Magnetron and microwave heating equipment

Abstract

A magnetron and microwave heating device, wherein the magnetron includes a tube core (21), a first tube shell (21a), a second tube shell (21b), an output ceramic (22), an antenna cap (23), and an antenna (24), wherein the first tube shell (21a), the tube core (21), the second tube shell (21b), the output ceramic (22), and the antenna cap (23) are connected in sequence, and the antenna (24) enters the tube core (21), and then enters the antenna cap (23) sequentially through the second tube shell (21b) and the output ceramic (22), and a height H1 of the second tube shell (21b) relative to the tube core (21) is 14 mm or less, and a ratio H1 / S of the height H1 of the tube core (21) to a cross-sectional area S of the antenna (24) is within a range of 0.4 to 3.3.

Description

[Technical Field]

[0001] The present application relates to the technical field of heating devices, and in particular to magnetrons and microwave heating devices including such magnetrons. [Background technology]

[0002] A magnetron is a vacuum electron tube that generates microwaves, and because of its high vibration efficiency and large microwave output, it is widely used as a microwave source for microwave application devices such as household microwave ovens and industrial microwave heating devices. As a relatively mature microwave source, a magnetron is subject to strict restrictions on its structure and size. Therefore, in devices that use a magnetron to generate microwaves, the magnetron's large volume adversely affects the volume of the device. Summary of the Invention [Problem to be solved by the invention]

[0003] One objective of the present application is to propose a magnetron that achieves miniaturization of the magnetron by redesigning the size of the magnetron while reducing the impact on the output efficiency of the magnetron.

[0004] Another object of the present application is to propose a microwave heating device including the above magnetron. [Means for solving the problem]

[0005] According to the magnetron of the embodiment of the present application, it comprises a tube core, a first tube shell, a second tube shell, an output ceramic, an antenna cap and an antenna, the first tube shell, the tube core, the second tube shell, the output ceramic and the antenna cap are connected in sequence, the antenna enters the tube core, and then enters the antenna cap 23 through the second tube shell and the output ceramic 22, the height H1 of the second tube shell relative to the tube core is 14 mm or less, and the ratio H1 / S of the height H1 of the tube core to the cross-sectional area S of the antenna is in the range of 0.4 to 3.3.

[0006] According to the magnetron of the embodiment of the present application, the size of the tube core is reduced, thereby realizing a compact design of the magnetron, and by setting the ratio between the height of the tube core and the height of the output ceramic, the output efficiency of the magnetron can be guaranteed and energy loss can be reduced.

[0007] The magnetron of the above embodiment of the present invention can have the following additional technical features.

[0008] Optionally, the ratio H1 / S of the height H1 of the pipe core to the cross-sectional area S of the antenna is in the range of 1.5 to 1.7.

[0009] Optionally, the height of the first tube shell relative to the tube core is equal to or less than the height of the second tube shell relative to the tube core.

[0010] Optionally, the first tube shell and the second tube shell both include a tube body portion and a plate body portion, the plate body portion covers the end of the tube core, and the plate body portion is provided with a protrusion for supporting a magnetic portion that fits into the tube body portion so that there is a gap between the magnetic portion and the plate body portion.

[0011] Optionally, the magnetron further includes a housing and a heat dissipation component, the core is disposed inside the housing, and the heat dissipation component is connected between the core and the housing.

[0012] Optionally, the heat dissipation component includes a connection portion, a first branch portion, and a second branch portion, the connection portion is connected to the pipe core, the first branch portion is connected to the connection portion and extends at an angle to connect to the housing, the second branch portion is connected to the connection portion and extends at an angle to connect to the housing, and the first branch portion and the second branch portion extend at an angle in opposite directions.

[0013] Optionally, a first fold is provided at the connection portion, and the first fold is in close contact with the outer surface of the pipe core, and a second fold is provided at both the first branch portion and the second branch portion, and the second fold is in close contact with the inner surface of the housing.

[0014] Optionally, the antenna is configured as an elongated shape with a circular, elliptical or rectangular cross section.

