CN206831591U - Micro-wave oven - Google Patents

Abstract

The utility model discloses a microwave oven. The microwave oven comprises: an inner cavity, a turntable motor is installed on the bottom surface of the inner cavity and a magnetron is installed on the side; An upper cavity located above the inner cavity and a side cavity located on the side of the inner cavity are defined; a base, the base is arranged below the inner cavity, and a lower cavity located below the inner cavity is defined between the base and the inner cavity; the fan assembly, the fan assembly is set In the side cavity and suitable for blowing air to the magnetron and the turntable motor, wherein at least a part of the magnetron is located in the side cavity, at least a part of the turntable motor is located in the lower cavity, the side cavity is spaced from the upper cavity, and the side cavity is spaced apart from the upper cavity. The cavity communicates with the lower cavity. The microwave oven can effectively improve the heat dissipation performance and use performance of the microwave oven, and at the same time solve the problem of high noise in the existing microwave oven, and the noise reduction effect can reach 6 decibels without increasing the cost.

Description

Micro-wave oven

technical field

The utility model belongs to the field of household appliances, in particular, the utility model relates to a microwave oven.

Background technique

In a microwave oven with a turntable, the turntable motor, magnetron, and transformer are the key working parts of the microwave oven. However, the magnetron and transformer generate great heat when they work, and the temperature of the turntable motor will also rise a lot, requiring fans to For heat dissipation, the heat dissipation problem is related to the safety of microwave oven products. Microwave oven products need to have a smooth heat dissipation air duct for heat dissipation, so as to ensure the heat dissipation effect of microwave ovens.

The heat-generating components in the microwave oven are generally arranged in the microwave oven appliance area located at the bottom of the inner cavity of the shell, so the heat dissipation system usually includes an air inlet arranged at the rear of the shell and a fan driven by an AC shaded pole asynchronous motor. After the ambient wind is sucked into the microwave oven electrical area, it is directly blown to the heat-generating components (such as frequency converter or high-voltage frequency converter and magnetron), and then the hot air is discharged from the air outlet on the side, bottom or top of the microwave oven shell, or the hot air is passed through The air guide hood guides the air into the cavity of the microwave oven. Due to the dispersiveness of the fan blowing, only part of the wind is sent to the heating device, and a lot of part of the wind flows away from the upper cavity of the microwave oven, which does not serve the purpose of heat dissipation. Unnecessary energy consumption is caused; the temperature of the turntable motor rises a lot when it is working, and sufficient air volume is needed to dissipate heat, but the existing air duct system cannot maximize the air flow to the heating element (turntable motor), which affects the performance of the turntable motor. safety and longevity.

Therefore, the technology of existing microwave oven needs further improvement.

Utility model content

The utility model aims to solve one of the technical problems in the related art at least to a certain extent. Therefore, an object of the present utility model is to provide a microwave oven. The microwave oven can effectively improve the heat dissipation performance and use performance of the microwave oven, and at the same time solve the problem of high noise in the existing microwave oven, and the noise reduction effect can reach 6 decibels without increasing the cost.

In one aspect of the utility model, the utility model provides a microwave oven. According to an embodiment of the utility model, the microwave oven includes:

An inner cavity, the bottom surface of the inner cavity is equipped with a turntable motor and a magnetron is installed on the side;

an outer shell, the outer shell is covered on the inner cavity, and an upper cavity above the inner cavity and a side cavity on the side of the inner cavity are defined between the outer shell and the inner cavity;

a base, the base is arranged below the inner cavity, and a lower cavity below the inner cavity is defined between the base and the inner cavity;

a fan assembly, the fan assembly is arranged in the side cavity and is suitable for blowing air to the magnetron and the turntable motor,

Wherein, at least a part of the magnetron is located in the side chamber, at least a part of the turntable motor is located in the lower chamber, the side chamber is separated from the upper chamber, and the side chamber is separated from the upper chamber. The lower cavity is connected.

