A centrifugal fan driven by a permanent magnet motor

Abstract

The present invention discloses a centrifugal fan driven by a permanent magnet motor, which relates to the technical field of centrifugal fans. The centrifugal fan includes a housing and an impeller body. The impeller body is rotatably arranged in the housing through an impeller shaft. A motor body is arranged on the housing. The motor body includes a motor shaft and a sleeve. The motor body is connected with a motor shaft. An inner hole is arranged on the motor shaft. A transmission shaft is arranged in the inner hole through a first elastic member. It further includes a sleeve for connecting with the impeller shaft. A first meshing portion is arranged at the end of the transmission shaft. A second meshing portion is arranged on the inner wall of the sleeve. The transmission shaft has a first position and a second position in the axial direction. At the first position, the transmission shaft drives the sleeve to rotate synchronously through the meshing of the first meshing portion and the second meshing portion. At the second position, the impeller shaft is limited, and the transmission shaft idles relative to the sleeve.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal fans, and specifically to a centrifugal fan driven by a permanent magnet motor. Background Art

[0002] As is well known, a centrifugal fan is a machine that relies on the input mechanical energy to increase the gas pressure and discharge the gas. It is a driven fluid machine. Centrifugal fans are widely used in ventilation, dust removal and cooling of factories, mines, tunnels, cooling towers, vehicles, ships and buildings. The structure of a centrifugal fan includes an impeller, a casing, a coupling, an impeller shaft and a motor. The impeller is the main component for generating wind pressure and transmitting energy; the casing is used to introduce and discharge gas, and at the same time convert part of the kinetic energy of the gas into pressure energy; the coupling is used to connect the motor and the fan to transmit torque; the impeller shaft is installed and fixed with the impeller, and the impeller shaft is connected to the motor through the coupling. The motor is a device that converts electrical energy into mechanical energy, and the motor provides rotational power for the impeller. The working principle of the centrifugal fan is as follows: The impeller is driven by the motor to rotate. The gas enters the blade space axially from the fan, and as the impeller rotates, the gas is affected by the centrifugal force to obtain kinetic energy and is discharged from the periphery of the impeller. These gases flow towards the outlet of the ventilator under the guidance of the casing, and at the same time a negative pressure is formed at the center of the impeller to attract the continuous inflow and replenishment of external air flow, so that the fan can continuously discharge gas.

[0003] For example, in the patent with publication number CN217783822U, publication date November 11, 2022, and title "A Centrifugal Fan Driven by a Permanent Magnet Motor", this patent discloses a centrifugal fan driven by a permanent magnet motor, including a permanent magnet motor, an electric control device, a volute, a wind wheel, and a sealing layer; one end of the permanent magnet motor is connected to the electric control device, and the other end of the permanent magnet motor is connected to one end of the volute; the other end of the volute away from the permanent magnet motor is provided with a first opening; the outer side wall of the volute is provided with a second opening; the wind wheel is installed inside the volute; the sealing layer is arranged at the connection position between the permanent magnet motor and the electric control device; the volute includes a first housing and a second housing, and the first housing and the second housing are detachably installed. The fan of this patent is sealed with a sealing layer at the connection position between the permanent magnet motor and the electric control device to achieve the dust-proof and waterproof effects at the connection position; and the volute is composed of two parts, the first housing and the second housing, which are detachably installed, which is more convenient than the traditional integrated volute.

[0004] The deficiencies in the prior art are as follows. Since the output end of the motor (i.e., the motor shaft) is connected to the impeller shaft to drive the impeller to rotate, after the impeller on the centrifugal fan has been used for a long time, due to reasons such as vibration, aging, deformation, and dust adhesion on the impeller, it is easy to cause an increase in the frictional force between the impeller and the housing, resulting in the phenomenon of the impeller getting stuck during rotation. And if the lubrication of the impeller shaft and the motor shaft is not in place, the impeller may also be deformed. After the impeller is deformed, it will wobble during rotation, making it more likely to get stuck. When the impeller gets stuck, the motor is in a normal working state, which makes the motor prone to overload and even burnout. Summary of the Invention

[0005] The purpose of the present invention is to provide a centrifugal fan driven by a permanent magnet motor to solve the above problems in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A centrifugal fan driven by a permanent magnet motor includes a housing and an impeller body. The impeller body is rotatably arranged in the housing through an impeller shaft. A motor body is provided on the housing. The motor body includes a motor shaft and a sleeve. The motor shaft is connected to the motor body. An inner hole is provided on the motor shaft. A transmission shaft is arranged in the inner hole through a first elastic member. It also includes a sleeve for connecting with the impeller shaft;

[0008] A first engaging portion is provided at the end of the transmission shaft, and a second engaging portion is provided on the inner wall of the sleeve;

[0009] The transmission shaft has a first position and a second position in the axial direction. In the first position, the transmission shaft drives the sleeve to rotate synchronously through the engagement of the first engaging portion and the second engaging portion;

[0010] In the second position, the impeller shaft is limited, and the transmission shaft idles relative to the sleeve.