[0015] According to an embodiment of the microwave heating device of the present application, the microwave heating device includes an inner pot and a magnetron, has a cooking chamber inside the inner pot, a microwave passage is provided in the wall of the inner pot, the magnetron is provided outside the inner pot, and the magnetron is suitable for providing microwaves into the inner pot through the microwave passage, and the magnetron is the magnetron described above.

[0016] Optionally, the microwave passage is configured in a horn-like shape with a cross-sectional area that gradually increases in a direction toward the cooking chamber.

[0017] Optionally, the output ceramic and the antenna cap extend into the microwave passage. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram of a magnetron according to one embodiment of the present application. [Figure 2] FIG. 1 is a schematic diagram of a magnetron according to one embodiment of the present application. [Figure 3] FIG. 3 is a local enlarged schematic view of the area surrounded by a circle A in FIG. 2. [Figure 4] 1 is a schematic diagram of a microwave heating device according to an embodiment of the present application. [Figure 5] FIG. 2 is a schematic diagram of H1 / S-power efficiency of a magnetron according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0019] Magnetrons are vacuum electron tubes that generate microwaves. Due to their high vibration efficiency and high microwave output, they are widely used as microwave sources in microwave-related devices, such as household microwave ovens and industrial microwave heaters. As the primary energy source in microwave heaters, the magnetron plays a significant role in the performance of the heater. As shown in Figure 4, the magnetron is installed in the microwave oven's electrical chamber, occupying a large amount of space. This poses a bottleneck in the miniaturization of microwave heaters and significantly limits progress toward miniaturization and increased volume. To achieve further miniaturization, it is necessary to reduce the height of the magnetron. However, miniaturizing the magnetron can easily affect its output efficiency, resulting in energy waste and increased heat generation, which can adversely affect its performance. Therefore, the present application aims to overcome the shortcomings of the prior art by providing a magnetron with a compact energy output structure, and by redesigning the height of the output ceramic, the output height of the magnetron can be reduced while the energy output efficiency is increased to more than 70%, ensuring high-efficiency energy output while also achieving a compact magnetron output structure. The present application provides a magnetron that can achieve a compact magnetron, and while achieving a compact magnetron, can reduce or avoid the impact on the magnetron's output efficiency.

[0020] The following describes in detail the embodiments of the present application, examples of which are shown in the drawings, in which the same or similar reference numerals throughout refer to the same or similar elements or elements having the same or similar functions. The embodiments described with reference to the following drawings are illustrative and are intended to be used to explain the present application, but should not be understood as limiting the present application.

[0021] 1, the magnetron 20 according to the embodiment of the present invention includes a tube core 21, a first tube shell 21a, a second tube shell 21b, an output ceramic 22, an antenna cap 23, and an antenna 24, and the first tube shell 21a, tube core 21, second tube shell 21b, output ceramic 22, and antenna cap 23 are sequentially connected. The antenna 24 enters the tube core 21, passes through the second tube shell 21b and output ceramic 22, and enters the antenna cap 23. The height H1 of the second tube shell 21b relative to the tube core 21 is 14 mm or less, and the ratio H1 / S of the height H1 of the tube core 21 to the cross-sectional area S of the antenna 24 is within a range of 0.4 to 3.3.

[0022] According to the magnetron 20 of the embodiment of the present application, the size of the core 21 is reduced, thereby realizing a compact design of the magnetron 20, and by setting the ratio between the height of the core 21 and the cross-sectional area S of the antenna 24, the output efficiency of the magnetron 20 can be guaranteed and energy loss can be reduced.

[0023] Here, the tube core 21, the second tube shell 21b, the output ceramic 22, and the antenna cap 23 can be arranged in this order along the axial direction of the tube core 21. The antenna 24 penetrates the output ceramic 22 along the axis of the output ceramic 22 and enters the antenna cap 23 along the axis of the antenna cap 23.

[0024] 4, in order to achieve effective microwave conduction in the microwave heating device 100, the size of the microwave passage 102 can hardly be adjusted, and the antenna cap 23 or the antenna cap 23 and the output ceramic 22 can be inserted into the microwave passage 102 to reduce the space occupied by the magnetron 20. The height H1 of the tube core 21 has a decisive influence on the size of the space occupied by the magnetron 20, so this application mainly starts from the height of the tube core 21 to solve the problem of the large space occupied by the magnetron 20, and by setting the height H1 of the tube core 21 to be 14 mm or less, the space occupied by the magnetron 20 can be effectively reduced and the space utilization rate can be improved.

