connected to the support disk and spaced apart circumferentially along the support disk. Each connecting post extends substantially along the axis of the output shaft of the main motor. Each connecting post is provided with the aforementioned shape memory element, which changes the overall length of the connecting post according to its heating temperature. One of the first and second switch disks is fixed relative to the support disk, while the other is connected to each of the connecting posts.

[0024] To facilitate the installation of the bracket assembly, the shape memory element is an annular pad that is circular in shape as a whole. Each of the connecting posts includes a first post and a second post. The first post and the second post are respectively connected to two opposite side walls of the annular pad and extend in the same straight line.

[0025] In order to achieve good heat conduction between the main motor and the annular pad, the heat conduction element is a support arm structure that extends from the annular pad toward the main body of the main motor and contacts the main body of the main motor.

[0026] Generally, both the first and second switch disks can be movable and adjustable by a shape memory element. However, in order to simplify the structure of the support assembly and ensure the accuracy of the distance adjustment between the two switch disks, the second switch disk is connected to the support disk by at least two first support rods spaced apart along the circumference of the second switch disk, and the first switch disk is connected to each of the connecting columns.

[0027] To facilitate the placement of components such as auxiliary fan blades, auxiliary motors, switching devices, and power generation devices, and to avoid affecting the overall air intake of the fan system, the volute has two air inlets: a main air inlet and a secondary air inlet. The main motor is a dual-output shaft motor, which has a first shaft extending toward the main air inlet and a second shaft extending toward the secondary air inlet. The auxiliary fan blades, auxiliary motor, switching devices, and power generation devices are all located at the secondary air inlet of the volute.

[0028] To make the overall structure more compact after the auxiliary motor, generator and other components are installed, the auxiliary motor is located on the side wall of the support plate facing the main motor in the middle, and the output shaft of the auxiliary motor is connected to the second shaft of the main motor. The generator is located on the side wall of the support plate away from the main motor in the middle.

[0029] In order to achieve a fixed connection between the support plate and the volute, a motor bracket for fixing the main motor is provided at the secondary air inlet of the volute, and the outer periphery of the support plate is connected to the motor bracket.

[0030] The technical solution adopted by the present invention to solve the second technical problem is a range hood, including a fan system, wherein the fan system adopts the above-mentioned fan system for range hoods.

[0031] Compared with existing technologies, the advantages of this invention are as follows: The fan system of this invention utilizes the auxiliary fan blades to power the air intake at the air inlet. A generator converts the kinetic energy into electrical energy to power the auxiliary motor. Furthermore, a sliding member with sliding electrical contacts can move to different positions according to the speed of the main motor (i.e., different centrifugal forces), thereby connecting with different fixed electrical contacts on the switch panel assembly. This enables switching control of the auxiliary motor's forward and reverse rotation, allowing the auxiliary motor to accelerate / decelerate the main motor to adjust the operating efficiency range. This method uses the centrifugal force on the sliding member itself as a switching condition, achieving real-time monitoring of the fan system's impeller speed. The switching method is more stable and reliable. Compared with the sensor-based method in existing technologies, it is lower in cost and can more accurately maintain the main motor within the optimal speed range. On the other hand, the fan system of this invention not only provides power input to the auxiliary motor through the auxiliary fan blades but also pre-rotates the air intake of the fan system, improving airflow stability. In the preferred solution, the temperature factor of the main motor body (whether it is higher than the set temperature) is taken into account as another condition for the switching device to control the on / off of the auxiliary motor circuit. This further ensures the accuracy of the overall control of the fan system, so that the main motor always works in a high efficiency range, avoids the main motor from stopping, and ensures the working stability of the range hood. Attached Figure Description

[0032] Figure 1This is a three-dimensional structural diagram of a range hood according to an embodiment of the present invention;

[0033] Figure 2 This is a three-dimensional structural diagram of the rear part of the range hood according to an embodiment of the present invention (the rear panel of the casing is omitted).

[0034] Figure 3 This is a three-dimensional structural diagram of the fan system according to an embodiment of the present invention;

[0035] Figure 4 This is a three-dimensional structural diagram of the fan system according to an embodiment of the present invention, omitting components such as the volute and impeller.