[0011] In the above, the second engaging portion provided on the inner wall of the sleeve is a protruding second protrusion, and the first protrusion and the second protrusion are engaged with each other.

[0012] In the above, the sleeve is installed at the end of the motor shaft in a rotational fit manner.

[0013] In the above, a plurality of straight grooves are evenly opened on the inner wall of the inner hole along its circumferential direction, and the linear direction of each straight groove is the same as the axial direction of the transmission shaft. A plurality of straight blocks are evenly installed on the outer wall of the transmission shaft along its circumferential direction, and each straight block is installed in each straight groove in a sliding fit manner one by one.

[0014] For the above, a transmission ring is installed on the part of the transmission shaft located inside the sleeve, and the transmission ring is installed in the sleeve in a sliding fit manner. A plurality of the first convex portions are uniformly arranged along the circumferential direction of the transmission ring, and the second convex portions are uniformly arranged along the circumferential direction of the sleeve.

[0015] For the above, a driven ring is installed on the side wall of the sleeve away from the second convex portion in a rotational fit manner, and the side wall of the transmission ring away from the second convex portion and the driven ring are connected by a second elastic member.

[0016] For the above, a plurality of first arc-shaped grooves are uniformly formed on the inner wall of the inner hole along its circumferential direction, and each of the first arc-shaped grooves is correspondingly connected to each of the straight grooves, and each of the first arc-shaped grooves and each of the straight blocks are in sliding fit correspondingly.

[0017] For the above, a plurality of second arc-shaped grooves are uniformly formed on the part of the inner wall of the inner hole between the end of the motor shaft and the straight groove along its circumferential direction. A plurality of clamping grooves are uniformly formed on the outer wall of the transmission shaft along its circumferential direction. An activity plate is installed in each of the clamping grooves in a rotational fit manner, and each of the activity plates is installed in the second arc-shaped groove in a sliding fit manner.

[0018] For the above, the activity plate and the inner wall of the second arc-shaped groove are connected by a third elastic member.

[0019] For the above, the end of the first elastic member connected to the inner hole is installed on the inner wall of the inner hole in a rotational fit manner.

[0020] The beneficial effects of the present invention are as follows: When the centrifugal fan needs to conduct gas transportation, the motor shaft is driven by the motor body to drive the transmission shaft to rotate. The transmission shaft drives the sleeve to rotate through the engagement between the first convex portion and the second convex portion. The sleeve drives the impeller shaft and the impeller body to rotate. When the impeller shaft is limited, the motor shaft will drive the transmission shaft to rotate idly in the sleeve to prevent the impeller shaft from being limited and damaging the motor body. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings.

[0022] Figure 1 It is a three-dimensional structure schematic diagram of the present invention;

[0023] Figure 2 It is a partial three-dimensional structure schematic diagram of an embodiment provided by the present invention;

[0024] Figure 3 is the top view of the present invention; Figure 2

[0025] Figure 4 is the schematic cross-sectional structure view at A-A of the present invention; Figure 3

[0026] Figure 5 is the schematic cross-sectional structure view at B-B of the present invention; Figure 3

[0027] Figure 6 is the schematic cross-sectional structure view at C-C of the present invention; Figure 3

[0028] Figure 7 is the schematic cross-sectional structure view at D-D of the present invention; Figure 3

[0029] Figure 8 is the three-dimensional structure schematic view of the first convex part and the second convex part of the present invention;

[0030] Figure 9 is the schematic cross-sectional structure view of another embodiment of the present invention;

[0031] Figure 10 is the schematic cross-sectional structure view of the arc-shaped rack of the present invention;

[0032] Figure 11 is the three-dimensional structure schematic view of the lifting part and the pushing part of the present invention.