[0025] At the same time, the reduction in the height H1 of the tube core 21 significantly changes the energy output system structure of the magnetron 20, making it difficult for the antenna 24 to transmit energy to the output ceramic 22, which significantly reduces the energy output efficiency and seriously affects the output efficiency of the magnetron 20.

[0026] To solve the impact of the reduction in the height H1 of the tube core 21 on the output efficiency of the magnetron 20, the present application resets the cross-sectional area of ​​the output antenna 24 and the height of the first tube shell 21a. Experiments have shown that the ratio H1 / S of the height H1 of the tube core 21 to the cross-sectional area S of the antenna 24 and the output efficiency of the magnetron 20 show a non-linear change trend. Combining Table 1 and Figure 5, it can be seen that when the ratio H1 / S is within the range of 0.4 to 3.3, the output efficiency of the magnetron 20 can be maintained at 70% or above.

[0027] [Table 1]

[0028] Therefore, in the present application, the height H1 of the tube core 21 is set to 14 mm or less, and the ratio H1 / S of the height H1 of the tube core 21 to the cross-sectional area S of the antenna 24 is set to be between 0.4 and 3.3, which not only ensures the miniaturization of the magnetron 20, but also effectively ensures the output efficiency of the magnetron 20, avoids energy waste, is energy-saving and environmentally friendly, and also avoids the magnetron 20 generating too much heat which would affect its normal operation, thereby improving the operating stability of the miniaturized magnetron 20.

[0029] As can be seen from Table 1 above, when the height H1 of the tube core 21 is 14 mm or less, the relationship between H1 / S and the output efficiency of the magnetron 20 exhibits a non-linear change trend, and when H1 / S is between 1.5 and 1.7, it is possible to ensure that the magnetron 20 has high output efficiency. Therefore, in some embodiments of the present application, the ratio H1 / S of the height H1 of the tube core 21 to the cross-sectional area S of the antenna 24 is in the range of 1.3 to 1.7. This allows the magnetron 20 to be made smaller while also further improving its output efficiency.

[0030] Furthermore, the ratio H1 / S of the height H1 of the pipe core 21 to the cross-sectional area S of the antenna 24 can be set within the range of 1.4 to 1.6.

[0031] Note that the height H1 of the above pipe core 21 may be in millimeters, and the cross-sectional area S of the corresponding antenna 24 may be in square millimeters, where the ratio H1 / S may be in 1 / mm; similarly, the height H1 of the pipe core 21 may be in meters, and the cross-sectional area S of the corresponding antenna 24 may be in square meters, where the ratio H1 / S may be in 1 / m.

[0032] In some embodiments of the present application, the height of the first tube shell 21a is smaller than the height of the second tube shell 21b, thereby further reducing the size of the magnetron 20. Alternatively, the height of the first tube shell 21a can be set to the same as the height of the second tube shell 21b. The heights of the first tube shell 21a and the second tube shell 21b are both heights relative to the tube core 21.

[0033] 3, in some embodiments of the present application, the first tube shell 21a and the second tube shell 21b each include a tube body 211 and a plate body 212. The plate body 212 covers the end of the tube core 21, and the plate body 212 is provided with a protrusion 213 for supporting the magnetic part fitted to the tube body 211 so that there is a gap between the magnetic part and the plate body 212. The supporting effect of the protrusion 213 allows a gap to be formed between the magnetic part 27 and the plate body 212, so that airflow can pass through the gap between the magnetic part 27 and the plate body 212, carrying heat through the airflow, thereby reducing the heat conduction rate between the magnetic part 27 and the end cap, while also improving the heat dissipation efficiency of the magnetic part 27, and more effectively controlling the temperature and rate of temperature rise of the magnetic part 27.