[0036] Figure 5 for Figure 4 A three-dimensional structural diagram after removing the motor bracket;

[0037] Figure 6 for Figure 5 Exploded view;

[0038] Figure 7 for Figure 5 A sectional view taken along the axial direction of the main motor;

[0039] Figure 8 for Figure 7 Enlarged view of point A in the image;

[0040] Figure 9 This is a three-dimensional structural diagram of the second switch disk according to an embodiment of the present invention;

[0041] Figure 10 This is a three-dimensional structural diagram of a unit component consisting of a first switch disk, connecting column, shape memory element, heat-conducting component, etc., according to an embodiment of the present invention.

[0042] Figure 11 for Figure 10 A three-dimensional structural diagram of the unit components after they have been installed onto the support plate;

[0043] Figure 12 for Figure 11 Enlarged view of point A in the image;

[0044] Figure 13 for Figure 6 Enlarged view of point A in the image;

[0045] Figure 14 This is a speed-efficiency curve for an AC asynchronous motor. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0047] The specification and claims of this invention use terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," to describe various exemplary structural parts and elements of the invention. However, these terms are used herein merely for ease of explanation and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0048] like Figures 1-13 This illustration shows a preferred embodiment of the present invention. The range hood includes a housing 80 and a fan system, which is a centrifugal fan, disposed within the housing 80. An air intake is provided on the front side wall of the housing 80, opposite to the main air inlet 101 of the centrifugal fan inside the housing 80. A deflectable panel 81 is also provided on the front side of the housing 80. This panel 81 is rotatably connected to the housing 80 with its upper side as the center of rotation, and can open or close the air intake of the housing 80. Specifically, for aesthetic purposes, when closed, the panel 81 can substantially cover the entire front side wall area of ​​the housing 80.

[0049] The centrifugal fan in this embodiment includes a volute 10, an impeller 11, a main motor 12, an auxiliary motor 21, an auxiliary fan blade 32, a power generation device, and a switching device.

[0050] The volute 10 has a main air inlet 101 and a secondary air inlet 102 on its front and rear side walls, respectively. The main motor 12 is an AC motor, and its main body is connected to the outer periphery of the secondary air inlet 102 of the volute 10 via a motor bracket 13. In this embodiment, the main motor 12 is a dual-output shaft motor, which has a first shaft 121 extending toward the main air inlet 101 and a second shaft 122 extending toward the secondary air inlet 102. The first shaft 121 of the main motor 12 is connected to the impeller 11, thereby driving the impeller 11 to rotate.

[0051] like Figure 3 As shown, a support plate 71 is also provided at the secondary air inlet 102 of the volute 10. This support plate 71 is connected to the motor bracket 13 by a plurality of second support rods 76 spaced apart in the circumferential direction. Specifically, each second support rod 76 is connected to the part where the motor bracket 13 connects to the main body of the main motor 12. More specifically, in order to avoid affecting the air intake of the secondary air inlet 102, the support plate 71 has a hollow structure, which has an annular frame as the outer perimeter and a solid plate in the middle. The annular frame and the solid plate are connected by a plurality of ribs.

[0052] Both the generator 31 and the auxiliary motor 21 are mounted on a solid plate in the middle of the support plate 71. The generator 31 is mounted on the side wall of the solid plate away from the main motor 12, and the auxiliary motor 21 is mounted on the side wall of the solid plate facing the main motor 12. An auxiliary fan is also provided in the power input of the generator 31. This auxiliary fan rotates under the influence of the airflow entering the secondary air inlet 102 of the volute 10, thereby providing power for the generator 31 to generate electricity. In this embodiment, the auxiliary motor 21 is a motor capable of rotating in both directions. The output shaft of the auxiliary motor 21 is connected to the second shaft 122 of the main motor 12. The auxiliary motor 21 is electrically connected to the generator 31, and the generator 31 provides electrical energy for the operation of the auxiliary motor 21. The circuit between the auxiliary motor 21 and the generator 31 can be switched using a switching device to allow the auxiliary motor 21 to rotate in both directions, thereby using the auxiliary motor 21 to accelerate / decelerate the main motor 12 to adjust the working efficiency range.