According to the microwave oven of the embodiment of the utility model, by installing the turntable motor on the bottom surface of the inner cavity and installing the magnetron on the side, it is beneficial for the microwave oven to heat the food in the inner cavity with microwaves, so as to realize the microwave heating function of the microwave oven. The outer shell covers the inner cavity, which is beneficial to protect the components in the microwave oven. At least a part of the magnetron is located in the side cavity, which helps to increase the overall heating performance of the microwave oven, so that the food in the microwave oven is heated more quickly and evenly. The fan assembly is arranged in the side chamber and is suitable for supplying air to the magnetron and the turntable motor, which is beneficial to the heat dissipation of the magnetron and the turntable motor. In addition, the side chamber is separated from the upper chamber, which is beneficial to redistribute the air volume, so that the wind of the fan assembly Concentrating on the side cavity and the lower cavity is beneficial to the heat dissipation of the turntable motor, which can further increase the heat dissipation performance of the microwave oven.

In addition, the microwave oven according to the above-mentioned embodiments of the present utility model may also have the following additional technical features:

In some embodiments of the present utility model, an air inlet opposite to the fan assembly is formed on the outer casing, and an air outlet is formed on the base. Therefore, it is beneficial to improve the heat dissipation performance of the microwave oven.

In some embodiments of the present utility model, a sponge is provided on the upper part of the inner cavity, and the sponge is spaced apart from the side cavity and the upper cavity. Thus, the heat dissipation performance of the microwave oven can be further improved.

In some embodiments of the present utility model, the fan assembly includes: a fan bracket; a ring-shaped wind guide ring, the air inlet end of the wind guide ring is connected with the fan bracket; a fan, the fan is rotatable installed on the fan bracket, and the wind guide ring is arranged around the fan, the air outlet end of the fan protrudes from the air outlet end of the air guide ring, and the end surface of the air outlet end of the fan is in line with the The ratio of the distance L between the end face of the air outlet end of the wind guide ring to the axial width A of the fan is in the range of 23% to 27%; the motor is installed on the fan bracket and connected to the fan connected to drive the fan to rotate. Thereby, the noise of the fan can be reduced under the condition that the air volume is kept constant.

In some embodiments of the present utility model, the blade ends of the fan are spaced apart from the inner peripheral surface of the wind guiding ring by a predetermined distance, and the distance between the blade ends of the fan and the inner peripheral surface of the wind guiding ring The ratio of the gap H to the diameter B of the circumference of the blade tip of the fan is in the range of 3% to 5%. Thus, the noise of the fan can be further reduced.

In some embodiments of the present utility model, the air inlet end of the air guide ring is formed with an outward rounded corner, and the fillet radius R of the air inlet end of the air guide ring is equal to the distance between the circumference of the fan blade end. The ratio of diameter B is in the range of 7% to 10%. Thus, the noise of the fan can be further reduced.

In some embodiments of the present utility model, the distance L between the end surface of the air outlet end of the fan and the end surface of the air outlet end of the wind guide ring is 7 millimeters, the axial width A of the fan is 28 millimeters, and the fan The gap H between the blade end of the fan and the inner peripheral surface of the air guiding ring is 4.5 mm, the diameter B of the circumference where the blade end of the fan is located is 118 mm, and the fillet radius R of the air inlet end of the air guiding ring is is 11mm. Thus, the noise of the fan can be further reduced.

In some embodiments of the present utility model, the fan includes: a hub, the hub is in the shape of a column coaxial with the wind guide ring; blades, the blades are formed on the outer peripheral surface of the hub, the The blades include a plurality of blades arranged at intervals in a direction around the hub. Therefore, it is beneficial to maintain the stability of the airflow.

In some embodiments of the present utility model, the blades include five, and the five blades are equidistantly arranged in a direction around the hub. Therefore, the circulation efficiency of the airflow can be improved, and a reasonable distribution of the airflow circulation efficiency and cost can be realized.