[0033] Explanation of reference numerals:

[0034] Motor body; 111, housing; 2, motor shaft; 3, sleeve; 4, inner hole; 5, first elastic member; 6, transmission shaft; 7, first convex part; 8, second convex part; 9, straight groove; 10, straight block; 11, transmission ring; 12, driven ring; 13, second elastic member; 14, first arc-shaped groove; 15, second arc-shaped groove; 16, card slot; 17, movable plate; 18, third elastic member; 19, card teeth; 20, fourth elastic member; 21, arc-shaped rack; 22, lifting part; 23, pushing part. Detailed implementation manners

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further introduced in detail below in conjunction with the accompanying drawings.

[0036] As Figures 1 to 11 ​​​​​As shown, an embodiment provided by the present invention relates to a centrifugal fan driven by a permanent magnet motor, including a housing 111 and an impeller body. The impeller body is rotatably arranged in the housing through an impeller shaft. A motor body 1 is arranged on the housing. The motor body 1 includes a motor shaft 2 and a sleeve 3. The motor body 1 is connected with the motor shaft 2. An inner hole 4 is arranged on the motor shaft 2. A transmission shaft 6 is arranged in the inner hole 4 through a first elastic member 5. It further includes a sleeve 3 for connecting with the impeller shaft;

[0037] A first engaging portion is arranged at the end of the transmission shaft 6, and a second engaging portion is arranged on the inner wall of the sleeve 3;

[0038] The transmission shaft 6 has a first position and a second position in the axial direction. In the first position, the transmission shaft 6 drives the sleeve 3 to rotate synchronously through the engagement of the first engaging portion and the second engaging portion;

[0039] In the second position, the impeller shaft is limited, and the transmission shaft 6 idles relative to the sleeve 3.

[0040] Specifically, a centrifugal fan is a device for gas transportation. The housing 111 is the outer shell of the centrifugal fan. There is a wind cavity inside the housing 111. An impeller body is rotatably installed in the wind cavity through an impeller shaft. The impeller shaft is connected to a sleeve. When the centrifugal fan is transporting gas, the motor body 1 is started to drive the motor shaft 2 to rotate. The motor shaft 2 drives the transmission shaft 6 to rotate. Since the first engaging portion and the second engaging portion are meshed with each other in an interleaved manner (that is, a part of one first engaging portion is located between two adjacent second engaging portions, that is, there is a first engaging portion arranged between two second engaging portions. When the transmission shaft 6 rotates, it drives the first engaging portion to rotate. Through the mutual meshing between the first engaging portion and the second engaging portion, the first engaging portion presses against the side wall of the second engaging portion to enable the first engaging portion to drive the second engaging portion to rotate, and the second engaging portion drives the sleeve to rotate), and under the pressing action of the first elastic member 5 (the first elastic member 5 is a telescopic member capable of stretching and contracting, preferably a spring rod) on the transmission shaft 6, the first engaging portion and the second engaging portion are mutually pressed and meshed, enabling the transmission shaft 6 to drive the sleeve 3 to rotate. The sleeve 3 is connected to the impeller shaft directly or through a coupling to drive the impeller shaft to rotate, so that the motor body 1 can drive the impeller shaft to rotate stably through the motor shaft 2 and the transmission shaft 6. This is the first position. That is, without the limitation of a strong external force (that is, the impeller shaft is restricted), the motor shaft 2 and the transmission shaft 6 transmit power in sequence through the first engaging portion, the second engaging portion, the sleeve 3, and the impeller shaft to drive the impeller shaft, and the impeller shaft drives the impeller body to rotate. When the impeller body rotates in the wind cavity of the housing 111, gas enters the wind cavity from the air inlet of the housing 111. As the impeller body rotates, the gas obtains kinetic energy under the action of centrifugal force and is discharged from the periphery of the impeller body. These gases flow towards the outlet of the housing 111 under the guidance of the housing 111. At the same time, a negative pressure is formed at the central part of the impeller body to attract the continuous inflow and replenishment of external air currents, so that the fan can continuously discharge gas. The gas transportation by the centrifugal fan is common knowledge in the art and will not be elaborated. When the impeller shaft is restricted (such as when the impeller shaft is rusted, the bearing ring is out-of-round, the impeller is deformed, and the impeller is stuck, which will restrict the impeller shaft), the first engaging portion on the transmission shaft 6 and the second engaging portion in the sleeve 3 rotate idly by rubbing against each other. This is the second position. Due to the certain elasticity of the first elastic member 5, when the first engaging portion and the second engaging portion rotate idly by rubbing against each other, the transmission shaft 6 moves axially in the inner hole 4 of the motor shaft 2, causing the motor shaft 2 to rotate idly in the inner hole 4, thus preventing damage to the motor body 1.