[0053] The switching device includes a switch panel assembly, a slider 42, a fixing pin 41, and an elastic element 43.

[0054] The switch panel assembly includes a first switch panel 50 and a second switch panel 60 spaced apart axially along the output shaft of the main motor 12. The first switch panel 50 is connected to a support panel 71 via a bracket assembly 70, and the second switch panel 60 is connected to the support panel 71 via a plurality of first support rods 75 spaced apart circumferentially. The first support rods 75 are rigid rods, so the distance between the second switch panel 60 and the support panel 71 is not adjustable.

[0055] The distance between the first switch disk 50 and the support disk 71 (i.e., the distance between the first switch disk 50 and the second switch disk 60) can be automatically adjusted by the bracket assembly 70 according to the temperature of the main motor 12 body. Specifically, the bracket assembly 70 includes connecting posts 72, shape memory elements 73, and heat-conducting components 74. Multiple connecting posts 72 are spaced circumferentially along the first switch disk 50, and each connecting post 72 is parallel to the output shaft of the main motor 12. The shape memory element 73 can be made of shape memory alloy material and is an annular pad with an overall ring shape. Correspondingly, each connecting post 72 includes a first post 721 and a second post 722 extending on the same straight line. The first post 721 and the second post 722 are respectively connected to two opposite sidewalls of the annular pad. Specifically, as shown... Figure 8As shown, the first post 721 connects the first switch disk 50 and the annular pad, and the second post 722 connects the annular pad and the support disk 71. The heat-conducting element 74 is a support arm structure extending from the annular pad toward the main body of the main motor 12. The end of the heat-conducting element 74 is always in contact with the main body of the main motor 12, thereby enabling timely and rapid transfer of heat from the main body of the main motor 12 to the annular pad. Since the shape and size of the shape memory element 73 can change with its heating temperature, the overall length of the connecting post 72 will also change accordingly. When the shape memory element 73 is above the set temperature, the overall length of the connecting post 72 will increase accordingly, and when the shape memory element 73 is below the set temperature, the connecting post 72 will return to its initial length.

[0056] Both the first switch disk 50 and the second switch disk 60 have clearance holes (not shown) in their middle portions for the second shaft 122 of the main motor 12 and the output shaft of the auxiliary motor 21 to pass through. The first switch disk 50 has a first annular conductive unit 51 and a second annular conductive unit 52 arranged radially at intervals on its sidewall facing the second switch disk 60. The second switch disk 60 has a third annular conductive unit 61 and a fourth annular conductive unit 62 arranged radially at intervals on its sidewall facing the first switch disk 50. The first annular conductive unit 51 and the second annular conductive unit 52 on the first switch disk 50 are axially opposite to the third annular conductive unit 61 and the fourth annular conductive unit 62 on the second switch disk 60, and correspond one-to-one. More specifically, the first annular conductive unit 51 of the first switch disk 50 includes a first positive annular conductive sheet 511 and a first negative annular conductive sheet 512 arranged radially at intervals, and the second annular conductive unit 52 includes a second positive annular conductive sheet 521 and a second negative annular conductive sheet 522 arranged radially at intervals. The third annular conductive unit 61 of the second switch disk 60 includes a third positive annular conductive sheet 611 and a third negative annular conductive sheet 612 arranged radially at intervals. The fourth annular conductive unit 62 includes a fourth positive annular conductive sheet 621 and a fourth negative annular conductive sheet 622 arranged radially at intervals. Specifically, the first positive annular conductive sheet 511 of the first switch disk 50 is opposite to the third positive annular conductive sheet 611 of the second switch disk 60; the first negative annular conductive sheet 512 of the first switch disk 50 is opposite to the third negative annular conductive sheet 612 of the second switch disk 60; the second positive annular conductive sheet 521 of the first switch disk 50 is opposite to the fourth negative annular conductive sheet 622 of the second switch disk 60; and the second negative annular conductive sheet 522 of the first switch disk 50 is opposite to the fourth positive annular conductive sheet 621 of the second switch disk 60. The first annular conductive unit 51 of the first switch disk 50 and the third annular conductive unit 61 of the second switch disk 60 constitute a set of fixed electrical contacts of the switch disk assembly. The second annular conductive unit 52 of the first switch disk 50 and the fourth annular conductive unit 62 of the second switch disk 60 constitute another set of fixed electrical contacts of the switch disk assembly.

