Impeller mounting structure of centrifugal fan, centrifugal fan, and extractor hood

Abstract

The application relates to a centrifugal fan impeller mounting structure, a centrifugal fan and an extractor hood. The centrifugal fan comprises a motor and an impeller assembly. The motor has an output shaft, and the outer peripheral wall of the output shaft is provided with a limiting piece extending radially outward. The impeller assembly comprises an impeller and a wheel disc connected with the impeller. The wheel disc is connected with the output shaft of the motor. The wheel disc has a first side wall facing the main body of the motor and a second side wall facing away from the main body of the motor. The limiting piece can abut against the second side wall of the wheel disc to limit the output shaft in the axial direction. The centrifugal fan impeller mounting structure comprises an axial limiting device with adjustable elastic stiffness. The axial limiting device is arranged on the output shaft of the motor. The axial limiting device has an acting end which is adjustable in the axial direction relative to the position of the wheel disc and can abut against the first side wall of the wheel disc.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, and in particular to an impeller mounting structure for a centrifugal fan, a centrifugal fan, and a range hood. Background Technology

[0002] Centrifugal fans are the core component of range hoods, with the impeller being a key part of the fan system. When oil accumulates on the impeller blades due to grease contamination, the oil alters the blade's streamline and increases its weight. This leads to a decline in the overall performance of the fan system. When the accumulated oil reaches a certain level, the overall performance of the range hood severely deteriorates, noise increases, airflow is significantly reduced, and smoke escape occurs, seriously affecting the user experience. Therefore, after a period of use, users need to perform a major maintenance on the range hood. However, maintenance often requires technical expertise and specialized cleaning services, which are costly. Consequently, the development trend of range hoods is gradually moving towards easier disassembly and assembly. Currently, the impeller is fixed using a left-hand twisted nut, requiring specialized tools for disassembly and assembly. The pre-tightening force is also relatively large, making it difficult to open manually. The numerous rotations also make installation and disassembly inconvenient and unsuitable for frequent operation. Furthermore, insufficient pre-tightening by the user can lead to loosening and safety risks. For example, Chinese utility model patent application CN01239583.8 discloses such a centrifugal fan impeller installation structure. With the promotion of easy-to-disassemble and clean range hoods, the frequency of disassembly and cleaning is gradually increasing, and frequent operation is becoming more inconvenient. Therefore, there is an urgent need to propose an impeller installation structure design for centrifugal fans that is easy to disassemble and assemble. Summary of the Invention

[0003] The first technical problem to be solved by the present invention is to provide an impeller mounting structure for a centrifugal fan that is easy to disassemble and assemble, in light of the current state of the prior art.

[0004] The second technical problem to be solved by the present invention is to provide a centrifugal fan that applies the above-mentioned impeller mounting structure, in view of the current state of the prior art.

[0005] The third technical problem to be solved by the present invention is to provide a range hood that uses the above-mentioned centrifugal fan, in view of the current state of the prior art.

[0006] The technical solution adopted by the present invention to solve the first technical problem mentioned above is as follows: an impeller mounting structure for a centrifugal fan, the centrifugal fan including a motor and an impeller assembly, the motor having an output shaft, the outer peripheral wall of the output shaft having a radially outwardly extending limiting member, the impeller assembly including an impeller and a disc connected to the impeller, the disc being connected to the output shaft of the motor, the disc having a first sidewall facing the main body of the motor and a second sidewall away from the main body of the motor, the limiting member being able to abut against the second sidewall of the disc to limit the output shaft axially;

[0007] Also includes:

[0008] An axial limiting device with adjustable elastic stiffness is provided on the output shaft of the motor. The axial limiting device has an actuating end that is axially adjustable relative to the wheel and can abut against the first sidewall of the wheel.

