Impeller mounting structure for centrifugal fan, centrifugal fan and range hood

Abstract

The utility model relates to an impeller mounting structure for a centrifugal fan, the centrifugal fan and a range hood, and the impeller mounting structure comprises a motor, an impeller, a connecting piece and a connecting piece, the impeller assembly comprises a wheel disc; a pre-tightening groove and a locking groove which are arranged at an interval in the axial direction are formed in the peripheral wall of the output shaft, the wheel disc comprises a disc body and a boss extending from the disc body to the side away from the motor body, a locking cavity is defined in the boss, and the output shaft of the motor can stretch into the locking cavity; the locking assembly comprises a sliding block which is arranged in the locking cavity in a sliding mode in the radial direction, the sliding block is provided with a pre-tightening step and a locking step, the pre-tightening step can be correspondingly clamped into the pre-tightening groove and disengaged from the pre-tightening groove, the locking step can be correspondingly clamped into the locking groove and disengaged from the locking groove, and the side, away from the locking step, of the pre-tightening step is provided with a pre-tightening inclined face. The axial locking structure has the advantages of being convenient to disassemble and assemble, and capable of effectively eliminating an axial clearance so as to ensure the axial locking firmness between the output shaft of the motor and the impeller.

Description

Technical Field

[0001] The utility model relates to the technical field of centrifugal fans, in particular to an impeller mounting structure for a centrifugal fan, a centrifugal fan and a range hood. Background Art

[0002] A range hood is a kitchen appliance for purifying the kitchen environment. The range hood works based on the principle of fluid dynamics. It sucks and exhausts oil fumes through a centrifugal fan installed inside the range hood, and uses a filter screen to filter out some oil particles. The centrifugal fan includes a volute, an impeller installed in the volute, and a motor that drives the impeller to rotate. When the impeller rotates, a negative pressure suction force is generated at the center of the fan, sucking the oil fumes below the range hood into the fan. After being accelerated by the fan, the oil fumes are collected by the volute and guided out of the room.

[0003] For example, a centrifugal fan disclosed in a Chinese utility model patent with the application number 202220245829.8 includes a volute, an impeller, and a motor. The impeller is arranged inside the volute and is driven by the motor. The impeller includes a front disc, a rear disc, a middle disc, blades, and a wheel disc. The output shaft of the motor passes through the fixed shaft sleeve of the wheel disc and is connected to a locking nut. The end of the output shaft of the motor has a threaded section. Among them, the threaded section of the output shaft of the motor is a double-threaded section. Correspondingly, the locking nut has a matching double-threaded hole. Thus, the locking nut can be locked on the output shaft of the motor by rotating forward and can also be locked on the output shaft of the motor by rotating backward. In order to achieve the quick disassembly and assembly of the impeller, there are also centrifugal fans that change the impeller locking structure from a locking nut to a quick-release snap-type locking device. However, changing from a continuously locked nut to a snap locking will cause more or less axial clearance of the impeller. This clearance is an inevitable clearance in the design principle to avoid failure to lock in place. And due to manufacturing tolerances, it will further affect the size of the clearance. The axial clearance of the impeller will cause a clearance between the motor pin shaft and the wheel disc, resulting in collisions due to inertia during the startup process, thus generating abnormal noises. The situation is relatively mild during low-speed startup, but obvious abnormal noises will be generated during high-speed startup.

[0004] Regarding the axial clearance problem of the above-mentioned quick-release snap-type locking device, the current solutions are as follows. One is to sleeve a soft rubber material on the motor pin shaft to make up for the clearance and achieve axial positioning. However, the soft rubber compensation method also has certain defects. Although the soft rubber can compensate for the clearance and eliminate abnormal noises, under high-speed operating conditions, the soft rubber material will be squeezed and fail in a short time, and in an oil-polluted environment, the soft rubber material is prone to aging and failure. Another solution is to make a bevel step on the locking structure to eliminate the axial clearance. However, the bevel step compensation method uses the clamped step for compensation. The contact area of the clamped step is reduced, resulting in serious wear and easy to come out; secondly, the material of the step is reduced and the strength is lowered; finally, under the reverse push of the axial force of the impeller, the clamped step is easy to come out along the bevel, leading to locking failure and further causing the impeller to fall off.

[0005] Therefore, the existing impeller installation structure for centrifugal fans still needs further improvement. Summary of the Utility Model

[0006] The first technical problem to be solved by the present utility model is to provide an impeller installation structure for a centrifugal fan that is convenient for disassembly and assembly and can effectively eliminate the axial clearance, thereby ensuring the axial locking reliability between the output shaft of the motor and the impeller, in view of the current situation of the prior art.

[0007] The second technical problem to be solved by the present utility model is to provide a centrifugal fan applying the above impeller installation structure, in view of the current situation of the prior art.

[0008] The third technical problem to be solved by the present utility model is to provide a range hood applying the above centrifugal fan, in view of the current situation of the prior art.