[0041] The deficiencies in the prior art are as follows. Since the output end of the motor (i.e., the motor shaft 2) is connected to the impeller shaft to drive the impeller to rotate, after the impeller on the centrifugal fan has been used for a long time, dust is likely to adhere to the impeller, resulting in an increase in the frictional force between the impeller and the housing, causing the impeller to become stuck when rotating. Moreover, due to the insufficient lubrication of the impeller shaft and the motor shaft, the impeller may be deformed. After the impeller is deformed, the impeller shakes when rotating, making it more likely to become stuck. When the impeller becomes stuck, the motor is in a normal working state, making the motor prone to overload and even burnout.

[0042] The beneficial effects of this embodiment: When the centrifugal fan needs to convey gas, the motor body 1 drives the motor shaft 2 to drive the transmission shaft 6 to rotate. The transmission shaft 6 drives the sleeve 3 to rotate through the engagement between the first convex portion and the second convex portion. The sleeve 3 drives the impeller shaft and the impeller body to rotate. When the impeller shaft is limited, the motor shaft will drive the transmission shaft 6 to rotate idly in the sleeve 3 to prevent the impeller shaft from being limited and damaging the motor body 1.

[0043] Further, the first engagement portion provided at the end of the transmission shaft 6 is a convex first convex portion 7, and the second engagement portion provided on the inner wall of the sleeve 3 is a convex second convex portion 8, and the first convex portion 7 and the second convex portion 8 are engaged with each other. Specifically, the number of the first convex portion 7 and the second convex portion 8 is the same and not less than 6. When the transmission shaft 6 rotates, it drives the first convex portion 7 to rotate. The first convex portion 7 squeezes the side wall of the second convex portion 8 through the mutual engagement with the second convex portion 8 to achieve the first convex portion 7 driving the second convex portion 8 to rotate, and the second convex portion 8 drives the sleeve 3 to rotate.

[0044] Further, the sleeve 3 is installed at the end of the motor shaft 2 in a rotationally mating manner. Specifically, the sleeve 3 is installed at the end of the motor shaft 2 in a rotationally mating manner. When the impeller shaft is limited (i.e., when the sleeve 3 is limited), when the motor shaft 2 drives the transmission shaft 6 to rotate idly in the sleeve 3, the sleeve 3 and the motor shaft 2 will not have axial sliding, improving the installation stability of the sleeve 3.

[0045] Further, a plurality of straight grooves 9 are uniformly formed in the inner wall of the inner hole 4 along its circumferential direction, and the linear direction of each of the straight grooves 9 is the same as the axial direction of the transmission shaft 6. A plurality of straight blocks 10 are uniformly installed on the outer wall of the transmission shaft 6 along its circumferential direction, and each of the straight blocks 10 is installed in each of the straight grooves 9 in a sliding fit manner. Specifically, when the motor body 1 drives the motor shaft 2 to rotate, each of the straight grooves 9 on the inner hole 4 of the motor shaft 2 drives the corresponding straight block 10 to rotate, and the straight block 10 drives the transmission shaft 6 to rotate, so that axial transmission can be carried out between the motor shaft 2 and the transmission shaft 6, and idling between the motor shaft 2 and the transmission shaft 6 will not occur, improving the stability of the motor shaft 2 driving the transmission shaft 6 to rotate.

[0046] Further, a transmission ring 11 is installed on the part of the transmission shaft 6 located inside the sleeve 3, and the transmission ring 11 is installed in the sleeve 3 in a sliding fit manner. The first convex portions 7 are uniformly arranged along the circumferential direction of the transmission ring 11, and the second convex portions 8 are uniformly arranged along the circumferential direction of the sleeve 3, and the first convex portions 7 and the second convex portions 8 are in mutual abutment and staggered meshing. Specifically, when the motor body 1 drives the motor shaft 2 to drive the transmission shaft 6 to rotate, the transmission shaft 6 drives the sleeve 3 to rotate through the mutual abutment and staggered meshing of the first convex portions 7 and the second convex portions 8. The sleeve 3 is directly connected to the impeller shaft through a coupling or the sleeve 3 to drive the impeller shaft to rotate, so that the motor body 1 can drive the impeller shaft to rotate stably through the motor shaft 2 and the transmission shaft 6.