[0009] To simplify the structure of the axial limiting device, the axial limiting device includes:

[0010] The elastic adjustment device includes a fixed cavity arranged around the output shaft of the motor and used to fill the magnetorheological fluid, a spring disposed in the fixed cavity, and a piston component axially movable on the fixed cavity. The piston component abuts against the first side wall of the wheel, and the spring acts on the piston component, causing the piston component to always have a tendency to move toward the wheel.

[0011] An excitation coil is sleeved around the periphery of the fixed cavity to provide a magnetic field that causes a change in the dynamic viscosity of the magnetorheological fluid in the fixed cavity.

[0012] To ensure the uniformity of the force exerted on the wheel by the elastic adjustment device, the middle part of the fixed cavity is axially connected to form a channel through which the output shaft of the motor passes, and the cross-section of the fixed cavity is also correspondingly annular.

[0013] To ensure the stability of the piston component during axial movement, the piston component includes:

[0014] The pressure relief sleeve is axially movable within the fixed cavity and sleeved outside the output shaft of the motor;

[0015] The piston sleeve is fitted outside the output shaft of the motor. Its first end extends into the fixed cavity and is located radially inside the pressure relief sleeve, and is in sealed contact with the pressure relief sleeve and the fixed cavity. Its second end extends out of the fixed cavity and is used to abut against the first side wall of the wheel.

[0016] In order to install components such as pistons and springs into the fixed cavity, the fixed cavity has an installation opening on the side facing the wheel, and the installation opening is provided with an end cap for restricting the axial movement of the piston.

[0017] In order to fix the excitation coil, a mounting bracket fixed relative to the main body of the motor is also included, and the excitation coil is disposed on the mounting bracket.

[0018] Normally, components such as the fixed cavity can be directly fixed to the output shaft of the motor. However, considering the convenience of installation and maintenance of components such as the fixed cavity, the fixed cavity can be detachably installed on the output shaft of the motor.

[0019] As an improvement, in order to limit the fixed cavity in the axial direction of the motor output shaft, the motor output shaft has a radially outward protruding limiting protrusion, and the side of the fixed cavity away from the wheel abuts against the limiting protrusion.

[0020] In order to effectively improve the stiffness of the elastic adjustment device and ensure the stability of the elastic adjustment device in limiting the wheel in the axial direction, a shim is also included, which is disposed in the fixed cavity and partially located in the gap of the spring.

[0021] When the impeller is about to move axially, the fixed cavity is filled with magnetorheological fluid. Under the action of the magnetic field, the fluid's fluidity decreases, and part of the force is transferred from the spring to the gasket. Since the gasket has a large cross-sectional area, the force required to compress the spring increases, thereby improving the stability of the axial fixation.

[0022] To further improve the reliability of axial fixation, the gasket is arranged in a spiral shape in the gap of the spring.

[0023] To facilitate the installation of the wheel by directly passing through the motor's output shaft and limiting components, the wheel has an axially through hole for the motor's output shaft and limiting components to pass through.

[0024] To further ensure the secure fixation between the wheel and the motor's output shaft and to prevent slippage in the circumferential direction, a limiting groove is provided on the second side wall of the wheel near the perforation to restrict the circumferential rotation of the limiting member.

[0025] The technical solution adopted by the present invention to solve the second technical problem mentioned above is as follows: a centrifugal fan, including a volute, an impeller assembly and a motor, wherein the main body of the motor is connected to the volute, the impeller assembly is disposed inside the volute and connected to the output shaft of the motor, and the output shaft of the motor and the impeller assembly are connected by the above-mentioned centrifugal fan impeller assembly mounting structure.

[0026] The technical solution adopted by the present invention to solve the third technical problem mentioned above is: a range hood, including a fan system, wherein the fan system adopts a centrifugal fan as described above.