[0009] The technical solution adopted by the present utility model to solve the first technical problem is as follows: An impeller installation structure for a centrifugal fan, comprising:

[0010] A motor, including a motor body and an output shaft;

[0011] An impeller assembly, including a wheel disc used to connect with the output shaft of the motor;

[0012] Pre-tightening grooves and locking grooves are arranged at intervals along the axial direction on the outer peripheral wall of the output shaft. The pre-tightening grooves are located on the side far from the motor body relative to the locking grooves. The wheel disc includes a disc body and a convex platform extending from the disc body to the side far from the motor body. A locking chamber is defined inside the convex platform. The output shaft of the motor can pass through the disc body and extend into the locking chamber;

[0013] It further includes a locking assembly arranged in the locking chamber. The locking assembly includes:

[0014] The slider is disposed in the locking chamber and slides radially. The slider is provided with a pre-tightening step that can be correspondingly engaged with and disengaged from the pre-tightening groove, and a locking step that can be correspondingly engaged with and disengaged from the locking groove. On the side of the pre-tightening step away from the locking step, there is a pre-tightening inclined surface that gradually inclines towards the side where the pre-tightening step is located from its root to its end.

[0015] The first elastic member is disposed in the locking chamber and acts on the slider, so that the pre-tightening step and the locking step of the slider always have a tendency to move towards the pre-tightening groove and the locking groove of the output shaft.

[0016] The output shaft of the motor is provided with a locking groove and a pre-tightening groove. The slider is correspondingly provided with a locking step and a pre-tightening step. The cooperation between the locking step and the locking groove realizes the quick locking function, and the cooperation between the pre-tightening groove and the pre-tightening step realizes the axial pre-tightening function. When the locking step is stuck into the locking groove, the pre-tightening step acts, and the axial pre-tightening is realized by compensating the clearance through the inclined surface. This axial locking and limiting method is a pure mechanical structure, which will not cause material damage problems of the soft glue solution. At the same time, due to the double-step separation design, there will be no problem of the impeller axially moving out due to force. On the other hand, the double-step (locking step and pre-tightening step) design on the slider separates the locking and pre-tightening functions, fully ensuring the locking safety. When the impeller is subjected to a large axial impact force and the pre-tightening step is subjected to an oblique force to move the slider outwards, when the impeller moves axially by a distance of a locking clearance, the locking step comes into play, making the impeller unable to move, thereby realizing safety protection. After the large impact force disappears, the pre-tightening step and the pre-tightening groove are pre-tightened again to realize the axial clearance compensation.

[0017] In order to ensure the reliability of the cooperation between the locking step and the locking groove, the side wall of the locking step facing the pre-tightening step is a planar structure whose extending direction is perpendicular to the output shaft of the motor, and the corresponding side wall on the locking groove is also a planar structure whose extending direction is perpendicular to the output shaft of the motor. The above structural design enables sufficient contact area between the locking step and the locking groove for locking, and ensures that the material is relatively thick and has sufficient strength.

[0018] As an improvement, the width of the locking step is greater than the width of the pre-tightening step, and the width of the locking step is greater than the groove width of the pre-tightening groove. The difference between the width of the locking step and the groove width of the pre-tightening groove is denoted as d1, where d1≥0.8m. The above structural design can effectively prevent the locking step from being stuck into the pre-tightening groove during the installation process, that is, it can ensure that the locking step can smoothly pass through the pre-tightening groove and enter the locking groove during the pushing process, obtaining good passability, and at the same time ensuring the strength of the locking step.

[0019] As an improvement, the motor shaft includes a shaft shoulder located between the pre-tightening groove and the locking groove, and the radial dimension of the shaft shoulder is smaller than the radial dimension of the main body of the motor shaft. With the above structural design, the locking step can smoothly transition to the pre-tightening groove. The radial dimension of the shaft shoulder is smaller than that of the main body of the motor shaft (generally at least 0.5 mm smaller), which can prevent the locking step from getting stuck on the end face of the shaft shoulder, resulting in installation jamming problems.

[0020] As a further improvement, the difference between the radial dimension of the shaft shoulder and the radial dimension of the main body of the motor shaft is denoted as d2, where d2 ≥ 0.5 mm.

[0021] As an improvement, the groove width of the locking groove is greater than the width of the locking step. The difference between the groove width of the locking groove and the width of the locking step is denoted as d3, where d3 ≥ 0.5 mm.

[0022] As a further improvement, among the two opposite side walls of the locking groove, the side wall adjacent to the pre-tightening groove is denoted as the first side wall, and the side wall away from the pre-tightening groove is denoted as the second side wall. When the output shaft of the motor is in the installed position, the gap between the locking step and the first side wall is denoted as d4, and the gap between the locking step and the second side wall is denoted as d5, where 0.2 mm ≤ d4 ≤ 0.3 mm and 0.5 mm ≤ d5 ≤ 1 mm. The width of the locking groove is greater than the width of the locking step. When installed in place, a gap of 0.5 - 1 mm is reserved between the locking step and the second side wall, and a gap of 0.2 - 0.3 mm is reserved between the locking step and the first side wall, which can prevent the problem that the locking step cannot be properly engaged. The gap between the locking step and the first side wall affects axial transmission. The gap should be as small as possible, mainly considering the influence of tolerance factors and reserving the corresponding error range to avoid failure to engage. The remaining gap can be compensated by the pre-tightening step. Specifically, the gap between the locking step and the first side wall is smaller than the compensation amount of the pre-tightening step.