[0047] Further, a driven ring 12 is rotatably mounted on the side wall of the sleeve 3 away from the second protrusion 8. The side wall of the driving ring 11 away from the second protrusion 8 is connected to the driven ring 12 by a second elastic member 13. Specifically, when the impeller shaft is in the limit state and the motor shaft 2 drives the transmission shaft 6 to rotate idly in the sleeve 3, when the first protrusion 7 on the transmission shaft 6 and the second protrusion 8 in the sleeve 3 are in frictional idle rotation, due to the mutual abutment between the end of the first protrusion 7 and the end of the second protrusion 8, the first protrusion 7 drives the driving ring 11 to axially slide towards one end close to the motor body 1 in the axial direction of the motor shaft 2. The driving ring 11 drives the transmission shaft 6 to axially slide towards one end close to the motor body 1, so that the first elastic member 5 and the second elastic member 13 (the second elastic member 13 is a telescopic member capable of stretching and contracting, preferably a spring rod) are in a compressed state (that is, the first protrusion 7 and the second protrusion 8 are in the second position). When the end of the first protrusion 7 is inserted into the space between the two second protrusions 8, under the elastic return action of the first elastic member 5 and the second elastic member 13, the driving ring 11 drives the transmission shaft 6 to axially slide towards the end away from the motor body 1, so that the first protrusion 7 and the second protrusion 8 are in a position of mutually staggered abutting engagement (that is, the initial position of the first protrusion 7 and the second protrusion 8, that is, the first protrusion 7 and the second protrusion 8 are in the first position), so as to realize the idle rotation of the motor shaft 2 driving the transmission shaft 6 in the sleeve 3.

[0048] Further, a plurality of first arc-shaped grooves 14 are evenly formed in the inner wall of the inner hole 4 along its circumferential direction, and each of the first arc-shaped grooves 14 is connected to each of the straight grooves 9 in a one-to-one correspondence, and each of the first arc-shaped grooves 14 and each of the straight blocks 10 are in sliding fit with each other. A plurality of second arc-shaped grooves 15 are evenly formed in the part of the inner wall of the inner hole 4 between the end of the motor shaft 2 and the straight groove 9 along its circumferential direction. A plurality of clamping grooves 16 are evenly formed in the outer wall of the transmission shaft 6 along its circumferential direction. A movable plate 17 is rotatably mounted in each of the clamping grooves 16, and each of the movable plates 17 is slidably mounted in the second arc-shaped groove 15. The movable plate 17 and the inner wall of the second arc-shaped groove 15 are connected by a third elastic member 18. Specifically, in the initial position, the movable plate 17 is slidably mounted in the clamping groove 16 and located in the second arc-shaped groove 15, and the third elastic member 18 (the third elastic member 18 is a telescopic member capable of stretching and contracting, preferably a spring) between the second arc-shaped groove 15 and the movable plate 17 is in a stretched state. Since the straight block 10 is slidably mounted in the straight groove 9, even when the third elastic member 18 is in a stretched state, the straight groove 9 limits the straight block 10, so that the third elastic member 18 only has a pulling tendency on the movable plate 17 and will not drive the transmission shaft 6 to rotate. When the impeller shaft is in a limited state and the motor shaft 2 drives the transmission shaft 6 to rotate idly in the sleeve 3, when the first convex portion 7 on the transmission shaft 6 and the second convex portion 8 in the sleeve 3 are in frictional idle rotation, due to the mutual abutment between the end of the first convex portion 7 and the end of the second convex portion 8, the first convex portion 7 drives the transmission ring 11 to axially slide towards the end close to the motor body 1 in the axial direction of the motor shaft 2. The transmission ring 11 drives the transmission shaft 6 to axially slide towards the end close to the motor body 1, so that the first elastic member 5 and the second elastic member 13 are in a compressed state (that is, the first convex portion 7 and the second convex portion 8 are in the second position). During the axial sliding of the transmission shaft 6, the transmission shaft 6 drives the straight block 10 to axially slide towards the end close to the motor body 1 in the straight groove 9, so that the straight block 10 slides into the first arc-shaped groove 14. At this time, the straight groove 9 has no circumferential rotation (that is, the circumferential direction of the motor shaft 2) limit on the straight block 10 (that is, after the straight block 10 slides into the first arc-shaped groove 14, the straight block 10 slides out of the straight groove 9, so that the transmission shaft 6 can rotate circumferentially). At this time, due to the limitation of the second arc-shaped groove 15 on the movable plate 17, the movable plate 17 slides in the clamping groove 16. Since the third elastic member 18 is in a stretched state, the third elastic member 18 has a tendency to pull the transmission shaft 6 to rotate circumferentially. Since the straight groove 9 does not limit the circumferential rotation of the transmission shaft 6 through the straight block 10, the third elastic member 18 pulls the movable plate 17 to rotate into the second arc-shaped groove 15. At the same time, the movable plate 17 drives the transmission shaft 6 to rotate, and the transmission shaft 6 drives the straight block 10 to rotate in the first arc-shaped groove 14.Since the first elastic member 5 and the second elastic member 13 are in a compressed state at this time, after the straight block 10 rotates into the first arc-shaped groove 14, under the pushing action of the first elastic member 5 and the second elastic member 13, the straight block 10 is stuck in the first arc-shaped groove 14, so that the first convex portion 7 and the second convex portion 8 on the transmission shaft 6 are separated. When the motor shaft 2 drives the transmission shaft 6 to rotate, the first convex portion 7 and the second convex portion 8 will not rub against each other, reducing the damage caused by the rubbing collision between the motor shaft 2 and the transmission shaft 6 at the first convex portion 7 and the second convex portion 8; when the staff finds that the motor body 1 drives the motor shaft 2 and the transmission shaft 6 to rotate idly, the power supply of the motor body 1 is turned off. After repairing the limit problem of the impeller shaft, the transmission shaft 6 is rotated to make the straight block 10 slide out of the first arc-shaped groove 14, and under the rebounding action of the first elastic member 5 and the second elastic member 13, the straight block 10 slides back into the straight groove 9 again. At this time, the third elastic member 18 is still in a stretched state.