[0057] Corresponding to the switch panel assembly, a radially outwardly extending fixing pin 41 is provided on the second shaft 122 of the main motor 12, located between the first switch panel 50 and the second switch panel 60. To ensure the dynamic balance of the rotation of the second shaft 122 of the main motor 12, two fixing pins 41 are symmetrically arranged with the second shaft 122 as the center of symmetry. Each fixing pin 41 is provided with a sliding member 42 and an elastic member 43. Specifically, the sliding member 42 is an integrally annular sliding sleeve. The outer peripheral wall of the sliding sleeve is provided with a first conductive ring 421 and a second conductive ring 422 spaced apart along the axial direction of the sliding sleeve. The first conductive ring 421 and the second conductive ring 422 together constitute the sliding contact of the sliding member. The sliding contact on the sliding member 42 is always in contact with the surface of the second switch panel 60 (the side wall with the annular conductive sheet).

[0058] In this embodiment, the elastic element 43 is preferably a retaining spring fitted onto the fixing pin 41. This spring is located on the side of the fixing pin 41 where the sliding element 42 faces the output shaft of the main motor 12. When the rotational speed of the second shaft 122 of the main motor 12 increases, the sliding element can overcome the elastic force of the spring and move outward along the positioning pin. When the rotational speed of the second shaft 122 of the main motor 12 decreases, the sliding element can move inward along the positioning pin under the action of the elastic force of the spring. Thus, the position of the sliding element 42 on the positioning pin can be dynamically adjusted under the combined action of centrifugal force and the elastic force of the spring.

[0059] The aforementioned sliding member 42 can move between a first position and a second position along the length direction of the fixed pin 41 as the rotational speed of the output shaft of the main motor 12 changes. Specifically, when the rotational speed of the output shaft of the main motor 12 is lower than the set speed (in the low speed range), the sliding member 42 moves to the first position. At this time, the first conductive ring 421 on the sliding member 42 connects the first positive annular conductive piece 511 on the first switch disk 50 with the third positive annular conductive piece 611 on the second switch disk 60, and the second conductive ring 422 on the sliding member 42 connects the first negative annular conductive piece 512 on the first switch disk 50 with the third negative annular conductive piece 612 on the second switch disk 60. The current between the auxiliary motor 21 and the generator 31 is connected, and the rotational direction of the output shaft of the auxiliary motor 21 is the same as that of the main motor 12, which plays a supporting role and achieves the purpose of increasing the rotational speed of the main motor 12. When the output shaft speed of the main motor 12 is higher than the set speed (in the high speed range), the sliding member 42 moves to the second position. At this time, the first conductive ring 421 on the sliding member 42 connects the second positive annular conductive piece 521 on the first switch disk 50 with the fourth negative annular conductive piece 622 on the second switch disk 60. The second conductive ring 422 on the sliding member 42 connects the second negative annular conductive piece 522 on the first switch disk 50 with the fourth positive annular conductive piece 621 on the second switch disk 60. The current between the auxiliary motor 21 and the generator 31 is connected. However, the rotation direction of the output shaft of the auxiliary motor 21 is opposite to the rotation direction of the main motor 12, which increases the load and reduces the speed of the main motor 12.

[0060] In this embodiment, the auxiliary motor 21 is used to accelerate / decelerate the main motor 12, thereby adjusting the working efficiency range of the main motor 12. This method uses the centrifugal force on the sliding member 42 itself as the switching condition to realize real-time monitoring of the speed of the impeller 11 of the fan system. The switching method is more stable and reliable. Compared with the method of setting sensors in the prior art, it has a lower cost and can keep the main motor 12 more accurately within the optimal speed range.

