Cover plate, hot air assembly with same and cooking utensil

Abstract

The cover plate is arranged on one side, in the axial direction, of a centrifugal impeller, the cover plate is provided with a first surface and a second surface which are oppositely arranged in the axial direction of the centrifugal impeller, the first surface is arranged towards the centrifugal impeller, and an air inlet hole and an air outlet hole which penetrate through the cover plate are formed in the cover plate; at least part of the peripheral wall of the air outlet hole forms a first inclined face which is obliquely arranged relative to the axis of the centrifugal impeller, and in the direction from the first surface to the second surface, the inclination direction of the first inclined face is the same as the inclination direction of blades of the centrifugal impeller. According to the cover plate disclosed by the invention, the inclined first inclined surface is arranged at the air outlet hole, and the inclined direction of the first inclined surface is the same as that of the blades of the centrifugal impeller, so that the inclined direction of the first inclined surface is the same as the air flow movement direction, and the air flow can have the radial rotation speed as much as possible when flowing out of the air outlet hole; therefore, the air outlet speed can be increased, and the cooking effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of household appliances, in particular to a cover plate and a hot air component and a cooking utensil having the cover plate. Background Art

[0002] At present, the main form of the hot air structure of cooking utensils is to arrange a circle of heating tubes around the centrifugal fan. When the motor rotates, the center of the centrifugal fan draws air, and the air is thrown to the heating tube through the blades. After being heated by the heating tube, it forms hot air, and then enters the cavity through the small holes of the hot air component to heat the food in the cavity. However, the conversion rate of the motor power of the hot air structure into the air volume at the air outlet is extremely low, and the air flow rate entering the cooking cavity is extremely slow, which leads to the problem of long cooking time and poor cooking effect. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a cover plate, which can make the airflow have as much radial rotation speed as possible when it flows out of the air outlet, thereby increasing the air outlet speed, thereby accelerating the heating speed of the cooking utensil and improving the cooking effect; at the same time, it can also reduce the energy loss of the centrifugal impeller, thereby improving the air outlet efficiency, accelerating the cooking speed and reducing energy consumption.

[0004] The present invention also provides a hot air assembly having the cover plate.

[0005] The present invention also provides a cooking utensil having the hot air component.

[0006] According to the first aspect of the present invention, the cover plate is arranged on one side of the centrifugal impeller in the axial direction, and the cover plate has a first surface and a second surface arranged opposite to each other in the axial direction of the centrifugal impeller, the first surface is arranged toward the centrifugal impeller, and an air inlet hole and an air outlet hole passing through the cover plate are formed on the cover plate, at least a portion of the peripheral wall of the air outlet hole is formed as a first inclined surface inclined relative to the axis of the centrifugal impeller, and in the direction from the first surface toward the second surface, the inclination direction of the first inclined surface is the same as the inclination direction of the blades of the centrifugal impeller.

[0007] According to the cover plate of the present invention, by arranging an inclined first slope at the air outlet, and arranging the inclination direction of the first slope to be the same as the inclination direction of the blades of the centrifugal impeller, the inclination direction of the first slope can be made the same as the direction of air flow movement, thereby making the air flow have as much radial rotation speed as possible when flowing out of the air outlet, thereby increasing the air outlet speed, thereby accelerating the heating speed of the cooking utensil and improving the cooking effect; at the same time, it can also reduce the energy loss of the centrifugal impeller, thereby improving the air outlet efficiency, accelerating the cooking speed and reducing energy consumption.

[0008] According to some embodiments of the present invention, the angle between the first inclined surface and a plane perpendicular to the axis of the centrifugal impeller is 21°-35°.

[0009] According to some embodiments of the present invention, a flange is provided at the periphery of the air outlet, and in a direction from the first surface toward the second surface, the flange extends obliquely outward along the radial direction of the centrifugal impeller.

[0010] According to some embodiments of the present invention, in the radial direction from inside to outside of the centrifugal impeller, the air outlet is an arc-shaped hole extending obliquely along the circumference of the centrifugal impeller, and the inclination direction of the arc-shaped hole is the same as the inclination direction of the blades of the centrifugal impeller.