[0023] As an improvement, the angle formed by the intersection of the pre-tightening inclined plane and the axis of the output shaft of the motor is denoted as α, where 50° ≤ α ≤ 70°. Generally speaking, the above angle α should neither be too large nor too small. If it is too small, it is not enough to overcome the conventional axial force of the impeller. If it is too large, it will affect the size of the compensation amount. The specific design can balance the force and the compensation amount according to the size of the axial force and the space size, and determine the priority design. The larger the angle, the greater the pre-tightening force and the smaller the compensation amount. If there is enough radial space for the compensation stroke, a large angle can also be designed.

[0024] In order to enable the output shaft of the motor to be smoothly inserted into the locking chamber, the head of the output shaft of the motor is provided with a conical head structure.

[0025] In order to ensure the stability of the slider in the locking chamber, a radially extending limit slide is defined in the locking chamber, and the slider is slidably arranged in the limit slide. The first elastic member can adopt various existing technologies and may include various elastic elements such as compression springs, torsion springs, and spring leaves. However, in order to better cooperate with the slider, the first elastic member is a spring, and the slider has a positioning column on which the end of the spring is mounted.

[0026] In order to facilitate the user to operate to release the locking limit between the impeller wheel and the output shaft of the motor, an unlocking operation component is also included, and the unlocking operation component includes:

[0027] A dial button is rotatably arranged on the slider, and has an operating portion extending from the locking chamber for the user to dial, and a swing wall located in the locking chamber and capable of driving the slider to overcome the elastic force of the first elastic member and move in the opposite direction. The dial button has an unlocking state in which the pre-tightening step and the locking step of the slider are driven to escape from the corresponding pre-tightening groove and the locking groove on the output shaft of the motor as its rotation position changes, and a locking state in which the pre-tightening step and the locking step of the slider are released to allow the pre-tightening step and the locking step of the slider to be inserted into the corresponding pre-tightening groove and the locking groove on the output shaft of the motor;

[0028] The second elastic member acts on the dial button and makes the dial button always have a tendency to deflect from its unlocked state position to its locked state position.

[0029] It is conceivable that the unlocking operation component mentioned above may adopt a push button structure capable of linear movement, and the movement direction of the push button is consistent with the movement direction of the slider.

[0030] As an improvement, the slider has a limit pin whose extension direction is parallel to the axial direction of the output shaft of the motor, and the button is rotatably arranged in the limit pin. The second elastic member is a torsion spring, which is sleeved on the limit pin, and its first end is against the slider, and the other end is against the button.

[0031] In order to facilitate the installation of components such as locking components and unlocking operating components, the boss of the wheel disc includes a boss body and a cover plate. The boss body has a mounting groove that is open at the end. The cover plate is arranged at the open end of the mounting groove of the boss body, thereby defining the locking chamber together with the boss body.

[0032] As an improvement, a limiting rod radially extending on the outer peripheral wall of the output shaft of the motor is further provided. The impeller assembly further includes a middle disc. An opening is formed in the middle of the middle disc. The disc body of the disc has a connecting shaft extending toward one side of the motor body on the other side wall away from the boss. A limiting card slot for the limiting rod to be inserted therein to form circumferential limitation is provided at the end of the connecting shaft. The disc body of the disc is attached and connected to the middle disc, and the connecting shaft passes through the opening of the middle disc and abuts against the limiting rod.

[0033] The technical solution adopted by the present utility model to solve the second technical problem is: a centrifugal fan, including a volute, an impeller assembly and a motor, and the impeller assembly is connected to the output shaft of the motor through the above-mentioned impeller mounting structure for a centrifugal fan.

[0034] The technical solution adopted by the present utility model to solve the third technical problem is: an oil fume extractor, including a fan system, and the fan system adopts the above-mentioned centrifugal fan.

[0035] Compared with the prior art, the advantages of the present utility model are as follows: a locking groove and a pre-tightening groove are provided on the output shaft of the motor, and a locking step and a pre-tightening step are correspondingly provided on the slider. The cooperation between the locking step and the locking groove realizes the quick locking function, and the cooperation between the pre-tightening groove and the pre-tightening step realizes the axial pre-tightening function. When the locking step is stuck into the locking groove, the pre-tightening step acts, and the axial pre-tightening is realized by compensating the clearance through the inclined surface. This axial locking and limiting method is a pure mechanical structure, which will not cause material damage problems of the soft glue solution. At the same time, due to the double-step separation design, the problem that the impeller is axially forced out will not occur. On the other hand, the double-step (locking step and pre-tightening step) design on the slider separates the locking and pre-tightening functions, fully ensuring the locking safety. When the impeller is subjected to a large axial impact force and the pre-tightening step is subjected to an oblique force to move the slider outward, when the impeller moves axially by a locking clearance distance, the locking step takes effect to prevent the impeller from moving, thereby realizing safety protection. After the large impact force disappears, the pre-tightening step and the predicted groove are pre-tightened again to realize the clearance compensation in the axial direction. Description of the Drawings

