Heat dissipation and dust prevention structure of three-phase motor

Abstract

The invention discloses a heat dissipation dustproof structure of a three-phase motor, and relates to the technical field of motors, the heat dissipation dustproof structure comprises a motor body, a wind scooper and a heat dissipation cover, the wind scooper and the heat dissipation cover are installed on the outer side of the motor body, the wind scooper and the heat dissipation cover are connected through bolts, the heat dissipation dustproof structure further comprises a wind inlet cover and a circulation assembly, the wind inlet cover is fixedly installed on the outer side of the heat dissipation cover, and the circulation assembly is connected with the wind scooper and the heat dissipation cover. The circulation assembly is fixedly installed in the heat dissipation cover. The wind scooper and the heat dissipation cover are installed on the outer side of the motor body, the wind scooper and the heat dissipation cover can wrap the motor body so that heat dissipation airflow can be guided conveniently, the air inlet cover is arranged at one end of the heat dissipation cover, and the filter screen capable of rotating is arranged between the air inlet cover and the heat dissipation cover so that heat dissipation can be conducted conveniently. The filter screen can filter dust in air entering the device, and the rotatable structure facilitates adjustment of the position of the filter screen, so that automatic cleaning of dust on the outer side of the filter screen is facilitated, and the dustproof performance of the device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a heat dissipation and dust prevention structure for a three-phase motor. Background Art

[0002] At present, motors have been widely used in the automation equipment industry. A large amount of heat is generated during the operation of the motor, which causes the heat inside the motor to continue to increase, affecting the motor performance and shortening the motor life. The existing method is usually to install a fan on one side of the motor, which can only accelerate the heat exchange on the outer surface of the motor, and the effect is poor. At the same time, due to the diversity of the motor working environment, some motors work in a dusty environment. The dust will affect the rotation of the fan, thereby affecting the heat dissipation, and will also increase the wear of the motor and reduce the life of the motor. The existing method usually adds a dust cover for dust prevention. When dealing with fine dust, the dust prevention effect is limited and cannot be completely removed.

[0003] For example, a heat dissipation and dust prevention device for a three-phase asynchronous motor with publication number CN114865830B, the dust removal device for the three-phase asynchronous motor comprises: a motor housing and an installation cavity to which one end of the motor housing is fixedly connected, the side wall of the installation cavity is provided with symmetrically arranged through holes, the installation cavity is used to install components for heat dissipation and dust removal in the motor; a power component, the power component comprises a driving shaft, a screw nut, and a fan blade, the driving shaft is provided with a reciprocating thread pattern, the screw nut is threadedly connected to the driving shaft, a plurality of the fan blades are arranged in a ring array on the driving shaft, the power component is used to provide power for motor heat dissipation, and when the strip filter plate rotates on the side wall of the installation cavity, the dust attached to the side wall of the installation cavity can be scraped off to the lower side wall, and the gas discharged through the exhaust pipe can blow the dust to the outside of the installation cavity through the through hole, so as to achieve the dust removal effect on the inside of the installation cavity.

[0004] A high-efficiency dust-proof heat dissipation motor and a dust-proof heat dissipation method thereof with publication number CN115425791A relate to the field of motors. The high-efficiency dust-proof heat dissipation motor comprises a housing, a front end cover is fixedly arranged on one side of the housing, a rear end cover is fixedly arranged on the other side of the housing, a plurality of dust removal and heat dissipation holes are provided inside the front end cover and the rear end cover at one end away from the housing, electrode sheets are fixedly arranged at the upper and lower ends of the inner wall of the dust removal and heat dissipation hole at one side away from the housing, two opposite electrode sheets are respectively connected to the positive and negative poles of the power supply, a plurality of dust collecting grooves are arranged inside the dust removal and heat dissipation hole at one end close to the housing, a fan shaft is rotatably arranged inside the rear end cover, and a fan blade is fixedly sleeved on the outside of the fan shaft. The dust is ionized by a high-voltage electrostatic field, so that it is charged and adsorbed by the electrode sheets, so as to achieve the effect of removing fine dust, and a clean airflow flows through the inside of the motor, so as to achieve the purpose of accelerating the heat exchange inside the motor.