[0034] Here, the tube body 211 may include two, three, or more protrusions 213. For example, multiple sets of protrusions 213 may be provided at intervals along the circumferential direction of the magnetic component 27, with each set including at least one protrusion 213. In this way, the multiple protrusions 213 can provide stable support for the magnetic component 27 and facilitate the creation of a gap between the magnetic component 27 and the end cap, thereby increasing the thermal resistance between the magnetic component 27 and the end cap and improving the heat dissipation effect for the magnetic component 27. The thermal insulation structure may also include multiple sets of concentric protrusions 213, with each set including multiple protrusions 213 provided along the circumferential direction of the magnetic component 27. Adjacent sets may have the same or different numbers of protrusions 213. The applicant of the present application analyzed the number of protrusions 213 to be installed, and found that when the number of protrusions 213 is four or three, the temperature rise of the magnetic component 27 is slowest and the demagnetization rate of the magnetic component 27 is lowest; in particular, when the number of protrusions 213 is three, the temperature rise of the magnetic component 27 is slowest and the demagnetization rate is lowest. This is because when three or four protrusions 213 are installed, a minimum number of protrusions 213 is used to provide stable support for the magnetic component 27.

[0035] Specifically, the protrusions 213 can be supported within a region between the inner circumferential surface and the outer circumferential surface of the magnetic component 27. Preferably, the protrusions 213 are supported at a position along a predetermined proportion from the inner circumferential surface to the outer circumferential surface of the magnetic component 27, which may be within a range of 1 / 3 to 2 / 3. For example, the protrusions 213 are supported at a position along 1 / 2 from the inner circumferential surface to the outer circumferential surface of the magnetic component 27. In this way, the gap between the magnetic component 27 and the plate main body 212 is further increased, thereby providing a stable gap between each part of the magnetic component 27 and the plate main body 212, further weakening the conduction of heat while also making it easier for the magnetic component 27 to dissipate heat.

[0036] The protrusions 213 are configured in a truncated cone shape, and the radial size of the protrusions 213 gradually decreases in a direction away from the surface of the plate body 212, with the peripheral edge of the protrusions 213 being chamfered and / or the end face of the protrusions 213 being recessed inward. This further reduces the contact area between the plate body 212 and the magnetic component 27, further slowing down the heat conduction rate. Also, the similar gap between the protrusions 213 and the magnetic component 27 makes it easier for air to circulate and dissipate heat, improving the heat dissipation effect and further slowing down the rate at which the temperature of the magnetic component 27 rises.

[0037] Note that if the gap between the magnetic component 27 and the plate body 212 is too large or too small, it may affect the stable operation of the magnetic component 27. Therefore, in this application, the height of the protrusion 213 protruding from the surface of the plate body 212 is within the range of millimeters to millimeters, so that a gap of 1 to 2 millimeters is provided between the magnetic component 27 and the surface of the plate body 212. Of course, depending on the actual usage situation, the gap between the magnetic component 27 and the surface of the plate body 212 may be smaller than 1 millimeter or larger than 2 millimeters. This is adjusted according to actual heat dissipation and energy efficiency requirements. For example, a gap of 0.5 millimeters, 1 millimeter, 2 millimeters, 4 millimeters, 5 millimeters, 10 millimeters, etc. may be provided between the magnetic component 27 and the surface of the plate body 212.

[0038] Alternatively, a heat insulating layer may be sprayed on the surface of the magnetic component 27 facing the plate body 212. By providing a heat insulating layer between the magnetic component 27 and the plate body 212, the thermal resistance can be more effectively increased and the rate of heat conduction can be reduced, thereby achieving the effect of reducing the rate at which the temperature of the magnetic component 27 rises.

[0039] Similarly, if the gap between the magnetic component 27 and the plate body 212 is too large or too small, it may affect the stable operation of the magnetic component 27. Therefore, the thickness of the insulating layer is within the range of 1 to 2 mm. Of course, depending on the actual usage situation, the gap between the magnetic component 27 and the surface of the plate body 212 may be smaller than 1 mm or larger than 2 mm. This is adjusted according to the actual heat dissipation and energy efficiency requirements. For example, the gap between the magnetic component 27 and the surface of the plate body 212 may be 0.5 mm, 0.7 mm, 2.1 mm, 2.3 mm, 2.5 mm, 3 mm, etc.