[0027] Compared with the prior art, the advantages of this invention are as follows: Since the elastic stiffness of the axial limiting device on the motor's output shaft is adjustable, a relatively small elastic stiffness can be used during initial installation. This facilitates the contact between the active end of the axial limiting device and the impeller, allowing for compression after pressure application and enabling rapid installation of the motor's output shaft and the impeller. After the motor's output shaft and the impeller are in place, a relatively large elastic stiffness can be used, ensuring the reliable axial positioning of the impeller and guaranteeing the impeller's rotational stability. In a preferred embodiment, the axial limiting device uses an adjustment device filled with magnetorheological fluid in conjunction with an excitation coil to adjust its elastic stiffness. Under the influence of an external controllable magnetic field, the impeller can be easily disassembled and assembled, while operating smoothly and with low noise. Attached Figure Description

[0028] Figure 1 This is a three-dimensional structural diagram of the impeller mounting structure of a centrifugal fan according to an embodiment of the present invention;

[0029] Figure 2 This is an axial sectional view of the impeller mounting structure of a centrifugal fan according to an embodiment of the present invention;

[0030] Figure 3 This is an exploded view of the impeller mounting structure of a centrifugal fan according to an embodiment of the present invention;

[0031] Figure 4 This is an exploded view of the impeller mounting structure of a centrifugal fan according to an embodiment of the present invention (impeller assembly omitted);

[0032] Figure 5 This is an axial sectional view of the impeller mounting structure of a centrifugal fan according to an embodiment of the present invention (impeller assembly omitted);

[0033] Figure 6 This is a three-dimensional structural diagram of the wheel according to an embodiment of the present invention. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0035] 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.

[0036] See Figures 1-6 An impeller mounting structure for a centrifugal fan is disclosed, used to fix the impeller assembly 13's disc 14 onto the output shaft 10 of a motor 1, thereby limiting its axial and circumferential movement. The impeller mounting structure includes an axial limiting device with adjustable elastic stiffness, which cooperates with a limiting member 11 and a limiting protrusion 12 on the output shaft 10 of the motor 1 to achieve a secure mounting of the impeller assembly 13 onto the output shaft 10 of the motor 1.

[0037] See Figure 3 and Figure 4 The centrifugal fan includes a motor 1 and an impeller assembly 13. The motor 1 has an output shaft 10, and a radially outwardly extending limiting member 11 is provided on the outer peripheral wall of the end of the output shaft 10. The impeller assembly 13 includes an impeller and a wheel 14 connected to the central disk 131 of the impeller. The wheel 14 is connected to the output shaft 10 of the motor 1. Specifically, the wheel 14 has a first side wall 141 facing the main body of the motor 1 and a second side wall 142 facing away from the main body of the motor 1. The center of the wheel 14 has an axially penetrating through hole 143 for the output shaft 10 of the motor 1 and the limiting member 11 to pass through. A limiting groove 144 for limiting the circumferential rotation of the limiting member 11 is provided on the second side wall 142 of the wheel 14 in the region adjacent to the through hole 143. The shapes of the through hole 143 and the limiting groove 144 on the wheel 14 are basically the same as those of the limiting member 11 on the output shaft 10 of the motor 1. During installation, the end of the output shaft 10 of the motor 1 and the limiting member 11 can pass through the through hole 143 of the wheel 14 and rotate at a certain angle so that the limiting member 11 is housed in the limiting groove 144 of the wheel 14. In this case, the limiting member 11 abuts against the second side wall 142 of the wheel 14 to limit the output shaft 10 in the axial direction, while also achieving the purpose of limiting the output shaft 10 of the motor 1 and the wheel 14 in the circumferential direction.

[0038] An axial limiting device with adjustable elastic stiffness is provided on the output shaft 10 of the motor 1. The axial limiting device has an action end that is axially adjustable relative to the wheel 14 and can abut against the first side wall 141 of the wheel 14.