In some embodiments of the present utility model, the fan bracket includes: a skeleton, the skeleton is provided with through holes; a bracket, the bracket is connected with the skeleton, and the bracket has at least one positioning column for motor installation; Wherein, the periphery of the air inlet end of the air guide ring is connected to the periphery of the through hole, the fan is rotatably connected to the bracket, and the fan and the motor are located on the bracket along the guide. Opposite sides in the axial direction of the wind circle. Thus, it is beneficial to form a stable fan assembly and improve the heat dissipation performance of the fan assembly.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

FIG. 1 is a schematic structural view of a fan assembly for a microwave oven according to an embodiment of the present invention;

Fig. 2 is a front view of a fan assembly for a microwave oven according to another embodiment of the present invention;

Fig. 3 is a side view of a fan assembly for a microwave oven according to yet another embodiment of the present invention;

Fig. 4 is a fan front view and a side view of a fan assembly for a microwave oven according to another embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a microwave oven according to yet another embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a microwave oven according to yet another embodiment of the present invention;

Fig. 7 is a schematic structural diagram of a microwave oven according to another embodiment of the present invention.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial ", "radial", "circumferential" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, which are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying No device or element must have a specific orientation, be constructed and operate in a specific orientation, and thus should not be construed as limiting the invention.

In this utility model, unless otherwise specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrated; may be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediary, and may be an internal communication between two elements or an interactive relationship between two elements, unless otherwise stated Clearly defined. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present utility model according to specific situations.

In the present invention, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first feature and the second feature through an intermediary indirect contact. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In one aspect of the utility model, the utility model provides a fan assembly for a microwave oven. According to an embodiment of the present invention, referring to FIGS. 1-4 , the fan assembly includes: a fan bracket 100 , an annular air guiding ring 200 , a fan 300 and a motor 400 .

The fan bracket 100 is used to fix the ring-shaped wind guiding ring 200 , the fan 300 and the motor 400 . The air guide ring, the fan and the motor are fixed at fixed positions on the fan bracket to ensure the stable operation of the entire fan assembly.

The air inlet end of the air guiding ring 200 is connected with the fan bracket 100 . Preferably, the air inlet end of the air guide ring is fixed on the fan bracket, which is beneficial to achieve air guide through the air guide ring.

The fan 300 is rotatably mounted on the fan bracket 100, and the wind guide ring 200 is arranged around the fan 300, the air outlet end of the fan 300 protrudes from the air outlet end of the air guide ring, and the end surface of the air outlet end of the fan is aligned with the wind guide ring. The ratio of the distance L between the end faces of the air outlet to the axial width A of the fan is in the range of 23% to 27%. That is to say, the distance L between the end surface of the air outlet end of the fan and the end surface of the air outlet end of the air guide ring accounts for 23%-27% of the axial width A of the fan, within this range, the noise of the fan can be significantly reduced.

The motor 400 is installed on the fan bracket 100 and connected with the fan 300 to drive the fan 300 to rotate. The motor is fixed on the fan bracket, and the motor drives the fan to rotate. The fan can also be fixed on the fan bracket and connected with the motor 400 . In addition, the fan 300 and the motor 400 are convenient for the motor 400 to drive the fan 300 to rotate. The fan 300 may be directly and rotatably connected to the fan bracket 100 , or the fan 300 may not be directly connected to the fan bracket 100 .

A fan assembly for a microwave oven according to an embodiment of the present invention includes a fan bracket, an air guiding ring, a fan and a motor, the fan bracket is used to fix the air guiding ring, the fan and the motor, the motor provides electric energy for the fan to drive the fan to rotate, and keeps the fan The air volume is constant, the air guide ring plays a role in guiding the fan, and the ratio of the distance L between the end face of the air outlet end of the fan and the end face of the air guide ring to the axial width A of the fan is between 23% and 27% % range can significantly reduce fan noise.

During the use of the fan assembly of the present application, through testing, the noise reduction effect of the fan assembly reaches 6 decibels or higher, and the fan assembly of the present application does not increase the cost, and at the same time can maintain the heat dissipation performance of the microwave oven and improve the microwave oven. cooling efficiency.

Optionally, the blade end of the fan (that is, the free end of the blade of the fan) is spaced a predetermined distance from the inner peripheral surface of the air guide ring, and the gap H between the blade end of the fan and the inner peripheral surface of the air guide ring is the same as that of the fan. The ratio of the diameter B of the circumference where the tip of the blade is located is in the range of 3% to 5%. Therefore, by reasonably setting the proportional relationship between H and B, the circulation efficiency of the airflow can be improved, and the noise of the fan can be further reduced.