[0005] The above technical solution has some problems in practical application. During the heat dissipation of the motor, dust will still flow into the device with the air, and during the dust cleaning process, the dust moves inside the device and cannot be discharged well. Therefore, it is difficult to ensure the heat dissipation and dust prevention effects of the device.

[0006] Therefore, it is necessary to invent a three-phase motor heat dissipation and dustproof structure to solve the above problems. Summary of the invention

[0007] The object of the present invention is to provide a three-phase motor heat dissipation and dust prevention structure to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions: a three-phase motor heat dissipation and dustproof structure, comprising a motor body and an air guide cover and a heat dissipation cover installed on the outside of the motor body, wherein the air guide cover and the heat dissipation cover are connected by bolts, and further comprising an air inlet cover and a circulation component, wherein the air inlet cover is fixedly installed on the outside of the heat dissipation cover, and the circulation component is fixedly installed on the inside of the heat dissipation cover; A plurality of heat dissipation fins are installed around the outer side wall of the motor body; The heat dissipation cover is set as a hollow structure, and a support frame is fixedly installed at one end of the heat dissipation cover, an end plate is fixedly installed at one end of the support frame, a filter screen with an annular structure is rotatably installed on the outer side of the support frame, a partition is fixedly installed inside the support frame, and a plurality of transmission components for driving the filter screen to rotate are also installed inside the support frame; A plurality of support blocks are installed around the inner side of the air inlet cover, and the support blocks are fixedly installed on the outer side of the heat dissipation cover; The circulation component is used to guide the flow of air. The circulation component includes a fixed cover and an extension cover. The fixed cover is fixedly installed inside the heat dissipation cover, and the extension cover is fixedly installed at one end of the fixed cover.

[0009] Preferably, the circulation component further comprises a connection cover, which is arranged as a semicircular structure and fixedly installed between the fixed cover and the heat dissipation cover, and the top end of the connection cover is flush with the lower surface of the partition.

[0010] Preferably, the air guide assembly includes a transmission shaft, a support seat, a wind wheel and fan guide blades. The transmission shaft is rotatably installed inside a fixed cover, the support seat is rotatably installed on one end of the transmission shaft, and the support seat is fixedly installed inside the fixed cover, and the wind wheel and fan guide blades are horizontally fixedly installed in sequence in the middle of the transmission shaft.

[0011] Preferably, the air guide assembly also includes a connecting sleeve for connecting the transmission shaft and the output shaft of the motor body, the connecting sleeve is fixedly installed on one end of the transmission shaft, and the connecting sleeve is sleeve-mounted on one end of the output shaft of the motor body.

[0012] Preferably, a slip ring of an annular structure is fixedly mounted on the outer side of the filter screen, and the slip ring is slidably mounted on the outer side of the support frame.

[0013] Preferably, the transmission assembly includes a connecting groove, a friction wheel, a connecting shaft and a fan-absorbing fan blade, the connecting groove is opened on the inner wall of the support frame, the friction wheel is rotatably installed inside the connecting groove, and the outer wall of the friction wheel is in contact with the inner wall of the slip ring, the connecting shaft is fixedly installed on the middle part of the friction wheel, the fan-absorbing fan blade is fixedly installed on one end of the connecting shaft, and the fan-absorbing fan blade is installed inside the heat dissipation cover.

[0014] Preferably, the transmission assembly further comprises a support, the support is rotatably mounted on the middle portion of the connecting shaft, and the support is fixedly mounted at the notch of the connecting groove.

[0015] Preferably, the top end of the heat dissipation fin is arranged as an inclined structure, and gaps are arranged between the plurality of heat dissipation fins.

[0016] Preferably, the extension cover is configured as a horn structure, and the end of the extension cover with a smaller opening is sleeved and installed on the outside of the heat dissipation fins, and the other end of the fixed cover is installed with an air guide assembly.

[0017] Preferably, the air inlet cover is configured as a trumpet structure, and the opening of one end of the air inlet cover close to the heat dissipation cover is larger.