[0039] Specifically, the axial limiting device includes an elastic adjustment device 2, an excitation coil 3, and a mounting bracket 31. The elastic adjustment device 2 includes a fixed cavity 21, a spring 22, a gasket 23, a piston 24, and an end cap 15. The fixed cavity 21 is filled with magnetorheological fluid and is arranged around the output shaft 10 of the motor 1. Specifically, the middle of the fixed cavity 21 is axially connected to form a mounting channel 210 through which the output shaft 10 of the motor 1 passes. The cross-section of the fixed cavity 21 is also correspondingly annular. More specifically, the fixed cavity 21 includes an inner ring wall and an outer ring wall, and the spring 22 is integrally fitted between the inner ring wall and the outer ring wall. The piston 24 is axially movable within the fixed cavity 21. The outer end of the piston 24 protrudes from the fixed cavity 21 and abuts against the first side wall 141 of the wheel 14, while the inner end is located within the fixed cavity 21 and abuts against the spring 22. Under the elastic action of the spring 22, the piston 24 always tends to move towards the wheel 14. In this embodiment, the outer end of the piston component 24 also constitutes the working end of the axial limiting device.

[0040] See Figure 4 and Figure 5 In this embodiment, the piston component 24 includes a pressure relief sleeve 241 and a piston sleeve 242. The axial dimension of the pressure relief sleeve 241 is smaller than that of the piston sleeve 242. The pressure relief sleeve 241 is axially movable within the fixed cavity 21 and sleeved outside the output shaft 10 of the motor 1, specifically located radially outside the inner annular wall of the fixed cavity 21. The first end of the piston sleeve 242 extends into the fixed cavity 21, specifically located between the inner annular wall of the fixed cavity 21 and the pressure relief sleeve 241, and remains in sealed contact with both during axial sliding. The second end of the piston sleeve 242 extends out of the fixed cavity 21, located radially outside the output shaft 10, and abuts against the first sidewall 141 of the wheel 14.

[0041] In this embodiment, the fixed cavity 21 has an annular mounting opening 211 on the side facing the wheel 14. An end cap 15 is provided at the mounting opening 211 to restrict the axial movement of the piston component 24 (pressure relief sleeve 241). During assembly, components such as the piston component 24 and spring 22 can be inserted into the fixed cavity 21 through the mounting opening 211. Then, after connecting the end cap 15, the piston component 24 is limited.

[0042] In this embodiment, the outer peripheral wall at the root position of the output shaft 10 of the motor 1 has a radially outwardly protruding limiting protrusion 12, wherein the limiting protrusion 12 is a large-diameter section structure with an outer diameter greater than the outer diameter of the main body of the output shaft 10. The fixing cavity 21 is detachably mounted on the output shaft 10 of the motor 1. After the fixing cavity 21 is installed in place, the side of the fixing cavity 21 away from the wheel 14 abuts against the aforementioned limiting protrusion 12. The piston member 24 provided in the fixing cavity 21 has an axial dimension slightly exceeding the end of the output shaft 10. After the wheel 14 is connected, the piston member 24 abuts against the first side wall 141 of the wheel 14.

[0043] The main body of motor 1 is equipped with a mounting bracket 31 at the root of the output shaft 10. This mounting bracket 31 is an annular sleeve fitted outside the fixed cavity 21. The excitation coil 3 is mounted on the mounting bracket 31, which is made of insulating material and does not contact the output shaft 10 of motor 1. When energized, the excitation coil 3 provides a magnetic field that causes a change in the dynamic viscosity of the magnetorheological fluid in the fixed cavity 21. The fixed cavity 21 is filled with magnetorheological fluid, which exhibits low-viscosity Newtonian fluid characteristics when there is no external magnetic field. When an external magnetic field is applied, it exhibits high-viscosity, low-flow Bingham fluid characteristics. There is a corresponding relationship between the viscosity of the liquid and the magnetic flux. Specifically, after the excitation coil 3 is energized, it generates a magnetic field in the axial direction of the motor 1. The magnetorheological fluid, under the applied magnetic field, exhibits a high-viscosity, low-flow Bingham fluid. This allows for control of the viscosity of the liquid by adjusting the magnetic flux. The reduced fluidity of the magnetorheological fluid also helps to fix the impeller 14 axially during operation, resulting in smoother operation. Simultaneously, because the fixing cavity 21 is filled with magnetorheological fluid, and there are gaps in the spring 22, the reduced fluidity of the magnetorheological fluid during operation increases the force required to compress the spring 22, thereby improving the stability of the axial fixation.