[0036] Figure 1 is a three-dimensional structural schematic diagram of the impeller mounting structure of the embodiment of the present utility model;

[0037] Figure 2 is an axial sectional view of the impeller mounting structure of the embodiment of the present utility model;

[0038] Figure 3 is a three-dimensional structural schematic diagram of the cooperation between the motor and the disc and other components of the embodiment of the present utility model;

[0039] Figure 4 is Figure 3Schematic three-dimensional structure diagram of the middle cover plate in a separated state;

[0040] Figure 5 Schematic three-dimensional structure diagram of the cooperation between the slider and the unlocking operation component according to an embodiment of the present invention;

[0041] Figure 6 Schematic structure diagram of the slider and the unlocking operation component according to an embodiment of the present invention in a disassembled state;

[0042] Figure 7 Schematic three-dimensional structure diagram of the motor according to an embodiment of the present invention;

[0043] Figure 8 is Figure 2 Enlarged view of part A. Specific embodiments

[0044] The present invention will be further described in detail below with reference to the embodiments in the drawings.

[0045] In the description and claims of the present invention, terms indicating directions such as "front", "rear", "upper", "lower", "left", "right", "side", "top", "bottom", etc. are used to describe various example structural parts and elements of the present invention. However, these terms are used here only for the purpose of convenient explanation and are determined based on the example orientations shown in the drawings. Since the embodiments disclosed by the present invention can be arranged in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to the directions opposite to or consistent with the direction of gravity.

[0046] Figures 1 - 8 Shows a preferred embodiment of the impeller mounting structure for a centrifugal fan, a centrifugal fan, and a range hood of the present invention.

[0047] The impeller mounting structure for a centrifugal fan includes a motor 1, an impeller 20 assembly 2, and a knob 50 unlocking assembly.

[0048] The motor 1 includes a motor 1 body and an output. The end of the output shaft 11 of the motor 1 is provided with a tapered head structure 113, and on the outer peripheral wall at a position adjacent to the tapered head structure 113, there are pre-tightening grooves 111 and locking grooves 112 arranged at intervals along the axial direction. The head of the output shaft 11 of the motor 1 is provided with a tapered head structure 113, which enables the output shaft 11 of the motor 1 to be smoothly inserted into the locking chamber 2420. The pre-tightening grooves 111 and locking grooves 112 on the output shaft 11 of the motor 1 are both annular grooves, and the pre-tightening groove 111 is located on the side away from the motor 1 body relative to the locking groove 112. The part of the output shaft 11 of the motor 1 between the pre-tightening groove 111 and the locking groove 112 is denoted as the shaft shoulder 114, and the radial dimension of this shaft shoulder 114 is smaller than the radial dimension of the main body of the motor 1 shaft. The output shaft 11 of the motor 1 is also provided with a limiting rod 115 extending radially outward at a position away from the end, and the position where the limiting rod 115 is located can be reasonably selected according to the positions of the pre-tightening groove 111, the locking groove 112, and the specific structure of the wheel disc 24 and the locking assembly, so as to ensure reliable axial limitation after the output shaft 11 of the motor 1 and the wheel disc 24 are installed in place.

[0049] The impeller 20 assembly 2 includes an impeller 20 and a wheel disc 24. Specifically, the impeller 20 includes a front disc 21, a rear disc 22, a middle disc 23, and blades arranged circumferentially between the front disc 21 and the rear disc 22 and connected by connectors. The middle disc 23 is located between the front disc 21 and the rear disc 22 and is also connected to each blade. The middle disc 23 extends from the position where each blade is located towards the inside of the impeller 20, and it is in contact with the wheel disc 24 at the middle. An opening 230 is provided at the middle position of the middle disc 23 for the connecting shaft 243 of the wheel disc 24 to pass through.

[0050] The middle disc 23 includes a disc body 241, a convex platform 242 extending from the middle of the disc body 241 towards the side away from the motor 1 body, and a connecting shaft 243 extending from the middle of the disc body 241 towards the side close to the motor 1 body. Since components such as the locking assembly need to be installed in the convex platform 242, the radial dimension of the convex platform 242 is larger than the radial dimension of the connecting shaft 243. The connecting shaft 243 of the wheel disc 24 is designed to be substantially coaxial with the convex platform 242, and its interior is axially hollow, allowing the output shaft 11 of the motor 1 to pass through and extend into the interior of the convex platform 242. The end of the connecting shaft 243 of the wheel disc 24 is provided with limiting card slots 2430 arranged at intervals along the circumferential direction. After the wheel disc 24 is installed in place on the output shaft 11, the disc body 241 of the wheel disc 24 is attached and connected to the middle disc 23, the connecting shaft 243 passes through the opening 230 of the middle disc 23 and abuts against the limiting rod 115, and the limiting rod 115 on the output shaft 11 of the motor 1 is correspondingly clamped into the limiting card slots 2430 of the connecting shaft 243 of the wheel disc 24, forming a circumferential limit between the two. When the output shaft 11 of the motor 1 rotates, it can drive the wheel disc 24 and the middle disc 23 (i.e., the impeller 20) to rotate together.