[0049] Furthermore, the end of the first elastic member 5 connected to the inner hole 4 is installed on the inner wall of the inner hole 4 in a rotational fit manner. Specifically, when the impeller shaft is in a limited state and the movable plate 17 drives the straight block 10 to rotate in the first arc-shaped groove 14 through the transmission shaft 6, due to the rotational installation method between the first elastic member 5 and the inner hole 4, and the second elastic member 13 is installed in the sleeve 3 in a rotational fit manner through the driven ring 12, when the transmission shaft 6 rotates circumferentially, the first elastic member 5 and the second elastic member 13 will rotate accordingly and will not become an obstacle to the circumferential rotation of the transmission shaft 6 (when the first elastic member 5 and the second elastic member 13 are both fixedly installed, during the circumferential rotation of the transmission shaft 6, due to the certain torsional force of the first elastic member 5 and the second elastic member 13, it may hinder the circumferential rotation of the transmission shaft 6, and even if the transmission shaft 6 drives the straight block 10 to slide into the first arc-shaped groove 14 and is limited, the transmission shaft 6 may also rotate back to the initial position under the rebounding action of the first elastic member 5 and the second elastic member 13).

[0050] Preferably, the arrangement directions of the first arc-shaped groove 14 and the second arc-shaped groove 15 in the inner hole 4 are opposite to the circumferential direction in which the motor body 1 drives the motor shaft 2 to rotate. That is, when the motor body 1 drives the motor shaft 2 and the transmission shaft 6 to rotate clockwise, the arrangement directions of the first arc-shaped groove 14 and the second arc-shaped groove 15 in the inner hole 4 are counterclockwise; when the motor body 1 drives the motor shaft 2 and the transmission shaft 6 to rotate counterclockwise, the arrangement directions of the first arc-shaped groove 14 and the second arc-shaped groove 15 in the inner hole 4 are clockwise. Specifically, when the impeller shaft is in the limit state, since the third elastic member 18 is in a stretched state, when the transmission shaft 6 undergoes axial sliding, the third elastic member 18 drives the transmission shaft 6 to undergo circumferential rotation through the movable plate 17. At this time, when the motor shaft 2 drives the transmission shaft 6 to rotate clockwise, and the arrangement directions of the first arc-shaped groove 14 and the second arc-shaped groove 15 in the inner hole 4 are counterclockwise, the third elastic member 18 drives the transmission shaft 6 to rotate counterclockwise through the movable plate 17. At this time, the rotation directions of the motor shaft 2 and the transmission shaft 6 are opposite, making the straight block 10 easily slide into the first arc-shaped groove 14, so that the straight block 10 can stably axially limit the transmission shaft 6, and vice versa.