[0018] Technical effects and advantages of the present invention: 1. The present invention installs an air guide cover and a heat dissipation cover on the outside of the motor body, and the air guide cover and the heat dissipation cover can wrap the motor body to guide the heat dissipation airflow. An air inlet cover is arranged at one end of the heat dissipation cover, and a rotatable filter is arranged between the air inlet cover and the heat dissipation cover. The filter can filter the dust in the air entering the device, and the rotatable structure facilitates the adjustment of the filter position, thereby facilitating the automatic cleaning of the dust outside the filter, so as to improve the dustproof performance of the device; 2. The present invention arranges a circulation component inside the heat dissipation cover, and the circulation component includes a fixed cover and a connecting cover. The fixed cover and the connecting cover can extract the air passing through the filter screen and transport the air to the outside of the motor body to achieve the heat dissipation effect. In this process, the semicircular structure of the connecting cover can realize the extraction of air on one side of the heat dissipation cover, and ensure that the air is discharged from the other side of the heat dissipation cover after passing through the motor body, thereby controlling the flow direction of the air in the process of air circulation, and can realize the cleaning of dust attached to the filter screen in the process of air discharge, so as to improve the dust prevention effect of the device; 3. The present invention arranges a transmission shaft inside the circulation component, and arranges a wind wheel and fan blades outside the transmission shaft. The annular structure of the wind wheel can draw air in the connection cover, and the fan blades can realize horizontal transportation of the air after being drawn, thereby ensuring that the air can reach the outside of the motor body. By arranging heat dissipation fins on the outside of the motor body, and the top of the heat dissipation fins is arranged as an inclined structure, the design of the inclined structure can increase the contact area and heat exchange efficiency between the air and the heat dissipation fins, thereby achieving the effect of improving the heat dissipation efficiency of the motor body. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 It is a schematic cross-sectional view of the overall structure of the present invention.

[0021] Figure 3 It is a schematic cross-sectional view of the overall structure of the present invention.

[0022] Figure 4 It is a schematic diagram of the heat dissipation cover and the air inlet cover structure of the present invention.

[0023] Figure 5 It is a schematic diagram of the heat dissipation cover structure of the present invention.

[0024] Figure 6 It is a schematic cross-sectional view of the heat dissipation cover structure of the present invention.

[0025] Figure 7 For the present invention Figure 6 A schematic diagram of the enlarged structure in the middle.

[0026] Figure 8 It is a schematic diagram of the structure of the air inlet cover of the present invention.

[0027] Fig. 9 It is a schematic diagram of the structure of the wind wheel and the fan blades of the present invention.

[0028] Fig.10 The figure is a flow trajectory diagram of air inside the heat dissipation cover of the present invention.