[0051] A locking chamber 2420 is defined within the boss 242 of the roulette wheel 24. The output shaft 11 of the motor 1 can pass through the connecting shaft 243 and the disc body 241 of the roulette wheel 24 and extend into the locking chamber 2420. A locking assembly for cooperating with the locking groove 112 and the preloading groove 111 of the output shaft 11 of the motor 1 is provided within the locking chamber 2420. The locking assembly includes a slider 3 and a first elastic member 41. Specifically, as Figure 5 and Figure 6 shown, the slider 3 includes a bottom plate 301, two side plates 302 connected to the left and right sides of the bottom plate 301 and arranged oppositely, a rear plate 303 connected between the rear ends of the two side plates 302, and a front plate 304 connected between the front ends of the two side plates 302. Among them, the front plate 304 is designed as an outwardly convex arc-shaped plate structure, and a notch for passing through the dial 50 of the unlocking operation assembly is provided at the top. A through hole 30 for the output shaft 11 of the motor 1 to pass through is provided on the bottom plate 301 of the slider 3. Among them, a locking step 32 for cooperating with the locking groove 112 of the output shaft 11 of the motor 1 is formed at one side edge of the through hole 30. A preloading step 31 extending towards the position where the through hole 30 is located is provided on the rear plate 303 of the slider 3 above the locking step 32. A radially extending limiting slideway 2423 is defined within the locking chamber 2420 of the roulette wheel 24. The side wall of the limiting slideway 2423 for guiding forms a guiding fit with the outer wall surfaces of the two side plates 302 of the slider 3, so as to ensure the stability of the slider 3 moving within the locking chamber 2420. When the slider 3 moves along the limiting slideway 2423, the preloading step 31 on the slider 3 can be correspondingly snapped into and disengaged from the preloading groove 111, and the locking step 32 can be correspondingly snapped into and disengaged from the locking groove 112. The preloading step 31 has a preloading inclined surface 310 that gradually inclines towards the side where the preloading step 31 is located from its root to its end on the side away from the locking step 32. The included angle formed by the intersection of the preloading inclined surface 310 and the axial direction of the output shaft 11 of the motor 1 is denoted as α, where 50° ≤ α ≤ 70°. Generally speaking, the above-mentioned included angle α should not be too large or too small. If it is too small, it is not enough to overcome the axial force of the conventional impeller 20. If it is too large, it will affect the magnitude of the compensation amount. The specific design can balance the force and the compensation amount according to the magnitude of the axial force and the space size, and determine the priority design. The larger the angle, the greater the preloading force and the smaller the compensation amount. If there is enough space in the radial direction for the compensation stroke, a large angle can also be designed. In order to ensure the reliability of the cooperation between the locking step 32 and the locking groove 112, the side wall of the locking step 32 facing the preloading step 31 is a planar structure whose extending direction is perpendicular to the output shaft 11 of the motor 1. Correspondingly, the corresponding side wall on the locking groove 112 is also a planar structure whose extending direction is perpendicular to the output shaft 11 of the motor 1. The above structural design enables the locking step 32 and the locking groove 112 to have sufficient contact area for locking, and ensures that the material is relatively thick and has sufficient strength.

[0052] The first elastic member 41 is disposed within the locking chamber 2420. Specifically, a spring can be used, and this spring abuts between the rear plate 303 of the slider 3 and the inner wall of the locking chamber 2420. A positioning post 33 extending outward is provided on the outer wall of the rear plate 303 of the slider 3, and one end of the spring is correspondingly sleeved on the positioning post 33. Under the elastic force of the above spring, the pre-tightening step 31 and the locking step 32 of the slider 3 always have a tendency to move toward the pre-tightening groove 111 and the locking groove 112 of the output shaft 11.

[0053] In this embodiment, the locking step 32 is a planar step structure with a uniform thickness in the radial direction. The pre-tightening step 31 is a wedge-shaped step structure with a thickness gradually decreasing inward in the radial direction. The shaft shoulder 114 of the motor 1 is also a planar step structure with a uniform thickness in the radial direction. The width of the locking step 32 is greater than the width of the pre-tightening step 31 (at the root), and the width of the locking step 32 is greater than the groove width of the pre-tightening groove 111. Among them, the difference (D4 - D2) between the width of the locking step 32 and the groove width of the pre-tightening groove 111 is denoted as d1, where d1 ≥ 0.8m. The above structural design can effectively prevent the locking step 32 from being stuck in the pre-tightening groove 111 during the installation process, that is, it can ensure that the locking step 32 can smoothly pass through the pre-tightening groove 111 and enter the locking groove 112 during the pushing process, obtaining good passability, and at the same time ensuring the strength of the locking step 32.