[0040] In some examples of the present application, a heat insulating layer is provided on the surface of the magnetic component 27 facing the plate body 212, and protrusions 213 are provided on the plate body 212, with the protrusions 213 abutting against the heat insulating layer. By providing the heat insulating layer and the protrusions 213, a predetermined gap can be created between the magnetic component 27 and the plate body 212, ensuring that there is a gap between the magnetic component 27 and the plate body 212 to allow airflow to pass through, and heat insulating can be achieved using the heat insulating layer. This improves the heat insulating and heat dissipation effects and further reduces the rate of temperature rise. The total thickness of the heat insulating layer and the protrusions 213 may be within a range of 1 to 2 millimeters.

[0041] In some examples of the present application, a heat insulating layer is provided on the surface of the magnetic component 27 facing the plate body 212, and protrusions 213 are provided on the plate body 212, with the heat insulating layer covering part of the surface of the magnetic component 27 and the protrusions 213 abutting another part of the surface of the magnetic component 27. Similarly, by providing the heat insulating layer and the protrusions 213, a predetermined gap can be created between the magnetic component 27 and the plate body 212, and a gap between the magnetic component 27 and the plate body 212 can be ensured to allow airflow therethrough, and the heat insulating layer can be used to provide insulation. This improves the heat insulation and heat dissipation effect and further reduces the rate of temperature rise. Here, the thickness of the heat insulating layer and the height of the protrusions 213 can both be within the range of millimeters to millimeters.

[0042] In some embodiments of the present application, there is a gap between the inner circumferential surface of the magnetic component 27 and the outer circumferential surface of the tube shell, which separates the magnetic component 27 from the tube shell, reducing heat conduction between the tube shell and the magnetic component 27 and further slowing down the rate of temperature rise of the magnetic component 27. In addition, the gap between the inner circumferential surface of the magnetic component 27 and the outer circumferential surface of the tube shell may be empty or filled with a heat insulating layer, or a structure such as a protrusion 213 may be installed between the magnetic component 27 and the tube shell to achieve heat insulation.

[0043] In this application, the heat dissipation of the magnetron 20 is redesigned to significantly reduce the temperature rise of the magnet heat-receiving surface, and a heat insulating coating can be sprayed on the magnet heat-receiving surface to reduce the heat conduction of the vacuum tube to the magnet.

[0044] 2, in some embodiments of the present application, the magnetron 20 further includes a housing 25 and a heat dissipation component 26, the core 21 is disposed inside the housing 25, and the heat dissipation component 26 is connected between the core 21 and the housing 25. The heat dissipation component 26 can realize effective heat dissipation for the core 21 and provide the magnetron 20 with a stable operating environment.

[0045] 2, the heat dissipation component 26 includes a connecting portion 261, a first branch portion 262, and a second branch portion 263. The connecting portion 261 is connected to the pipe core 21, the first branch portion 262 is connected to the connecting portion 261 and extends at an angle so as to be connected to the housing 25, the second branch portion 263 is connected to the connecting portion 261 and extends at an angle so as to be connected to the housing 25, and the first branch portion 262 and the second branch portion 263 extend at an angle in opposite directions.

[0046] Here, a first fold 264 is provided at the connection portion 261, and the first fold 264 is in close contact with the outer surface of the pipe core 21. A second fold 265 is provided at both the first branch portion 262 and the second branch portion 263, and the second fold 265 is in close contact with the inner surface of the housing 25. This can improve the heat conduction effect between the heat dissipation component 26 and the pipe core 21 and the housing 25, and further enhance the heat dissipation effect for the pipe core 21.

[0047] In some embodiments of the present application, the antenna 24 is configured as an elongated shape with a circular, elliptical or rectangular cross section, which increases the efficiency and effectiveness of microwave conduction and ensures the performance of the magnetron 20.

[0048] As shown in Figures 1 to 4, the microwave heating device 100 of the embodiment of the present application includes an inner pot 10 and a magnetron 20, has a cooking chamber 101 in the inner pot 10, has a microwave passage 102 on the wall of the inner pot 10, and has a magnetron 20 installed outside the inner pot 10, and the magnetron 20 is suitable for providing microwaves into the inner pot 10 through the microwave passage 102, and the magnetron 20 is the magnetron 20 described above.