[0051] In another embodiment provided by the present invention, the obtained first engaging portion is a locking tooth 19, and the second engaging portion is an arc-shaped rack 21. The end of the transmission shaft 6 is located inside the sleeve 3. A plurality of locking teeth 19 are evenly arranged in the circumferential direction of the end of the transmission shaft 6, that is, the locking teeth 19 on the end of the transmission shaft 6 form an incomplete gear. A plurality of fourth elastic members 20 are evenly arranged on the inner wall of the sleeve 3 along its circumferential direction. An arc-shaped rack 21 is arranged on each of the fourth elastic members 20, and the arc-shaped rack 21 and the locking teeth 19 are engaged and matched with each other. A plurality of lifting members 22 are evenly arranged on the part of the inner wall of the sleeve 3 between the fourth elastic members 20 and the arc-shaped rack 21. A plurality of pushing members 23 are evenly installed on the side wall of the transmission ring 11 close to the locking teeth 19 and on the part between the arc-shaped rack 21 and the transmission ring 11 along its circumferential direction, and the pushing members 23 and the lifting members 22 are used in cooperation with each other. The pushing members 23 and the lifting members 22 are integrally arc-shaped, and the opposite end faces between the pushing members 23 and the lifting members 22 are curved wedge-shaped faces (that is, the end face of the pushing member 23 close to the lifting member 22 and the end face of the lifting member 22 close to the pushing member 23 are inclined curved surfaces). Specifically, when the motor body 1 drives the motor shaft 2 to drive the transmission shaft 6 to rotate, the locking teeth 19 and the arc-shaped rack 21 cooperate with each other, so that the transmission shaft 6 drives the arc-shaped rack 21 to rotate through the locking teeth 19, and the arc-shaped rack 21 drives the sleeve 3 to rotate through the fourth elastic members 20 (the fourth elastic members 20 are telescopic members capable of stretching and contracting, preferably spring rods), and this is the first position; when the impeller shaft is limited, the motor body 1 drives the motor shaft 2 to drive the transmission shaft 6 to rotate. The locking teeth 19 on the transmission shaft 6 rotate in the arc-shaped rack 21. Under the elastic return action of the fourth elastic members 20, the locking teeth 19 on the transmission shaft 6 rotate idly in the sleeve 3, and at the same time, the transmission shaft 6 drives the transmission ring 11 to rotate idly in the sleeve 3. When the pushing members 23 on the transmission ring 11 rotate to abut against the lifting members 22 on the inner wall of the sleeve 3 (since at the initial position, the pushing members 23 on the transmission ring 11 and the lifting members 22 on the inner wall of the sleeve 3 are installed in a staggered manner, that is, the part of the pushing member 23 located between two adjacent lifting members 22 (see Figure 10), at this time, the transmission shaft 6 can also drive the sleeve 3 to rotate through the wedge friction transmission between the pushing member 23 and the jacking member 22, improving the stability of the transmission shaft 6 driving the sleeve 3 to rotate. Since the pushing member 23 and the jacking member 22 are in wedge-shaped surface contact, and the sleeve 3 is installed at the end of the motor shaft 2 in a rotational fit manner, when the pushing member 23 and the jacking member 22 are in contact with each other, the pushing member 23 drives the transmission shaft 6 to axially slide towards one end close to the motor body 1 through the transmission ring 11. At the same time, the transmission shaft 6 drives the straight block 10 to axially slide towards one end close to the motor body 1 in the straight groove 9, so that the straight block 10 slides into the first arc-shaped groove 14. At this time, the straight groove 9 has no limit on the circumferential rotation (that is, the circumferential direction of the motor shaft 2) of the straight block 10 (that is, after the straight block 10 slides into the first arc-shaped groove 14, the straight block 10 slides out of the straight groove 9, enabling the transmission shaft 6 to rotate circumferentially). And at this time, due to the limitation of the second arc-shaped groove 15, the movable plate 17 slides in the clamping groove 16. Since the third elastic member 18 is in a stretched state, the third elastic member 18 has a tendency to pull the transmission shaft 6 to rotate circumferentially through the movable plate 17. And the straight groove 9 does not limit the circumferential rotation of the transmission shaft 6 through the straight block 10, enabling the third elastic member 18 to pull the movable plate 17 to rotate into the second arc-shaped groove 15. At the same time, the movable plate 17 drives the transmission shaft 6 to rotate, and the transmission shaft 6 drives the straight block 10 to rotate in the first arc-shaped groove 14. And since the first elastic member 5 and the second elastic member 13 are in a compressed state at this time, after the straight block 10 rotates into the first arc-shaped groove 14, under the pushing action of the first elastic member 5 and the second elastic member 13, the straight block 10 is stuck in the arc-shaped groove, and the transmission shaft 6 will not rotate circumferentially, enabling the first convex portion 7 and the second convex portion 8 on the transmission shaft 6 to be separated. When the motor shaft 2 drives the transmission shaft 6 to rotate, the first convex portion 7 and the second convex portion 8 will not undergo frictional collision, reducing the damage generated when the motor shaft 2 and the transmission shaft 6 undergo frictional collision at the first convex portion 7 and the second convex portion 8.