[0054] The groove width of the locking groove 112 is greater than the width of the locking step 32. The difference (D1 - D4) between the groove width of the locking groove 112 and the width of the locking step 32 is denoted as d3, where d3 ≥ 0.5mm. Specifically, among the two opposite side walls of the locking groove 112, one side wall adjacent to the pre-tightening groove 111 is denoted as the first side wall 1121, and the side wall far from the pre-tightening groove 111 is denoted as the second side wall 1122. When the output shaft 11 of the motor 1 is in the installed position, the gap between the locking step 32 and the first side wall 1121 is denoted as d4, and the gap between the locking step 32 and the second side wall 1122 is denoted as d5, where 0.2mm ≤ d4 ≤ 0.3mm and 0.5mm ≤ d5 ≤ 1mm. The width of the locking groove 112 is greater than the width of the locking step 32. In the case of the installed position, a gap of 0.5 - 1mm is reserved between the locking step 32 and the second side wall, and a gap of 0.2 - 0.3mm is reserved between the locking step 32 and the first side wall, which can avoid the problem that the locking step 32 cannot be properly engaged. The gap between the locking step 32 and the first side wall affects the axial transmission. The gap should be as small as possible, mainly considering the influence of tolerance factors, leaving a corresponding error range to avoid being unable to be engaged. The remaining gap can be compensated by the pre-tightening step 31. Specifically, the gap between the locking step 32 and the first side wall is less than the compensation amount of the pre-tightening step 31.

[0055] The radial dimension of the shoulder portion 114 of the motor 1 shaft of this embodiment is smaller than the radial dimension of the main body of the motor 1 shaft. Specifically, the difference between the radial dimension of the shoulder portion 114 and the radial dimension of the main body of the motor 1 shaft is recorded as d2, where d2 ≥ 0.5 mm. Since the radial dimension of the shoulder portion 114 of the motor 1 shaft is smaller than the radial dimension of the main body of the motor 1 shaft, this allows the locking step 32 to smoothly transition to the preload groove 111. The radial dimension of the shoulder portion 114 is smaller than the radial dimension of the main body of the motor 1 shaft (generally at least 0.5 mm smaller), which can avoid the locking step 32 being stuck on the end face of the shoulder portion 114, causing installation jamming problems.

[0056] The small circle diameter D3 of the conical head end of the output shaft 11 of the motor 1 should not exceed the locking step 32 in the unlocked state to ensure that the conical head slope can be smoothly touched during installation. The large section of the conical head is designed as a straight section to increase the strength of the preload contact surface and avoid excessive wear and tear that causes a decrease in life. At the same time, the hardness of the material of the output shaft 11 of the motor 1 and the slider 3 should be similar to avoid a significant increase in wear.

[0057] During the initial design, the output shaft 11 of the motor 1 is in a clamped state, and the cooperation between the pre-tightening step 31 and the pre-tightening groove 111 reserves an interference of about 0.2 mm in the lateral direction to compensate for the backward deviation of the pre-tightening step 31 caused by wear or manufacturing errors in the initial stage.

[0058] The unlocking operation assembly includes a dial button 50 and a second elastic member. The bottom plate 301 of the slider 3 is provided with a limit pin 34 whose extension direction is parallel to the axial direction of the output shaft 11 of the motor 1. A mounting hole 53 that can be inserted and matched with the limit pin 34 is correspondingly opened on the main body of the dial button 50. The dial button 50 is rotatably limited in the limit pin 34 through the above-mentioned mounting hole 53. Specifically, the dial button 50 has an operating part 51 that extends from the locking chamber 2420 and is for the user to dial, and a swing wall located in the locking chamber 2420 and can drive the slider 3 to overcome the elastic force of the first elastic member 41 and move in the opposite direction. Figure 4 As shown, a circumferential wall of the boss 242 of the wheel 24 is provided with a paving opening 2424 for the operating portion 51 of the dial button 50 to extend out and rotatably move. The swing arm 52 of the dial button 50 acts on the outer wall surface of the arc-shaped plate at the front of the slider 3, and as the dial button 50 rotates, it can apply pressure to the slider 3 to overcome the elastic force of the first elastic member 41 and move in the reverse direction, so that the pre-tightening step 31 and the locking step 32 of the slider 3 are disengaged from the corresponding pre-tightening groove 111 and the locking groove 112 on the output shaft 11 of the motor 1 and are in an unlocked state.

[0059] The second elastic member is a torsion spring 42. The torsion spring 42 is sleeved on the above-mentioned limit pin 34. Its first end abuts against a vertical plate 3010 on the bottom plate 301 of the slider 3, and the other end abuts against the dial 50, so that the dial 50 always has a tendency to deflect from the position where it is in the unlocked state to the position where it is in the locked state. When the user releases the dial 50, the torsion spring 42 acts on the dial 50 to make it rotate in the reverse direction. In this way, the dial 50 can contact and limit the pressure on the slider 3, allowing the pre-tightening step 31 and the locking step 32 of the slider 3 (under the action of the first elastic member 41) to be engaged with the corresponding pre-tightening groove 111 and locking groove 112 on the output shaft 11 of the motor 1 and be in the locked state.