[0011] According to some embodiments of the present invention, there are multiple air outlet holes, and the multiple air outlet holes are arranged at intervals around the centrifugal impeller.

[0012] According to some embodiments of the present invention, a ratio of a total flow cross-sectional area of ​​the air inlet holes to a total flow cross-sectional area of ​​the air outlet holes is 1.2-3.5.

[0013] According to some embodiments of the present invention, there are multiple air inlet holes, and the multiple air inlet holes are arranged around the axis of the centrifugal impeller.

[0014] According to some embodiments of the present invention, the cover plate includes: a bottom plate portion, which is a plate body and is arranged perpendicular to the central axis of the centrifugal impeller, and the air outlet is formed on the bottom plate portion; a side plate portion, which extends in a ring shape along the circumference of the bottom plate portion, one end of the side plate portion is connected to the circumference of the bottom plate portion and the other end extends along the axial direction of the centrifugal impeller, and the side plate portion cooperates with the bottom plate portion to define a cavity for accommodating the centrifugal impeller; a side plate portion, which is connected to the other end of the side plate portion and extends outward away from the bottom plate portion in a plane perpendicular to the central axis of the centrifugal impeller, and a fixing hole for fixing the cover plate is formed on the side plate portion.

[0015] According to some embodiments of the present invention, the cover plate is integrally formed.

[0016] The hot air assembly according to the second aspect of the present invention comprises a centrifugal impeller, a heating element and a cover plate according to the first aspect of the present invention, wherein the centrifugal impeller is arranged on the side where the first surface of the cover plate is located, and the heating element is arranged around the centrifugal impeller.

[0017] According to the hot air assembly of the present invention, the cover plate of the first aspect is provided, thereby improving the overall performance of the hot air assembly.

[0018] The cooking appliance according to the third aspect of the present invention comprises a cavity and a hot air assembly according to the second aspect of the present invention, wherein the cavity has a cooking cavity, and the air outlet is connected to the cooking cavity.

[0019] According to the cooking appliance of the present invention, the hot air assembly of the second aspect is provided, thereby improving the overall performance of the cooking appliance.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a cover plate according to an embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of a cover plate according to another angle of an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of a centrifugal impeller according to an embodiment of the present invention;

[0024] Figure 4 is a schematic diagram of a centrifugal impeller from another angle according to an embodiment of the present invention.

[0025] Reference numerals:

[0026] 10. cover plate; 11. bottom plate; 111. air inlet; 112. air outlet; 1121. first inclined surface; 12. side plate; 121. through hole; 13. side plate; 131. fixing hole;

[0027] 20. Centrifugal impeller; 21. Blades; 22. Bottom plate; 221. Mounting boss; 222. Connecting plate portion; 2221. Connecting piece; 223. Reinforcing rib; 224. Shaft hole. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0029] Reference below Figure 1 and Figure 4 A cover plate 10 according to an embodiment of a first aspect of the present invention will be described.

[0030] like Figure 1As shown, according to the cover plate 10 of the first aspect of the present invention, the cover plate 10 is arranged on one side of the centrifugal impeller 20 in the axial direction, and the cover plate 10 has a first surface and a second surface which are arranged relatively to each other in the axial direction of the centrifugal impeller 20, and the first surface is arranged toward the centrifugal impeller 20, and an air inlet hole 111 and an air outlet hole 112 which pass through the cover plate 10 are formed on the cover plate 10, and at least a part of the peripheral wall of the air outlet hole 112 is formed as a first inclined surface 1121 which is inclined relative to the axis of the centrifugal impeller 20, and in the direction from the first surface toward the second surface, the inclination direction of the first inclined surface 1121 is the same as the inclination direction of the blades 21 of the centrifugal impeller 20.