Preferably, the air inlet end of the air guide ring is formed with an outward rounded corner, and the ratio of the fillet radius R of the air inlet end of the air guide ring to the diameter B of the circumference of the fan blade end is in the range of 7% to 10%. . There is an outward rounded corner at the air inlet end of the air guide ring, on the one hand, it is conducive to the fixed installation of the air guide ring on the fan bracket, on the other hand, it is beneficial to guide the fan, so that the resistance of the wind at the air inlet end smaller. Setting the ratio of the fillet radius R of the air inlet end of the air guide ring to the diameter B of the circumference of the fan blade end within the range of 7% to 10% is also beneficial to the air guide function of the air guide ring and is conducive to reducing the fan temperature. noise.

In addition, at least a part of the air inlet end of the air guide ring and the fan bracket may be integrally formed, and the rounded corners are formed at the joint between the air guide ring and the fan bracket.

Of course, the air guide ring can also be detachably connected to the fan bracket.

Further preferably, in a specific embodiment of the present utility model, the distance L between the end surface of the air outlet end of the fan and the end surface of the air outlet end of the wind guide ring is 7 millimeters, the axial width A of the fan is 28 millimeters, and the blade end of the fan The gap H between the inner peripheral surface of the air guide ring is 4.5 mm, the diameter B of the circumference where the blade end of the fan is located is 118 mm, and the fillet radius R of the air inlet end of the air guide ring is 11 mm. Thus, the ratio of the distance L between the end surface of the air outlet end of the fan and the end surface of the air outlet end of the wind guide ring to the axial width A of the fan is 25%, in the range of 23% to 27%; The ratio of the gap H between the inner peripheral surfaces of the ring to the diameter B of the circumference where the blade end of the fan is located is 3.8%, in the range of 3% to 5%; The ratio of the diameter B of the circumference on which the ends are located is 9.3%, in the range of 7% to 10%.

As shown in FIG. 2 and in conjunction with FIG. 4 , in some embodiments of the present invention, the fan 300 includes: a hub 31 and blades 32 . The hub 31 is preferably in the shape of a column coaxial with the wind guide ring 200 . The paddles 32 are formed on the outer peripheral surface of the hub 31. The paddles 32 include a plurality of paddles arranged at intervals in the direction around the hub 31. Driven by the multiple paddles 32, the airflow can flow quickly and stably, and the wind guide ring 200 It plays the role of flow collection and diversion, improves the stability of airflow, and reduces noise.

Preferably, the paddles 32 include five, and the five paddles 32 are equidistantly arranged in a direction around the hub 31 . The stability of the air flow is improved, and a reasonable amount of the slurry 32 not only enables the air flow to flow stably, but also improves the flow efficiency of the air flow, and realizes a reasonable distribution of air flow efficiency and cost.

Of course, the present application does not limit the number of paddles 32, and the number of paddles 32 may also be three, six, and so on.

Further, the fan bracket 100 includes: a skeleton 11 and a bracket 12 . The skeleton 11 is provided with a through hole 111 ; the bracket 12 is connected with the skeleton 11 , and the bracket 12 has at least one positioning column 121 for motor installation. Wherein, the periphery of the air inlet end of the air guide ring 200 is connected with the periphery of the through hole 111 , and the fan 300 is rotatably connected with the bracket 12 . The motor and the fan are fixed by the bracket of the fan bracket, and the air guide ring is fixed by the frame, so as to form a stable fan assembly. The frame 11 can be used to fix the motor and the fan, improve the stability of the fan and the motor and facilitate assembly and disassembly, and the frame 11 can serve the purpose of orienting the airflow and improve the heat dissipation performance of the fan assembly.

Optionally, the fan and the motor are located on opposite sides of the bracket along the axis of the wind guide ring. The reasonable arrangement of the fan and the motor improves the stability of the fan assembly, and the fan can also dissipate heat from the motor during the process of driving the air flow, which can improve the heat dissipation efficiency of household appliances such as microwave ovens using the fan assembly.

In addition, the utility model also discloses a microwave oven. The microwave oven can adopt the aforementioned fan assembly for a microwave oven. According to an embodiment of the utility model, referring to FIGS. 5-6 , the microwave oven includes: an inner cavity 500, an outer casing 600, base 700 and fan assembly 800.