[0060] The boss 242 of the wheel disc 24 includes a boss body 2421 and a cover plate 2422. The boss body 2421 has a mounting groove with an open end at the end. The cover plate is covered on the open end of the mounting groove of the boss body 2421, so as to define the above-mentioned locking chamber 2420 with the boss body 2421. When it is necessary to install components such as the locking component and the unlocking operation component, the cover plate can be disassembled. After the above components are installed in place, the cover plate is installed again. Specifically, the cover plate can be connected to the open end of the mounting groove by means of snap connection, screw 60 connection, etc. For example, Figure 4 shows the way of connecting the two by screws 60.

[0061] In this embodiment, the output shaft 11 of the motor 1 is provided with a locking groove 112 and a pre-tightening groove 111. The slider 3 is correspondingly provided with a locking step 32 and a pre-tightening step 31. The locking step 32 cooperates with the locking groove 112 to realize the quick locking function, and the pre-tightening groove 111 cooperates with the pre-tightening step 31 to realize the axial pre-tightening function. When the locking step 32 is stuck into the locking groove 112, the pre-tightening step 31 acts, and the axial pre-tightening is realized by compensating the clearance through the inclined surface. This axial locking and limiting method is a pure mechanical structure, which will not cause the problem of material damage of the soft glue solution. At the same time, due to the double-step separation design, there will be no problem that the impeller 20 axially moves out due to force. On the other hand, the double-step (locking step 32 and pre-tightening step 31) design on the slider 3 separates the locking and pre-tightening functions, fully ensuring the locking safety. When the impeller 20 is subjected to a large axial impact force and the pre-tightening step 31 is subjected to an oblique force to move the slider 3 outward, when the impeller 20 moves axially by a locking clearance distance, the locking step 32 comes into play, making the impeller 20 unable to move, thereby realizing safety protection. After the large impact force disappears, the pre-tightening step 31 and the predicted groove are pre-tightened again to realize the axial clearance compensation.

[0062] This embodiment also relates to a centrifugal fan and a range hood. The centrifugal fan includes a volute (not shown), an impeller assembly 2, and a motor 1. The impeller assembly 2 is connected to the output shaft 11 of the motor 1 through the above-mentioned impeller mounting structure for centrifugal fans. The range hood includes a fan system, and the fan system employs the above-mentioned centrifugal fan.

Claims

1. An impeller mounting structure for a centrifugal fan, comprising: A motor (1), including a motor (1) body and an output shaft (11); An impeller assembly (2), including a disk (24) used to connect to the output shaft (11) of the motor (1); It is characterized in that: on the outer peripheral wall of the output shaft (11), pre-tightening grooves (111) and locking grooves (112) are arranged at intervals along the axial direction. The pre-tightening grooves (111) are located on the side away from the motor (1) body relative to the locking grooves (112). The disk (24) includes a disk body (241) and a boss (242) extending from the disk body (241) to the side away from the motor (1) body. A locking chamber (2420) is defined inside the boss (242). The output shaft (11) of the motor (1) can pass through the disk body (241) and extend into the locking chamber (2420); It further includes a locking component arranged inside the locking chamber (2420). The locking component includes: A slider (3), slidably arranged in the radial direction inside the locking chamber (2420). The slider (3) has a pre-tightening step (31) that can be correspondingly inserted into and removed from the pre-tightening groove (111) and a locking step (32) that can be correspondingly inserted into and removed from the locking groove (112). The pre-tightening step (31) has a pre-tightening inclined surface (310) that gradually inclines from its root to its end towards the side where the pre-tightening step (31) is located on the side away from the locking step (32); A first elastic member (41), arranged inside the locking chamber (2420) and acting on the slider (3), so that the pre-tightening step (31) and the locking step (32) of the slider (3) always have a tendency to move towards the pre-tightening groove (111) and the locking groove (112) of the output shaft (11).

2. The impeller mounting structure for a centrifugal fan according to claim 1, wherein: The side wall of the locking step (32) facing the pre-tightening step (31) is a planar structure whose extending direction is perpendicular to the output shaft (11) of the motor (1), and the corresponding side wall on the locking groove (112) is also a planar structure whose extending direction is perpendicular to the output shaft (11) of the motor (1).

3. The impeller mounting structure for a centrifugal fan according to claim 2, wherein: The width of the locking step (32) is greater than the width of the pre-tightening step (31), and the width of the locking step (32) is greater than the groove width of the pre-tightening groove (111). The difference between the width of the locking step (32) and the groove width of the pre-tightening groove (111) is denoted as d1, where d1 ≥ 0.8m.

4. The impeller mounting structure for a centrifugal fan according to claim 3, characterized in that: The motor (1) shaft includes a shaft shoulder (114) located between the pre-tightening groove (111) and the locking groove (112). The radial dimension of the shaft shoulder (114) is smaller than the radial dimension of the main body of the motor (1) shaft.