[0031] Specifically, the cover plate 10 is formed with a receiving cavity, and the centrifugal impeller 20 is arranged in the receiving cavity. The cover plate 10 is used to isolate the centrifugal impeller 20 and other parts, which can improve the safety of the user when using the cooking utensil, and increase the aesthetics and safety of the cooking utensil. The air inlet 111 formed on the cover plate 10 is used for air intake, and can provide air intake for the centrifugal impeller 20; the air outlet 112 is used to discharge the gas accelerated by the centrifugal impeller 20 into the cooking cavity to heat the food in the cooking cavity.

[0032] In some embodiments, part of the peripheral wall of the air outlet 112 is formed as a first inclined surface 1121 inclined relative to the axis of the centrifugal impeller 20 . In other embodiments, all of the peripheral wall of the air outlet 112 is formed as the first inclined surface 1121 . In the direction from the first surface toward the second surface, the inclination direction of the first inclined surface 1121 is the same as the inclination direction of the blades 21 of the centrifugal impeller 20, wherein the gas entering the centrifugal impeller 20 flows out through the air flow channel of the centrifugal impeller 20, and the air flow channel of the centrifugal impeller 20 is the channel between two adjacent blades 21 in the centrifugal impeller 20, and thus the air flow outflow direction is the same as the inclination direction of the blades 21, that is, the inclination direction of the first inclined surface 1121 is the same as the direction of air flow movement, and at the same time, the air intake mode of the centrifugal fan is axial air intake and radial air outlet, that is, the gas itself after being accelerated by the centrifugal fan has a large amount of radial velocity, and the axial velocity is less, but the air outlet mode of the hot air component is axial air suction and axial air outlet, and thus the inclination direction of the first inclined surface 1121 is the same as the direction of air flow movement, so that the air flow can have as much radial rotation speed as possible when it flows out from the air outlet 112, thereby increasing the air outlet speed and improving the cooking effect; at the same time, it can also reduce the energy loss of the centrifugal impeller 20, thereby increasing the air outlet efficiency, speeding up the cooking speed and reducing energy consumption.

[0033] Furthermore, the inclination direction of the blade 21 is divided into three forms relative to the rotation direction of the centrifugal impeller 20, namely, forward, radial and backward, and the centrifugal impeller 20 used in the cooking utensils is mostly in the form of a forward impeller or a backward impeller. Among them, when the centrifugal impeller 20 is a backward impeller, the inclination direction of the blade 21 is opposite to the rotation direction of the centrifugal impeller 20, the airflow flows out along the airflow channel of the centrifugal impeller 20, and then the direction of the airflow movement is opposite to the rotation direction of the centrifugal impeller 20, and is the same as the inclination direction of the blade 21, that is, the inclination direction of the first inclined surface 1121 is the same as the direction of the airflow movement; when the centrifugal impeller 20 is a forward impeller, the inclination direction of the blade 21 is the same as the rotation direction of the centrifugal impeller 20, the airflow flows out along the airflow channel of the centrifugal impeller 20, and then the direction of the airflow movement is the same as the rotation direction of the centrifugal impeller 20, and is also the same as the inclination direction of the blade 21, that is, the inclination direction of the first inclined surface 1121 is the same as the direction of the airflow movement.

[0034] According to the cover plate 10 of the embodiment of the present invention, by setting an inclined first slope 1121 at the air outlet 112, and setting the inclination direction of the first slope 1121 to be the same as the inclination direction of the blades 21 of the centrifugal impeller 20, the inclination direction of the first slope 1121 can be made the same as the direction of airflow movement, so that the airflow can have as much radial rotation speed as possible when flowing out of the air outlet 112, thereby increasing the air outlet speed, thereby accelerating the heating speed of the cooking utensil and improving the cooking effect; at the same time, the energy loss of the centrifugal impeller 20 can be reduced, thereby improving the air outlet efficiency, accelerating the cooking speed and reducing energy consumption.