A magnetron 51 is installed on the inner cavity 500, and the magnetron 51 can generate microwaves to heat the food in the microwave oven, which is beneficial to the microwave heating of the food in the inner cavity by the microwave oven, and realizes the microwave heating function of the microwave oven. The outer casing 600 covers the inner chamber 500 . The base 700 is arranged under the inner cavity 500 , and a transformer 71 is mounted on the base 700 . The fan assembly 800 is installed on the outer casing 600, and the fan assembly 800 is suitable for blowing air to the magnetron 51 and the transformer 71. The fan assembly 800 may be the fan assembly for a microwave oven in the foregoing embodiments.

According to the microwave oven of the embodiment of the present invention, by adopting the above-mentioned fan assembly for a microwave oven, the noise of the fan can be significantly reduced, that is, the noise of the entire microwave oven can be reduced without increasing the production cost of the microwave oven. Air supply with the transformer is beneficial to maintain the heat dissipation performance of the whole microwave oven and improve the efficiency of the microwave oven.

During the use of the fan assembly of the present application, it is detected that the noise reduction effect of the fan assembly reaches 6 decibels or higher. Preferably, the fan bracket 100 is connected to the outer casing 600 by screws. The fast assembly and disassembly of the fan bracket 100 and the outer casing 600 can be realized through the screw connection, and the assembly and disassembly efficiency of the fan assembly can be improved.

The utility model also provides another embodiment of a microwave oven. According to the embodiment of the utility model, referring to FIG.

As shown in FIG. 7 , a turntable motor 52 is installed on the bottom surface of the inner cavity 500 and a magnetron 51 is installed on the side, which is beneficial for the microwave oven to heat the food in the inner cavity and realize the microwave heating function of the microwave oven. The outer shell 600 covers the inner cavity 500 , and an upper cavity 501 above the inner cavity and a side cavity 502 on the side of the inner cavity are defined between the outer shell 600 and the inner cavity 500 . It is beneficial to protect the various components in the microwave oven. The base 700 is disposed below the inner cavity 500 , and a lower cavity 503 located below the inner cavity 500 is defined between the base 700 and the inner cavity 500 . The fan assembly 800 is arranged in the side cavity 502 and is suitable for blowing air to the magnetron 51 and the turntable motor 52, wherein at least a part of the magnetron 51 is located in the side cavity 502, and at least a part of the turntable motor 52 is located in the lower cavity 503 , the side cavity 502 is spaced apart from the upper cavity 501 , and the side cavity 502 communicates with the lower cavity 503 . Wherein the fan assembly is the above-mentioned fan assembly for a microwave oven, the fan assembly is arranged in the side cavity and is suitable for blowing air to the magnetron and the turntable motor, which is beneficial to the heat dissipation of the magnetron and the turntable motor, and the side cavity and the upper cavity The separation is beneficial to redistribute the air volume, so that the wind of the fan assembly is concentrated in the side cavity and the lower cavity, which is beneficial to the heat dissipation of the turntable motor, and can further increase the heat dissipation performance of the microwave oven. At least a part of the magnetron is located in the side cavity, which helps to increase the overall heating performance of the microwave oven, so that the food in the microwave oven is heated more quickly and evenly.

In addition, in the present application, it is preferable to adopt the air outlet from the lower cavity, so as to improve the heat dissipation effect of the microwave oven.

Further, an air inlet 601 opposite to the fan assembly 800 is formed on the outer casing 600 , and an air outlet 701 is formed on the base 700 . The wind entering from the air inlet mainly flows to the air outlet on the base, which is beneficial to the heat dissipation of the chassis motor.

Preferably, a sponge 53 is provided on the upper part of the inner cavity 500 , and the sponge 53 is separated from the side cavity 502 and the upper cavity 501 . By separating the side cavity and the upper cavity with a sponge, on the one hand, the wind in the microwave oven can be concentrated in the side cavity and the lower cavity, and flow into the lower cavity, which is beneficial to increase the heat dissipation of the components in the side cavity and the lower cavity, and improve the overall efficiency of the microwave oven. Excellent heat dissipation performance; on the other hand, due to the low cost of the sponge, the microwave oven does not increase the raw material cost of the microwave oven while increasing the heat dissipation performance.