[0049] As shown in FIGS. 1 and 2, the magnetron 20 includes a tube core 21, a heat dissipation system, a magnetic path system, a filter system, an energy output system, etc. The energy output system includes components such as a second tube shell 21b, an output ceramic 22, an antenna cap 23, an antenna 24, and an exhaust pipe. The cross-sectional shape of the antenna 24 is not limited and may be circular, elliptical, rectangular, etc. One end of the antenna 24 is connected to an arbitrary blade on the tube core 21 (anode component), and the other end passes through a hole in the magnetic component 27, passes through the tube shell and the output ceramic 22, and is finally connected to the exhaust pipe. Electromagnetic wave energy generated by the tube core 21 reaches the output ceramic 22 through the component formed by the tube shell as the outer conductor and the antenna 24 as the inner conductor. The antenna cap 23 serves as a microwave matching component, and the energy is finally output to the outside of the magnetron 20, completing the energy output process.

[0050] The technical solution of this application is an energy output system consisting of a second tube shell 21b (metal shell), an output ceramic 22, an antenna cap 23, an antenna 24, and an exhaust pipe. The height H1 of the second tube shell 21b is the distance between the lower surface of the tube core 21 and the upper surface of the output ceramic 22, and S is the cross-sectional area of ​​the antenna 24. When the height H1 of the second tube shell 21b is less than 14 mm, the cross-sectional area S of the antenna 24 and the height H1 of the second tube body are changed synchronously, thereby solving the efficiency reduction problem caused by lowering the height of the second tube shell 21b and improving the output efficiency of the magnetron 20. Specifically, when the height H1 of the second tube shell 21b is less than 14 mm, the ratio of the height H1 of the second tube shell 21b to the cross-sectional area S of the antenna 24 is 0.4

[0051] According to the microwave heating device 100 of the embodiment of the present application, by installing the above-mentioned magnetron 20, the space occupied by the magnetron 20 can be reduced, and the microwave heating device 100 can be made smaller or the volume of the cooking chamber 101 can be increased, thereby ensuring the heating performance of the magnetron 20. In other words, not only can the microwave heating device 100 be made smaller and have a larger volume, but it can also improve energy utilization and reduce energy waste, making it energy-saving and environmentally friendly.

[0052] As shown in Figure 4, in some embodiments of the present application, the microwave passage 102 is configured in a horn shape with a cross-sectional area that gradually increases in the direction toward the cooking chamber 101. This allows more microwaves to be transferred into the inner pot 10, effectively improving the heating efficiency of the microwave heating device 100.

[0053] ​1, in some embodiments of the present application, the output ceramic 22 and the antenna cap 23 are inserted into the microwave passage 102. This can improve the microwave transmission efficiency and effectiveness, and can also reduce the space occupied by the magnetron 20, thereby improving space utilization.

[0054] Additionally, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to specify the number of technical features being indicated. Thus, a feature qualified as "first" or "second" may indicate or imply the inclusion of at least one of that feature. In the description herein, "plurality" means at least two, e.g., two, three, etc., unless otherwise clearly and specifically limited.

[0055] In this application, unless otherwise expressly specified and limited, the terms "attached," "coupled," "connected," "fixed," etc. should be interpreted broadly, and may refer to, for example, a fixed connection, a detachable connection, or integration, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediary, an internal communication between two components, or an interactive relationship between two components. Those skilled in the art can understand the specific meanings of the above terms according to specific circumstances.

[0056] In this application, unless otherwise expressly specified and limited, when a first feature is "above" or "below" a second feature, it may mean that the first feature and the second feature are in direct contact or indirect contact via an intermediary. Furthermore, when a first feature is "above," "upper," or "on top" of a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or that the first feature is at a higher horizontal height than the second feature. When a first feature is "below," "below," or "on the bottom" of a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or that the first feature is at a lower horizontal height than the second feature.

[0057] In the description herein, reference to the reference terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific feature, structure, material, or characteristic described in the relevant embodiment or example is included in at least one embodiment or example of the present application. The exemplary use of the above terms in the description herein does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any embodiment or example. Furthermore, if not mutually inconsistent, a person skilled in the art may combine different embodiments or examples and features of different embodiments or examples described herein.