[0044] In a further optimized embodiment, to effectively improve the stiffness of the elastic adjustment device 2 and ensure the stability of the elastic adjustment device 2 in limiting the impeller 14 in the axial direction, a gasket 23 is also provided inside the fixed cavity 21. In this embodiment, the gasket 23 is arranged in a spiral shape in the gap of the spring 22. When the impeller is about to move axially, since the fixed cavity 21 is filled with magnetorheological fluid, the fluidity of the magnetorheological fluid decreases under the action of the magnetic field. Part of the force is transmitted from the spring 22 to the gasket 23. Since the cross-sectional area of ​​the gasket 23 is large, the force required to compress the spring 22 increases, thereby further improving the stability of axial fixation.

[0045] The aforementioned method of axial limiting by altering the flowability of the magnetorheological fluid, compared to the existing technology that relies solely on spring 22 (which provides a reverse locking force) for limiting, results in less stable operation but also reduces noise. This is particularly beneficial when applied to range hoods where many fan systems are placed at an angle, thus further reducing noise. Furthermore, due to the properties of the magnetorheological fluid, it also has a certain vibration damping effect, further reducing the noise of the fan system.

[0046] Because the elastic stiffness of the axial limiting device on the output shaft 10 of motor 1 is adjustable, a relatively small elastic stiffness can be used during initial installation. This facilitates the contact between the active end of the axial limiting device and the impeller 14, allowing for compression after pressure application and enabling quick installation of the output shaft 10 of motor 1 and the impeller 14. After the output shaft 10 of motor 1 and the impeller 14 are in place, a relatively large elastic stiffness can be used to ensure the reliable axial positioning of the impeller 14 and the rotational stability of the impeller. In the preferred embodiment, the axial limiting device uses an adjustment device filled with magnetorheological fluid and an excitation coil 3 to adjust its elastic stiffness. Under the action of an external controllable magnetic field, the impeller can be easily disassembled and assembled, while operating smoothly and with low noise. The impeller installation method in this embodiment is more convenient than traditional installation methods and does not require installation tools to ensure the torque of the locking nut.

[0047] This embodiment also relates to a centrifugal fan, including a volute, an impeller assembly 13, and a motor 1. The main body of the motor 1 is connected to the volute, and the impeller assembly 13 is disposed inside the volute. The impeller assembly 13 includes a central disk 131, which is connected to a wheel disk 14. The output shaft 10 of the motor 1 is connected to the wheel disk 14 of the impeller assembly 13 using the aforementioned mounting structure of the centrifugal fan impeller assembly 13.

[0048] This embodiment also relates to a range hood, which includes a body (not shown) and a fan system disposed within the body, wherein the fan system adopts the centrifugal fan described above.