5. The impeller mounting structure for a centrifugal fan according to claim 4, characterized in that: The difference between the radial dimension of the shaft shoulder (114) and the radial dimension of the main body of the motor (1) shaft is denoted as d2, where d2 ≥ 0.5mm.

6. The impeller mounting structure for a centrifugal fan according to claim 2, wherein: The groove width of the locking groove (112) is greater than the width of the locking step (32). The difference between the groove width of the locking groove (112) and the width of the locking step (32) is denoted as d3, where d3 ≥ 0.5mm.

7. The impeller mounting structure for a centrifugal fan according to claim 6, characterized in that: Of the two side walls opposite to the locking groove (112), one side wall adjacent to the pre-tightening groove (111) is denoted as the first side wall, and one side wall away from the pre-tightening groove (111) is denoted as the second side wall. When the output shaft (11) of the motor (1) is in the installed position, the gap between the locking step (32) and the first side wall is denoted as d4, and the gap between the locking step (32) and the second side wall is denoted as d5, where 0.2 mm ≤ d4 ≤ 0.3 mm and 0.5 mm ≤ d5 ≤ 1 mm.

8. The impeller mounting structure for a centrifugal fan according to claim 1, characterized in that: The angle formed by the intersection of the pre-tightening inclined surface (310) and the axial direction of the output shaft (11) of the motor (1) is denoted as α, where 50° ≤ α ≤ 70°.

9. The impeller mounting structure for a centrifugal fan according to claim 1, wherein: The head of the output shaft (11) of the motor (1) is provided with a tapered head structure (113).

10. The impeller mounting structure for a centrifugal fan according to claim 1, characterized in that: A limiting slideway (2423) extending in the radial direction is defined in the locking chamber (2420). The slider (3) is slidably arranged in the limiting slideway (2423). The first elastic member (41) is a spring. The slider (3) has a positioning post (33) for the end of the spring to be sleeved thereon.

11. The impeller mounting structure for a centrifugal fan according to any one of claims 1 to 10, characterized in that: It further includes an unlocking operation assembly, and this unlocking operation assembly includes: A knob (50) rotatably arranged on the slider (3), which has an operation part (51) for the user to toggle and extending out of the locking chamber (2420) and a swing wall located in the locking chamber (2420) and capable of driving the slider (3) to move reversely against the elastic force of the first elastic member (41). The knob (50) has an unlocking state in which the pre-tightening step (31) and the locking step (32) drive the slider (3) to disengage from the corresponding pre-tightening groove (111) and locking groove (112) on the output shaft (11) of the motor (1), and a locking state in which the pre-tightening step (31) and the locking step (32) of the slider (3) are allowed to be clamped into the corresponding pre-tightening groove (111) and locking groove (112) on the output shaft (11) of the motor (1) by releasing the limit on the slider (3); A second elastic member acting on the knob (50) and making the knob (50) always have a tendency to deflect from the position where it is in the unlocking state to the position where it is in the locking state.

12. The impeller mounting structure for a centrifugal fan according to claim 11, characterized in that: The slider (3) has a limiting pin (34) whose extending direction is parallel to the axial direction of the output shaft (11) of the motor (1). The knob (50) is rotatably arranged in the limiting pin (34). The second elastic member is a torsion spring (42). The torsion spring (42) is sleeved on the limiting pin (34), and its first end abuts against the slider (3), and the other end abuts against the knob (50).

13. The impeller mounting structure for a centrifugal fan according to any one of claims 1 to 10, characterized in that: The boss (242) of the wheel disc (24) includes a boss body (2421) and a cover plate (2422). The boss body (2421) has an installation groove with an open end. The cover plate covers the open end of the installation groove of the boss body (2421), so as to define the locking chamber (2420) with the boss body (2421).

14. The impeller mounting structure for a centrifugal fan according to any one of claims 1 to 10, characterized in that: A limiting rod (115) radially extends on the outer peripheral wall of the output shaft (11) of the motor (1). The impeller assembly (2) further includes a middle disc (23). An opening (230) is formed in the middle of the middle disc (23). On the other side wall of the disc body (241) of the disc (24) away from the boss (242), there is a connecting shaft (243) extending towards the side of the motor (1) body. An end of the connecting shaft (243) has a limiting card slot (2430) for the limiting rod (115) to be inserted therein to form a limit in the circumferential direction. The disc body (241) of the disc (24) is attached and connected to the middle disc (23), and the connecting shaft (243) passes through the opening (230) of the middle disc (23) and abuts against the limiting rod (115).

15. A centrifugal fan, comprising a volute, an impeller assembly (2) and a motor (1), characterized in that: The impeller assembly (2) and the output shaft (11) of the motor (1) are connected by the impeller mounting structure for a centrifugal fan according to any one of claims 1 to 14.

16. An oil fume suction machine, comprising a fan system, characterized in that: The fan system adopts the centrifugal fan according to claim 15.

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