[0058] Although the above has already shown and described embodiments of the present application, the above embodiments are merely illustrative and should not be construed as limitations on the present application. Those skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application. [Explanation of symbols]

[0059] 100 Microwave heating device 10 Inner pot 101 Cooking Chamber 102 Microwave Passage 20 Magnetron 21 Tube core 21a First tube shell 21b Second tube shell 211 Pipe body 212 Plate body 213 Protrusion 22 Output Ceramic 23 Antenna cap 24 Antenna 25 Housing 26 Heat dissipation parts 261 Connection 262 First Branch 263 Second Branch 264 First Turn 265 Second Turn 27 Magnetic parts

Claims

1. A magnetron comprising a tube core (21), a first tube shell (21a), a second tube shell (21b), an output ceramic (22), an antenna cap (23), and an antenna (24), wherein the first tube shell (21a), the tube core (21), the second tube shell (21b), the output ceramic (22), and the antenna cap (23) are connected in sequence; The antenna (24) enters the tube core (21), passes through the second tube shell (21b), the output ceramic (22), and enters the antenna cap (23). A magnetron characterized in that a height H1 of the second tube shell (21b) relative to the tube core (21) is 14 mm or less, and a ratio H1 / S of the height H1 of the tube core (21) to a cross-sectional area S of the antenna (24) is in a range of 0.4 to 3.

3.

2. 2. The magnetron according to claim 1, wherein a ratio H1 / S of a height H1 of the tube core (21) to a cross-sectional area S of the antenna (24) is in the range of 1.5 to 1.

7.

3. 2. The magnetron according to claim 1, wherein the height of the first tube shell (21a) relative to the tube core (21) is equal to or less than the height of the second tube shell (21b) relative to the tube core (21).

4. 2. The magnetron according to claim 1, wherein the first tube shell (21a) and the second tube shell (21b) each include a tube body portion (211) and a plate body portion (212), the plate body portion (212) covers an end of the tube core (21), and the plate body portion (212) is provided with a protrusion (213) for supporting the magnetic portion fitted to the tube body portion (211) so that there is a gap between the magnetic portion and the plate body portion (212).

5. The magnetron (20) further includes a housing (25) and a heat dissipation part (26). The core (21) is disposed inside the housing (25). The heat dissipation part (26) is connected between the core (21) and the housing (25). The heat dissipation part (26) includes a connecting part (261), a first branch part (262) and a second branch part (263). The connecting part (261) and the core (21) 2. The magnetron according to claim 1, wherein the first branch portion (262) is connected to the connecting portion (261) and extends at an angle so as to be connected to the housing (25), the second branch portion (263) is connected to the connecting portion (261) and extends at an angle so as to be connected to the housing (25), and the first branch portion (262) and the second branch portion (263) extend at an angle in opposite directions.

6. 6. The magnetron according to claim 5, wherein the connecting portion (261) is provided with a first fold (264), which is in close contact with the outer surface of the tube core (21), and the first branch portion (262) and the second branch portion (263) are both provided with a second fold (265), which is in close contact with the inner surface of the housing (25).

7. 2. The magnetron of claim 1, wherein the antenna (24) is configured as an elongated shape with a circular, elliptical or rectangular cross section.

8. A microwave heating device, It includes an inner pot (10) and a magnetron (20), The inner pot (10) has a cooking chamber (101) therein, and a microwave passage (102) is provided in the wall of the inner pot (10); 8. A microwave heating device, wherein the magnetron (20) is provided outside the inner pot (10), the magnetron (20) is suitable for providing microwaves into the inner pot (10) through the microwave passage (102), and the magnetron (20) is the magnetron (20) according to any one of claims 1 to 7.

9. 9. The microwave heating device according to claim 8, wherein the microwave passage (102) is configured in a horn-like shape with a cross-sectional area gradually increasing in a direction toward the cooking chamber (101).

10. 9. The microwave heating device according to claim 8, wherein the power ceramic (22) and the antenna cap (23) extend into the microwave passage (102).

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