[0035] According to some embodiments of the present invention, the angle between the first inclined surface 1121 and the plane perpendicular to the axis of the centrifugal impeller 20 is 21°-35°. For example, the angle between the first inclined surface 1121 and the plane perpendicular to the axis of the centrifugal impeller 20 can be 21°, 22°, 23°, 24°, 25°, 26°, 28°, 30°, 32°, 34° or 35°. When the gas passes through the centrifugal impeller 20 to do work, the gas is thrown out of the centrifugal impeller 20 along the tangent direction of the edge of the blade 21 of the centrifugal impeller 20. Therefore, the gas obtains radial velocity after the centrifugal impeller 20 works, and then by setting the angle between the first inclined surface 1121 and the plane perpendicular to the axis of the centrifugal impeller 20 to be 21°-35°, the discharged gas can have the radial velocity after being accelerated by the centrifugal impeller 20, and then the air outlet speed can be increased, thereby improving the cooking effect.

[0036] According to some embodiments of the present invention, a flange is provided on the periphery of the air outlet 112, and in the direction from the first surface toward the second surface, the flange extends obliquely outward along the radial direction of the centrifugal impeller 20. The flange can prevent the radial wind from continuing to move in the original direction, change the wind direction, and thus enable the gas to be discharged from the air outlet 112, thereby increasing the air volume and thus improving the air outlet efficiency.

[0037] Optionally, the flange can be integrally formed with the cover plate 10 , or can be formed as a guide plate fixedly connected to the cover plate 10 .

[0038] According to some embodiments of the present invention, Figure 1-Figure 2 As shown, in the radial direction from inside to outside of the centrifugal impeller 20, the air outlet hole 112 is an arc hole extending obliquely along the circumference of the centrifugal impeller 20, and the inclination direction of the arc hole is the same as the inclination direction of the blades 21 of the centrifugal impeller 20. The gas moves along the circumference of the centrifugal impeller 20 and continues to move in the form of a vortex, and then in the radial direction from inside to outside of the centrifugal impeller 20, the air outlet hole 112 is set to be an arc hole extending obliquely along the circumference of the centrifugal impeller 20, which can increase the air volume of the air outlet hole 112; at the same time, the movement direction of the gas is the same as the inclination direction of the blades 21 of the centrifugal impeller 20, and then the inclination direction of the arc hole is set to be the same as the inclination direction of the blades 21 of the centrifugal impeller 20, which can further increase the air volume and air speed, and thus improve the cooking effect.

[0039] According to some embodiments of the present invention, Figure 1-Figure 2 As shown, there are multiple air outlet holes 112, and the multiple air outlet holes 112 are arranged at intervals around the centrifugal impeller 20. For example, the number of air outlet holes 112 can be two, three or more. Among them, after the gas passes through the centrifugal impeller 20 to do work, the gas is thrown out of the centrifugal impeller 20 along the tangential direction of the edge of the blade 21 of the centrifugal impeller 20, and the gas moves circumferentially along the centrifugal impeller 20 and continues to move in the form of a vortex. Then, multiple air outlet holes 112 are provided and the multiple air outlet holes 112 are arranged at intervals around the centrifugal impeller 20, which can increase the coverage area of ​​the air outlet holes 112, and then increase the flow area of ​​the air outlet, increase the air outlet volume, and thus improve the cooking efficiency of the cooking utensil; at the same time, the multiple air outlet holes 112 are arranged at intervals around the centrifugal impeller 20, and the uniformity of the air outlet can also be improved, and then the heating uniformity of the cooking utensil can be improved, and the cooking effect can be improved.

[0040] According to some embodiments of the present invention, the ratio of the total flow cross-sectional area of ​​the air inlet holes 111 to the total flow cross-sectional area of ​​the air outlet holes 112 is 1.2-3.5. If the total flow cross-sectional area of ​​the air inlet holes 111 is S1 and the total flow cross-sectional area of ​​the air outlet holes 112 is S2, then the ratio of the total flow cross-sectional area of ​​the air inlet holes 111 to the total flow cross-sectional area of ​​the air outlet holes 112 is S1 / S2, and the range of S1 / S2 is [1.2, 3.5]. For example, the value of S1 / S2 can be 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4 or 3.5, that is, the air intake is always greater than the air outlet, so that the gas in the flow channel can be in a pressurized state, and the gas outlet speed can be increased, thereby improving the cooking effect.