[0029] In the figure: 1. motor body; 2. wind guide cover; 3. heat dissipation cover; 4. air inlet cover; 5. circulation component; 11. heat dissipation fin; 31. support frame; 32. end plate; 33. filter; 331. slip ring; 332. connecting groove; 333. friction wheel; 334. connecting shaft; 335. fan blade; 336. support; 34. partition; 41. support block; 51. fixed cover; 52. extension cover; 53. connecting cover; 54. transmission shaft; 55. support seat; 56. wind wheel; 57. fan guide blade; 58. connecting sleeve. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present invention provides Figures 1 to 10 A three-phase motor heat dissipation and dustproof structure shown includes a motor body 1 and an air guide cover 2 and a heat dissipation cover 3 installed on the outside of the motor body 1, the air guide cover 2 and the heat dissipation cover 3 are connected by bolts, and also includes an air inlet cover 4 and a circulation component 5, the air inlet cover 4 is fixedly installed on the outside of the heat dissipation cover 3, and the circulation component 5 is fixedly installed inside the heat dissipation cover 3; A plurality of heat dissipation fins 11 are installed around the outer wall of the motor body 1. The top of the heat dissipation fin 11 is set to an inclined structure. There are gaps between the plurality of heat dissipation fins 11. The design of the inclined structure can increase the contact area and heat exchange efficiency between the air and the heat dissipation fin 11, thereby achieving the effect of improving the heat dissipation efficiency of the motor body 1. The heat dissipation cover 3 is set as a hollow structure, and a support frame 31 is fixedly installed at one end of the heat dissipation cover 3, an end plate 32 is fixedly installed at one end of the support frame 31, a filter screen 33 of an annular structure is rotatably installed on the outer side of the support frame 31, a partition plate 34 is fixedly installed inside the support frame 31, and a plurality of transmission components for driving the filter screen 33 to rotate are also installed inside the support frame 31. The setting of the transmission components enables the filter screen 33 to rotate, so as to change the position of filtering dust on the outer side of the filter screen 33, and to achieve recoil cleaning of the filter screen 33 during air flow; In addition, a slip ring 331 of an annular structure is fixedly installed on the outer side of the filter 33, and the slip ring 331 is slidably installed on the outer side of the support frame 31. The setting of the slip ring 331 facilitates the rotation of the filter 33. The transmission assembly includes a connecting groove 332, a friction wheel 333, a connecting shaft 334 and a fan-receiving blade 335. The connecting groove 332 is provided on the inner side wall of the support frame 31. The friction wheel 333 is rotatably mounted inside the connecting groove 332, and the outer side wall of the friction wheel 333 is fitted with the inner side wall of the slip ring 331. The connecting shaft 334 is fixedly mounted on the middle part of the friction wheel 333. The fan-receiving blade 335 is fixedly mounted on one end of the connecting shaft 334, and the fan-receiving blade 335 is mounted inside the heat dissipation cover 3. The air can push the fan-receiving blade 335 during the circulation process, so that the fan-receiving blade 335 rotates, and the fan-receiving blade 335 can drive the friction wheel 333 to rotate through the connecting shaft 334. The friction wheel 333 can drive the slip ring 331 to rotate through the friction force, and the slip ring 331 can drive the filter 33 to rotate, so that the position of the filter 33 is adjusted. The transmission assembly further includes a support 336, which is rotatably mounted on the middle of the connecting shaft 334, and the support 336 is fixedly mounted on the notch of the connecting groove 332, so that the support 336 can support and fix the connecting shaft 334; In addition, a plurality of support blocks 41 are installed around the inner side of the air inlet cover 4, and the support blocks 41 are fixedly installed on the outer side of the heat dissipation cover 3. The air inlet cover 4 is set as a horn structure, and the opening of the end of the air inlet cover 4 close to the heat dissipation cover 3 is larger. The design of the horn structure ensures the protective effect of the air inlet cover 4 while increasing the air inlet range of the air inlet cover 4. The circulation component 5 is used to guide the flow of air. The circulation component 5 includes a fixed cover 51 and an extension cover 52. The fixed cover 51 is fixedly installed inside the heat dissipation cover 3, and the extension cover 52 is fixedly installed at one end of the fixed cover 51. The extension cover 52 is set as a horn structure, and the end of the extension cover 52 with a smaller opening is sleeved and installed on the outside of the heat dissipation fins 11. The design of the horn structure ensures that the air in the fixed cover 51 can enter between the multiple heat dissipation fins 11 to improve the heat exchange efficiency between the air and the heat dissipation fins 11, thereby achieving the purpose of improving the heat dissipation efficiency of the device. The other end of the fixed cover 51 is installed with an air guide component; The circulation component 5 also includes a connecting cover 53, which is set to a semicircular structure and is fixedly installed between the fixed cover 51 and the heat dissipation cover 3. The top of the connecting cover 53 is flush with the lower surface of the partition 34. The design of the semicircular structure allows the connecting cover 53 to extract the air under the partition 34 and transport the air to the air guide cover 2, so that the air pressure in the air guide cover 2 rises, so that the air that has completed the heat exchange is discharged from above the partition 34, so as to achieve the effect of controlling the air flow direction inside the device; The wind guide assembly includes a transmission shaft 54, a support seat 55, a wind wheel 56 and a fan guide blade 57. The transmission shaft 54 ​​is rotatably mounted inside the fixed cover 51, the support seat 55 is rotatably mounted on one end of the transmission shaft 54, and the support seat 55 is fixedly mounted inside the fixed cover 51. The wind wheel 56 and the fan guide blade 57 are horizontally fixedly mounted in the middle of the transmission shaft 54 ​​in sequence. The wind wheel 56 can extract air from the lower half of the interior of the heat dissipation cover 3 through the connecting cover 53. After being extracted, the air is pushed into the wind guide cover 2 through the horizontal guidance of the fan guide blade 57. The wind wheel 56 cooperates with the fan guide blade 57 to realize air delivery while realizing air extraction, so as to improve the flow efficiency of air inside the device, thereby improving the heat dissipation efficiency of the device. The air guide assembly also includes a connecting sleeve 58 for connecting the transmission shaft 54 ​​and the output shaft of the motor body 1 . The connecting sleeve 58 is fixedly installed on one end of the transmission shaft 54 ​​, and the connecting sleeve 58 is sleeved and installed on one end of the output shaft of the motor body 1 .