[0052] Only some exemplary embodiments of the present invention have been described by way of illustration. Undoubtedly, for those of ordinary skill in the art, without departing from the spirit and scope of the present invention, the described embodiments can be modified in various different ways. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A centrifugal fan driven by a permanent magnet motor, comprising a housing and an impeller body, wherein the impeller body is rotatably arranged in the housing through an impeller shaft, and a motor body is arranged on the housing, characterized in that: The motor body comprises a motor shaft and a sleeve, the motor body is connected to the motor shaft, the motor shaft is provided with an inner hole, a transmission shaft is provided in the inner hole through a first elastic member, and also comprises a sleeve for connecting with the impeller shaft; a first meshing portion is provided at the end of the transmission shaft, and a second meshing portion is provided on the inner wall of the sleeve; the transmission shaft has a first position and a second position in the axial direction, In the first position, the transmission shaft drives the sleeve to rotate synchronously through the engagement of the first engagement portion with the second engagement portion; In the second position, the impeller shaft is limited, and the transmission shaft idles relative to the sleeve; The first meshing portion provided at the end of the transmission shaft is a convex first convex portion, the second meshing portion provided on the inner wall of the sleeve is a convex second convex portion, and the first convex portion and the second convex portion are meshed with each other; A plurality of straight grooves are evenly formed on the inner wall of the inner hole along the circumferential direction thereof, and the linear direction of each straight groove is the same as the axial direction of the transmission shaft; a plurality of straight blocks are evenly installed on the outer wall of the transmission shaft along the circumferential direction thereof, and each straight block is installed in each straight groove in a one-to-one corresponding manner in a sliding fit manner; The transmission ring is installed on the part of the transmission shaft located inside the sleeve, and the transmission ring is installed in the sleeve in a sliding fit manner, and the plurality of first protrusions are evenly arranged along the circumferential direction of the transmission ring, and the second protrusions are evenly arranged along the circumferential direction of the sleeve; A driven ring is mounted on the side wall of the sleeve away from the second protrusion in a rotationally matched manner, and the side wall of the transmission ring away from the second protrusion and the driven ring are connected via a second elastic member; A plurality of first arc surface grooves are evenly formed on the inner wall of the inner hole along the circumferential direction thereof, and each of the first arc surface grooves is connected to each of the straight grooves in a one-to-one correspondence, and each of the first arc surface grooves is slidably matched with each of the straight blocks in a one-to-one correspondence; A portion of the inner wall of the inner hole between the end of the motor shaft and the straight groove is uniformly provided with a plurality of second arc grooves along its circumferential direction, and a plurality of clamping grooves are uniformly provided on the outer wall of the transmission shaft along its circumferential direction, and a movable plate is respectively installed in each of the clamping grooves in a rotationally matched manner, and each of the movable plates is installed in the second arc groove in a slidingly matched manner; The movable plate and the inner wall of the second arc groove are connected via a third elastic member; The setting direction of the first arc surface groove and the second arc surface groove in the inner hole is opposite to the circumferential direction of the motor shaft driven by the motor body to rotate. When the motor body drives the motor shaft and the transmission shaft to rotate clockwise, the setting direction of the first arc surface groove and the second arc surface groove in the inner hole is counterclockwise; when the motor body drives the motor shaft and the transmission shaft to rotate counterclockwise, the setting direction of the first arc surface groove and the second arc surface groove in the inner hole is clockwise.

2. A centrifugal fan driven by a permanent magnet motor according to claim 1, characterized in that: The sleeve is mounted on the end of the motor shaft in a rotationally fitted manner.

3. A centrifugal fan driven by a permanent magnet motor according to claim 1, characterized in that: The end portion of the first elastic member connected to the inner hole is mounted on the inner wall of the inner hole in a rotationally fitted manner.

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