Claims

1. An impeller mounting structure for a centrifugal fan, the centrifugal fan including a motor (1) and an impeller assembly (13), the motor (1) having an output shaft (10) having a radially outwardly extending limiting member (11) on the outer peripheral wall of the output shaft (10), the impeller assembly (13) including an impeller and a disc (14) connected to the impeller, the disc (14) being connected to the output shaft (10) of the motor (1), the disc (14) having a first sidewall (141) facing the body of the motor (1) and a second sidewall (142) away from the body of the motor (1), the limiting member (11) being able to abut against the second sidewall (142) of the disc (14) thereby limiting the output shaft (10) axially; Its features Also includes: An axial limiting device with adjustable elastic stiffness is provided on the output shaft (10) of the motor (1). The axial limiting device has an action end that is axially adjustable relative to the wheel (14) and can abut against the first sidewall (141) of the wheel (14). The axial limiting device includes: The elastic adjustment device (2) includes a fixed cavity (21) arranged around the output shaft (10) of the motor (1) and used to fill the magnetorheological fluid, a spring (22) disposed in the fixed cavity (21), and a piston (24) axially movably disposed on the fixed cavity (21). The piston (24) abuts against the first side wall (141) of the wheel (14). The spring (22) acts on the piston (24) and makes the piston (24) always have a tendency to move toward the wheel (14). An excitation coil (3) is sleeved around the fixed cavity (21) to provide a magnetic field that causes the dynamic viscosity of the magnetorheological fluid in the fixed cavity (21) to change.

2. The impeller mounting structure of the centrifugal fan according to claim 1, characterized in that: The fixed cavity (21) has an axial through-hole in the middle to form an installation channel (210) through which the output shaft (10) of the motor (1) passes, and the cross-section of the fixed cavity (21) is also annular.

3. The impeller mounting structure of the centrifugal fan according to claim 1, characterized in that... The piston (24) includes: The pressure relief sleeve (241) is axially movable in the fixed cavity (21) and sleeved outside the output shaft (10) of the motor (1); The piston sleeve (242) is sleeved outside the output shaft (10) of the motor (1). Its first end extends into the fixed cavity (21) and is located on the radial inner side of the pressure relief sleeve (241), and is in sealed contact with the pressure relief sleeve (241) and the fixed cavity (21). Its second end extends out of the fixed cavity (21) and is used to abut against the first side wall (141) of the wheel (14).

4. The impeller mounting structure of the centrifugal fan according to claim 1, characterized in that: The fixed cavity (21) has a mounting opening (211) on the side facing the wheel (14), and the mounting opening (211) is provided with an end cap (15) for restricting the axial movement of the piston (24).

5. The impeller mounting structure of the centrifugal fan according to claim 1, characterized in that: It also includes a mounting bracket (31) fixed relative to the main body of the motor (1), and the excitation coil (3) is disposed on the mounting bracket (31).

6. The impeller mounting structure of the centrifugal fan according to claim 1, characterized in that: The fixed cavity (21) is detachably mounted on the output shaft (10) of the motor (1).

7. The impeller mounting structure of the centrifugal fan according to claim 6, characterized in that: The output shaft (10) of the motor (1) has a radially outward protruding limiting protrusion (12), and the side of the fixed cavity (21) away from the wheel (14) abuts against the limiting protrusion (12).

8. The impeller mounting structure of the centrifugal fan according to any one of claims 1 to 7, characterized in that: It also includes a gasket (23) disposed within the fixed cavity (21) and partially located in the gap of the spring (22).

9. The impeller mounting structure of the centrifugal fan according to claim 8, characterized in that: The gasket (23) is arranged in a spiral shape in the gap of the spring (22).

10. The impeller mounting structure of the centrifugal fan according to claim 1, characterized in that: The wheel (14) has an axially through hole (143) through which the output shaft (10) of the motor (1) and the limiting member (11) pass.

11. The impeller mounting structure of the centrifugal fan according to claim 10, characterized in that: The second sidewall (142) of the wheel (14) is provided with a limiting groove (144) in the region adjacent to the perforation (143) for limiting the circumferential rotation of the limiting member (11).

12. A centrifugal fan, comprising a volute, an impeller assembly (13), and a motor (1), wherein the main body of the motor (1) is connected to the volute, the impeller assembly (13) is disposed within the volute and connected to the output shaft (10) of the motor (1), characterized in that: The output shaft (10) of the motor (1) is connected to the impeller assembly (13) using the impeller mounting structure of the centrifugal fan as described in any one of claims 1-11.

13. A range hood, comprising a fan system, characterized in that: The fan system uses the centrifugal fan as described in claim 12.

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