[0032] In summary, when the device performs heat dissipation treatment on the motor body 1 of the three-phase motor, the air guide cover 2 and the heat dissipation cover 3 can be spliced ​​and installed on the outside of the motor body 1, and the transmission shaft 54 ​​in the circulation component 5 can be connected to the output shaft of the motor body 1 through the connecting sleeve 58. The transmission shaft 54 ​​can drive the wind wheel 56 and the guide fan blades 57 to rotate under the drive of the motor body 1. In this process, the wind wheel 56 can extract air from the lower half of the inside of the heat dissipation cover 3 through the connecting cover 53. After being extracted, the air is pushed into the air guide cover 2 through the horizontal guidance of the guide fan blades 57. At this time, the air enters between the multiple heat dissipation fins 11 under the guidance of the extension cover 52 and moves along the inner wall of the heat dissipation fins 11. At this time, the air realizes heat exchange with the motor body 1 through the heat dissipation fins 11. The air with heat enters the air guide cover 2 under the guidance of the heat dissipation fins 11, and enters the upper half of the heat dissipation cover 3 under the influence of subsequent air injection, and then is discharged through the upper half of the heat dissipation cover 3. The air passes through the filter 33 in the process of entering and exiting the device. The filter 33 can filter and absorb dust in the air to prevent dust from entering the device. In the process of passing through the filter 33, since the filter 33 is rotatably installed on the outside of the support frame 31, a partition 34 is provided inside the support frame 31, and the partition 34 is connected to the connecting cover 53. In the process of guiding the air, the connecting cover 53 can draw the air under the partition 34, and the air inside the heat dissipation cover 3 can be discharged from the top of the partition 34. Therefore, the air in the filter 33 above the partition 34 moves from the inside to the outside, and the air in the filter 33 below the partition 34 moves from the outside to the inside. Movement, so dust accumulates on the outer surface of the filter 33 below the partition 34, and the air can push the fan-receiving blades 335 during the circulation process, so that the fan-receiving blades 335 rotate, and the fan-receiving blades 335 can drive the friction wheel 333 to rotate through the connecting shaft 334, and the friction wheel 333 can drive the slip ring 331 to rotate through the friction force, and the slip ring 331 can drive the filter 33 to rotate, so that the position of the filter 33 is adjusted, so that the filter 33 rotates outside the partition 34 to switch the direction of air passing through different positions on the filter 33, thereby achieving a recoil cleaning effect on the filter 33, thereby improving the dust removal effect of the device.

[0033] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-phase motor heat dissipation and dust prevention structure, characterized in that: The motor comprises a motor body (1), and an air guide cover (2) and a heat dissipation cover (3) mounted on the outside of the motor body (1), wherein the air guide cover (2) and the heat dissipation cover (3) are connected via bolts, and further comprises an air inlet cover (4) and a circulation assembly (5), wherein the air inlet cover (4) is fixedly mounted on the outside of the heat dissipation cover (3), and the circulation assembly (5) is fixedly mounted on the inside of the heat dissipation cover (3); A plurality of heat dissipation fins (11) are mounted around the outer side wall of the motor body (1); The heat dissipation cover (3) is configured as a hollow structure, and a support frame (31) is fixedly mounted on one end of the heat dissipation cover (3), an end plate (32) is fixedly mounted on one end of the support frame (31), a filter screen (33) of an annular structure is rotatably mounted on the outer side of the support frame (31), a partition plate (34) is fixedly mounted on the inside of the support frame (31), and a plurality of transmission components for driving the filter screen (33) to rotate are also mounted on the inside of the support frame (31); A plurality of support blocks (41) are installed around the inner side of the air inlet cover (4), and the support blocks (41) are fixedly installed on the outer side of the heat dissipation cover (3); The circulation component (5) is used to guide the flow of air, and comprises a fixed cover (51) and an extension cover (52), wherein the fixed cover (51) is fixedly mounted inside the heat dissipation cover (3), and the extension cover (52) is fixedly mounted on one end of the fixed cover (51).