[0061] Combination Figure 14 The speed-efficiency curve of the AC asynchronous motor is used to illustrate the control process of the range hood fan system in this embodiment:

[0062] When the main motor 12 speed is low, such as below Figure 14When the speed is at midpoint A, the efficiency will be too low, and the temperature of the main motor 12 will rise sharply. When the temperature approaches t1, where t1 is the temperature value that is different from the motor stop temperature by a set value, the heat of the main motor 12 is conducted to the annular pad through the heat-conducting component 74. The annular pad deforms due to heat, the connecting column 72 extends, and pushes the first switch disk 50 away from the support disk 71 (that is, closer to the second switch disk 60), thereby realizing the contact between the fixed electrical contact on the first switch disk 50 and the sliding electrical contact on the sliding component 42. Based on this, when the speed of the main motor 12 is lower than the set value V1, the sliding contact on the sliding member 42 will be in the first position (that is, the position close to the center of the switch panel assembly), so that the first annular conductive unit 51 on the first switch panel 50 is electrically connected to the third annular conductive unit 61 on the second switch panel 60. The auxiliary fan blade 32 drives the generator 31 to rotate under the action of the external wind to generate current, which flows through the rectifier circuit to the auxiliary motor 21. The auxiliary motor 21 provides auxiliary power to the main motor 12, thereby increasing the speed of the main motor 12 to be higher than v1, so as to achieve the purpose that the working speed of the main motor 12 is always higher than v1.

[0063] Conversely, when the main motor 12 rotates at a higher speed, such as above... Figure 14 When the rotational speed is at the midpoint B, the efficiency will be too low, and the temperature of the main motor 12 will rise sharply. When the temperature approaches t1, the main motor 12 will also conduct heat to the annular pad through the heat-conducting component 74. The annular pad will deform due to heat, the connecting column 72 will extend, and push the first switch disk 50 away from the support disk 71 (that is, closer to the second switch disk 60), thereby realizing the contact between the fixed electrical contact on the first switch disk 50 and the sliding electrical contact on the sliding component 42. Based on this, when the rotational speed is higher than the set value v2, the sliding contact on the sliding member 42 will be in the second position (i.e., a position away from the center of the switch panel assembly), realizing the electrical connection between the second annular conductive unit 52 on the first switch panel 50 and the fourth annular conductive unit 62 on the second switch panel 60. This allows the auxiliary fan blade 32 to drive the generator 31 to rotate under the action of external wind, generating current. This current flows through the rectifier circuit to the auxiliary motor 21. At this time, the auxiliary motor 21 rotates in the opposite direction to the main motor 12, increasing the load on the main motor 12 and thus reducing the rotational speed of the main motor 12, ensuring that the rotational speed of the main motor 12 is always below v2. Therefore, through the above-mentioned adjustment and control, when the temperature is higher than t1, the fan system can ensure that the main motor 12 always operates in a higher efficiency range, preventing the main motor 12 from stopping and ensuring the stability of the range hood.

[0064] The advantages of the range hood fan system in this embodiment are as follows:

[0065] 1. This fan system can prevent shutdown due to overheating of the main motor 12, thereby improving the stability of the fan system, ensuring the function of the air intake system, and enhancing the smoke extraction capacity of the range hood.

[0066] 2. The fan system can control the speed of the main motor 12 according to the temperature status of the main motor 12, so that when the temperature of the main motor 12 is higher than a certain limit, the speed of the main motor 12 is limited to always remain within a specific range.

[0067] 3. This fan system uses the fan's own air intake as power to achieve 12 speed control of the main motor, and the control method is simple and stable.

[0068] 4. The fan system uses the centrifugal force on the sliding part 42 itself as the switching power, which is ingenious. In particular, the fan system uses the centrifugal force on the sliding part 42 itself as the switching condition to realize real-time monitoring of the speed of the impeller 11 of the fan system. The switching method is stable and reliable.