[0041] For example, the total flow cross-sectional area ratio of the air inlet 111 and the air outlet 112 of the cover plate 10 of the present application meets the above parameters, and the angle b between the first inclined surface 1121 of the air outlet 112 of the cover plate 10 of the present application and the plane perpendicular to the axis of the centrifugal impeller 20 is in the range of 21°-35°. Under the condition of constant fan and impeller conditions, three groups of simulation experiments are randomly selected from the above parameters, and the experimental data are shown in the following table:

[0042]

[0043] The air outlet efficiency is equal to the product of the air volume and the static pressure and the percentage of the motor shaft power. Specifically, it can be seen from the above table that when the angle b between the first inclined surface 1121 and the plane perpendicular to the axis of the centrifugal impeller 20 is 21°, and the ratio of the total flow cross-sectional area of ​​the air inlet 111 to the total flow cross-sectional area of ​​the air outlet 112 is 1.2, the air outlet speed can reach 6m / s and the air outlet efficiency can reach 82.1%; when the angle b between the first inclined surface 1121 and the plane perpendicular to the axis of the centrifugal impeller 20 is 30°, and the ratio of the total flow cross-sectional area of ​​the air inlet 111 to the total flow cross-sectional area of ​​the air outlet 112 is 2.1 , the air outlet speed can reach 12.5m / s, and the air outlet efficiency can reach 73.6%; when the angle b between the first inclined surface 1121 and the plane perpendicular to the axis of the centrifugal impeller 20 is 35°, and the ratio of the total flow cross-sectional area of ​​the air inlet hole 111 to the total flow cross-sectional area of ​​the air outlet hole 112 is 3.5, the air outlet speed can reach 14.3m / s, and the air outlet efficiency can reach 68.2%; it can be seen that the air outlet speed shows a trend of increasing with the increase of the parameters, and the air outlet efficiency shows a trend of decreasing with the increase of the parameters. Furthermore, the cooking effect of the cooking appliance is related to the air outlet speed and the air outlet efficiency. Experiments have shown that when the angle b between the first inclined surface 1121 and the plane perpendicular to the axis of the centrifugal impeller 20 is 30°, and the ratio of the total flow cross-sectional area of ​​the air inlet holes 111 to the total flow cross-sectional area of ​​the air outlet holes 112 is 2.1, the cooking effect is relatively good. At this time, the air outlet of the hot air component is 2.9 times higher than that in the traditional form, and the air outlet efficiency is increased by 5.74 times year-on-year.

[0044] According to some embodiments of the present invention, Figure 1-Figure 2 As shown, there are multiple air inlet holes 111, and the multiple air inlet holes 111 are arranged around the axis of the centrifugal impeller 20. For example, the number of the multiple air inlet holes 111 can be two, three or more. Among them, the multiple air inlet holes 111 can increase the flow area of ​​the air inlet holes 111, increase the air intake, and then ensure that the air intake meets the air outlet requirements and ensure the normal use of the cooking appliance; at the same time, the multiple air inlet holes 111 are arranged around the axis of the centrifugal impeller 20, so that the air inlet holes 111 can be adapted to the inlet angle of the centrifugal impeller 20, and then the impact loss of the airflow on the blades 21 when the airflow enters the airflow channel of the centrifugal impeller 20 can be reduced, thereby improving the fan efficiency.

[0045] For example Figure 1-Figure 2 As shown, a plurality of air inlet holes 111 are arranged in a ring shape around the axis of the centrifugal impeller 20 , and are arranged in multiple layers from the inside to the outside; a plurality of air outlet holes 112 are arranged around the outside of the plurality of air inlet holes 111 .