2. A three-phase motor heat dissipation and dust prevention structure according to claim 1, characterized in that: The circulation assembly (5) further comprises a connection cover (53), the connection cover (53) being arranged in a semicircular structure, and the connection cover (53) being fixedly mounted between the fixed cover (51) and the heat dissipation cover (3), and the top end of the connection cover (53) being flush with the lower surface of the partition (34).

3. A three-phase motor heat dissipation and dust prevention structure according to claim 2, characterized in that: The wind guide assembly comprises a transmission shaft (54), a support seat (55), a wind wheel (56) and a fan guide blade (57); the transmission shaft (54) is rotatably mounted inside a fixed cover (51); the support seat (55) is rotatably mounted on one end of the transmission shaft (54), and the support seat (55) is fixedly mounted inside the fixed cover (51); the wind wheel (56) and the fan guide blade (57) are horizontally fixedly mounted in sequence on the middle of the transmission shaft (54).

4. A three-phase motor heat dissipation and dust prevention structure according to claim 3, characterized in that: The air guide assembly further comprises a connecting sleeve (58) for connecting the transmission shaft (54) and the output shaft of the motor body (1); the connecting sleeve (58) is fixedly mounted on one end of the transmission shaft (54), and the connecting sleeve (58) is sleeve-mounted on one end of the output shaft of the motor body (1).

5. The three-phase motor heat dissipation and dust prevention structure according to claim 1 is characterized in that: A slip ring (331) with an annular structure is fixedly mounted on the outer side of the filter screen (33), and the slip ring (331) is slidably mounted on the outer side of the support frame (31).

6. A three-phase motor heat dissipation and dust prevention structure according to claim 5, characterized in that: The transmission assembly comprises a connecting groove (332), a friction wheel (333), a connecting shaft (334), and a fan-receiving blade (335); the connecting groove (332) is formed on the inner side wall of the support frame (31); the friction wheel (333) is rotatably mounted inside the connecting groove (332); the outer side wall of the friction wheel (333) is in contact with the inner side wall of the slip ring (331); the connecting shaft (334) is fixedly mounted on the middle part of the friction wheel (333); the fan-receiving blade (335) is fixedly mounted on one end of the connecting shaft (334); and the fan-receiving blade (335) is mounted inside the heat dissipation cover (3).

7. A three-phase motor heat dissipation and dust prevention structure according to claim 6, characterized in that: The transmission assembly further comprises a support (336), wherein the support (336) is rotatably mounted on the middle portion of the connecting shaft (334), and the support (336) is fixedly mounted on the notch of the connecting groove (332).

8. The three-phase motor heat dissipation and dust prevention structure according to claim 1 is characterized in that: The top end of the heat dissipation fin (11) is arranged as an inclined structure, and gaps are arranged between a plurality of the heat dissipation fins (11).

9. The three-phase motor heat dissipation and dust prevention structure according to claim 1, characterized in that: The extension cover (52) is configured as a horn structure, and the end of the extension cover (52) with a smaller opening is sleeved and installed on the outside of the heat dissipation fin (11), and the other end of the fixed cover (51) is installed with an air guide component.

10. The three-phase motor heat dissipation and dust prevention structure according to claim 1, characterized in that: The air inlet cover (4) is configured as a horn structure, and the opening of one end of the air inlet cover (4) close to the heat dissipation cover (3) is relatively large.

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