The microwave oven of the present application also includes other components such as a controller, which will not be described in detail in the present application, which is understandable to those skilled in the art.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structures, materials or features are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and should not be construed as limitations of the present invention, and those skilled in the art are within the scope of the present invention. Variations, modifications, substitutions and variations can be made to the above-described embodiments.

Claims (10)

1. A microwave oven, characterized in that, comprising: An inner cavity, the bottom surface of the inner cavity is equipped with a turntable motor and a magnetron is installed on the side; an outer shell, the outer shell is covered on the inner cavity, and an upper cavity above the inner cavity and a side cavity on the side of the inner cavity are defined between the outer shell and the inner cavity; a base, the base is arranged below the inner cavity, and a lower cavity below the inner cavity is defined between the base and the inner cavity; a fan assembly, the fan assembly is arranged in the side chamber and is suitable for blowing air to the magnetron and the turntable motor, wherein at least a part of the magnetron is located in the side chamber, the At least a part of the turntable motor is located in the lower chamber, the side chamber is spaced apart from the upper chamber, and the side chamber communicates with the lower chamber. 2 . The microwave oven according to claim 1 , wherein an air inlet opposite to the fan assembly is formed on the outer casing, and an air outlet is formed on the base. 3 . 3 . The microwave oven according to claim 1 , wherein a sponge is provided on the upper part of the inner cavity, and the sponge is spaced apart from the side cavity and the upper cavity. 4 . 4. The microwave oven according to claim 1, wherein the fan assembly comprises: fan bracket; An annular air guide ring, the air inlet end of the air guide ring is connected to the fan bracket; A fan, the fan is rotatably mounted on the fan bracket, and the wind guide ring is arranged around the fan, the air outlet end of the fan protrudes from the air outlet end of the air guide ring, and the The ratio of the distance L between the end surface of the air outlet end of the fan and the end surface of the air outlet end of the wind guide ring to the axial width A of the fan is in the range of 23% to 27%; A motor, the motor is installed on the fan bracket and connected with the fan to drive the fan to rotate. 5. The microwave oven according to claim 4, characterized in that, the blade end of the fan is spaced a predetermined distance from the inner peripheral surface of the air guide ring, and the blade end of the fan is spaced from the inner peripheral surface of the air guide ring. The ratio of the gap H between the peripheral surfaces to the diameter B of the circumference where the blade ends of the fan are located is in the range of 3% to 5%. 6. The microwave oven according to claim 4 or 5, characterized in that, the air inlet end of the air guide ring is formed with an outward rounded corner, and the radius R of the round corner of the air inlet end of the air guide ring is in relation to the The ratio of the diameter B of the circumference where the fan blade ends are located is in the range of 7% to 10%. 7. The microwave oven according to claim 6, wherein the distance L between the end surface of the air outlet end of the fan and the end surface of the air outlet end of the air guiding ring is 7 mm, and the axial width A of the fan is 28 mm. mm, the gap H between the blade end of the fan and the inner peripheral surface of the air guiding ring is 4.5 mm, the diameter B of the circumference where the blade end of the fan is located is 118 mm, and the air inlet of the air guiding ring The fillet radius R at the end is 11 mm. 8. The microwave oven according to claim 4 or 5, wherein the fan comprises: a hub, the hub is in the shape of a column coaxial with the wind guide ring; The paddles are formed on the outer peripheral surface of the hub, and the paddles include a plurality of paddles arranged at intervals in a direction around the hub. 9 . The microwave oven according to claim 8 , wherein the paddles comprise five, and the five paddles are equidistantly arranged in a direction around the hub. 10. The microwave oven according to claim 4, wherein the fan bracket comprises: a skeleton, the skeleton is provided with a through hole; A bracket, the bracket is connected to the skeleton, and the bracket has at least one positioning column for motor installation; Wherein, the periphery of the air inlet end of the air guide ring is connected to the periphery of the through hole, the fan is rotatably connected to the bracket, and the fan and the motor are located on the bracket along the guide. Opposite sides in the axial direction of the wind circle.