[0069] 5. The fan system, through the auxiliary fan blades 32 located at the secondary air inlet 102, not only realizes the power input to the auxiliary motor 21, but also pre-rotates the air intake of the fan system, thereby improving the stability of airflow.

Claims

1. A fan system for a range hood, comprising: The volute (10) has an air inlet; The impeller (11) is rotatably disposed within the volute (10); The main motor (12) is fixed relative to the volute (10), and its output shaft is connected to the impeller (11), thereby driving the impeller (11) to rotate; Its features also include: An auxiliary motor (21) is fixed relative to the volute (10), and its output shaft is directly or indirectly connected to the output shaft of the main motor (12). The switching device is located in the power supply circuit of the auxiliary motor (21), including a switch panel assembly with two sets of fixed electrical contacts and a slider (42) with sliding electrical contacts. The slider (42) is located on the output shaft of the main motor (12) and can slide relative to the switch panel assembly between the fixed electrical contacts at different positions as the rotation speed of the output shaft of the main motor (12) changes. The slider (42) can be electrically connected to different fixed electrical contacts on the switch panel assembly as its sliding position changes, thereby allowing the auxiliary motor (21) to switch between a first rotation state with the same rotation direction as the main motor (12) and a second rotation state with the opposite rotation direction to the main motor (12). The switch assembly includes a first switch disk (50) and a second switch disk (60) spaced apart axially on the output shaft of the main motor (12). The first switch disk (50) has a first annular conductive unit (51) and a second annular conductive unit (52) arranged radially spaced on the side wall facing the second switch disk (60). The second switch disk (60) has a third annular conductive unit (61) and a fourth annular conductive unit (62) arranged radially spaced on the side wall facing the first switch disk (50). The first annular conductive unit (51) and the second annular conductive unit (52) on the first switch disk (50) correspond to the third annular conductive unit (61) and the fourth annular conductive unit (62) on the second switch disk (60), respectively. The output shaft of the main motor (12) is provided with a fixing pin (41) extending radially outward and located between the first switch disk (50) and the second switch disk (60). The sliding member (42) is slidably disposed on the fixing pin (41). The sliding member (42) can move along the length direction of the fixing pin (41) between a first position and a second position as the rotational speed of the output shaft of the main motor (12) changes. When the sliding member (42) moves to the first position, the sliding contact on the sliding member (42) electrically connects the first annular conductive unit (51) on the first switch disk (50) with the third annular conductive unit (61) on the second switch disk (60). When the sliding member (42) moves to the second position, the sliding contact on the sliding member (42) electrically connects the second annular conductive unit (52) on the first switch disk (50) with the fourth annular conductive unit (62) on the second switch disk (60).

2. The fan system for a range hood according to claim 1, characterized in that... Also includes: An elastic element (43) acts on the sliding element (42) and causes the sliding element (42) to always have a tendency to move along the fixed pin (41) toward the position of the output shaft of the main motor (12).

3. The fan system for a range hood according to claim 2, characterized in that: The elastic element (43) is a tension spring sleeved on the fixed pin (41) and located on the side of the sliding element (42) facing the output shaft of the main motor (12).

4. The fan system for a range hood according to claim 1, characterized in that: The first annular conductive unit (51) includes a first positive annular conductive sheet (511) and a first negative annular conductive sheet (512) arranged radially spaced apart; the second annular conductive unit (52) includes a second positive annular conductive sheet (521) and a second negative annular conductive sheet (522) arranged radially spaced apart; the third annular conductive unit (61) includes a third positive annular conductive sheet (611) and a third negative annular conductive sheet (612) arranged radially spaced apart; and the fourth annular conductive unit (62) includes a first positive annular conductive sheet (511) and a second negative annular conductive sheet (512) arranged radially spaced apart. A fourth positive annular conductive sheet (621) and a fourth negative annular conductive sheet (622) are arranged at intervals. The first positive annular conductive sheet (511) is opposite to the third positive annular conductive sheet (611), the first negative annular conductive sheet (512) is opposite to the third negative annular conductive sheet (612), the second positive annular conductive sheet (521) is opposite to the fourth negative annular conductive sheet (622), and the second negative annular conductive sheet (522) is opposite to the fourth positive annular conductive sheet (621).

5. The fan system for a range hood according to claim 1, characterized in that: The sliding member (42) is an integrally annular sliding sleeve. The outer peripheral wall of the sliding sleeve is provided with a first conductive ring (421) and a second conductive ring (422) spaced apart along the axial direction of the sliding sleeve. The first conductive ring (421) and the second conductive ring (422) together constitute the sliding contact of the sliding member.

6. The fan system for a range hood according to any one of claims 1 to 5, characterized in that: It also includes a power generation device, which includes a generator (31) and an auxiliary fan blade (32) located at the air inlet of the volute (10) and capable of rotating under the influence of the airflow at the air inlet. The auxiliary fan blade (32) is connected to the power input shaft of the generator (31). The switching device is located in the circuit between the generator (31) and the auxiliary motor (21).

7. The fan system for a range hood according to any one of claims 1 to 5, characterized in that: It also includes a bracket assembly (70), on which at least one of the first switch disk (50) and the second switch disk (60) is disposed. The bracket assembly (70) includes a heat-conducting element (74) that can contact the main body of the main motor (12) and a shape memory element (73) that is connected to the heat-conducting element (74) and changes shape when heated. The shape memory element (73) can drive the first switch disk (50) or the second switch disk (60) disposed on the bracket assembly (70) to move closer or further away as its temperature changes, thereby connecting or disconnecting the sliding contact on the sliding member (42) with the fixed contact on the switch disk assembly.

8. The fan system for a range hood according to claim 7, characterized in that: It also includes a support plate (71) fixed relative to the volute (10) and at least two connecting posts (72) connected to the support plate (71) and spaced apart circumferentially along the support plate (71). Each connecting post (72) extends substantially along the axis of the output shaft of the main motor (12). Each connecting post (72) is provided with the aforementioned shape memory element (73). The shape memory element (73) changes the overall length of the connecting post (72) as its heating temperature changes. One of the first switch plate (50) and the second switch plate (60) is fixed relative to the support plate (71), and the other is connected to each of the connecting posts (72).

9. The fan system for a range hood according to claim 8, characterized in that: The shape memory element (73) is an annular pad that is in the overall ring shape. Each of the connecting posts (72) includes a first post (721) and a second post (722). The first post (721) and the second post (722) are respectively connected to two opposite side walls of the annular pad and extend in the same straight line.

10. The fan system for a range hood according to claim 9, characterized in that: The heat-conducting component (74) is a support arm structure that extends from the annular pad toward the main body of the main motor (12) and contacts the main body of the main motor (12).

11. The fan system for a range hood according to claim 8, characterized in that: The second switch disk (60) is connected to the support disk (71) by at least two first support rods (75) arranged circumferentially on the second switch disk (60), and the first switch disk (50) is connected to each of the connecting posts (72).

12. The fan system for a range hood according to claim 6, characterized in that: The volute (10) has two air inlets, namely a main air inlet (101) and a secondary air inlet (102). The main motor (12) is a dual-output shaft motor, which has a first shaft (121) extending toward the main air inlet (101) and a second shaft (122) extending toward the secondary air inlet (102). The auxiliary fan (32), auxiliary motor (21), switching device and power generation device are all located at the secondary air inlet (102) of the volute (10).

13. The fan system for a range hood according to claim 12, characterized in that: It also includes a support plate (71) fixed relative to the volute (10), an auxiliary motor (21) is located on the side wall of the support plate (71) facing the main motor (12) in the middle, the output shaft of the auxiliary motor (21) is connected to the second shaft (122) of the main motor (12), and a generator (31) is located on the side wall of the support plate (71) away from the main motor (12) in the middle.

14. The fan system for a range hood according to claim 13, characterized in that: The secondary air inlet (102) of the volute (10) is also provided with a motor bracket (13) for fixing the main motor (12), and the outer periphery of the support plate (71) is connected to the motor bracket (13).

15. A range hood, comprising a fan system, characterized in that: The fan system is the same as the fan system for a range hood as described in any one of claims 1 to 14.

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