[0046] According to some embodiments of the present invention, Figure 1-Figure 2As shown, the cover plate 10 includes: a bottom plate portion 11, a side plate portion 12 and a side plate portion 13. The bottom plate portion 11 is a plate body and is arranged perpendicular to the central axis of the centrifugal impeller 20. The air outlet 112 is formed on the bottom plate 22; the side plate portion 12 extends in a ring shape along the circumference of the bottom plate portion 11. One end of the side plate portion 12 is connected to the circumference of the bottom plate portion 11 and the other end extends along the axial direction of the centrifugal impeller 20. The side plate portion 12 cooperates with the bottom plate portion 11 to define a cavity for accommodating the centrifugal impeller 20; the side plate portion 13 is connected to the other end of the side plate portion 12, and extends outward away from the bottom plate 22 in a plane perpendicular to the central axis of the centrifugal impeller 20. A fixing hole 131 for fixing the cover plate 10 is formed on the side plate portion 13. Among them, the plate body has a simple structure and is easy to manufacture. Using the plate body as the bottom plate portion 11 can reduce the difficulty of producing the bottom plate portion 11, and thus can reduce the production cost of the cover plate 10. At the same time, the air outlet holes 112 and the air inlet holes 111 are both formed on the bottom plate portion 11, which can reduce the difficulty of manufacturing the air outlet holes 112 and the air inlet holes 111, thereby increasing the production speed of the cover plate 10.

[0047] The side plate 12 extends in a ring shape along the circumference of the bottom plate 11, and one end is connected to the bottom plate 11 to form a receiving cavity with one side opening, which is used to receive the centrifugal impeller 20. The air inlet and outlet of the centrifugal impeller 20 are axial air inlet and radial air outlet, and the air inlet hole 111 and the air outlet hole 112 are both provided on the bottom plate 11, and the side plate 12 can also be used to define the air duct and change the wind direction, so that the gas accelerated by the centrifugal impeller 20 can be discharged from the air outlet hole 112, thereby ensuring the normal operation of the cooking appliance.

[0048] The side plate portion 13 is used to be fixedly connected to the inner wall of the cooking utensil. The side plate portion 13 extends outward away from the bottom plate portion 11 in a plane perpendicular to the central axis of the centrifugal impeller 20, so that the side plate portion 13 has a certain width and can be arranged parallel to the inner wall of the cooking utensil, thereby increasing the contact area between the cover plate 10 and the cooking utensil, thereby improving the installation stability of the cover plate 10.

[0049] Optionally, a plurality of through holes 121 are also formed on the side plate portion 12. The through holes 121 pass through both sides of the side plate portion 12, allowing wind to enter the cooking cavity from multiple directions, thereby improving cooking efficiency and uniformity.

[0050] According to some embodiments of the present invention, the cover plate 10 is integrally formed. The integrally formed structure is simple, easy to manufacture, and has high structural strength and stability. Therefore, the cover plate 10 is integrally formed, which can improve the structural stability of the cover plate 10, reduce the production cost of the cover plate 10, and further increase the production speed of the cover plate 10 and reduce the production cost of the cover plate 10; at the same time, the integrally formed cover plate 10 can also reduce the assembly process of the cooking utensils, and further improve the assembly efficiency of the cooking utensils.

[0051] Optionally, the cover plate 10 is a stamped sheet metal part, wherein the cover plate 10 is made by stamping, which is simple to make and can reduce material consumption, thereby reducing the manufacturing cost of the cover plate 10; at the same time, the stamped part is light in weight and has good rigidity, which can reduce the weight of the cover plate 10, thereby reducing the weight of the cooking utensil; in addition, stamping can also form a sheet metal part with better surface quality and a smooth and beautiful appearance, thus, the aesthetics of the cover plate 10 can also be improved.

[0052] The hot air assembly according to the second aspect of the present invention comprises a centrifugal impeller 20, a heating element and a cover plate 10 according to the first aspect of the present invention. The centrifugal impeller 20 is arranged on the side where the first surface of the cover plate 10 is located, and the heating element is arranged around the centrifugal impeller 20.

[0053] The heating element is used to heat and generate high-temperature air, and then heat the food to cook the food. The heating element is arranged around the centrifugal impeller 20, and the heating element and the centrifugal impeller 20 are both arranged on the side where the first surface of the cover plate 10 is located, so that the cover plate 10 can cover the centrifugal impeller 20 and the heating element, thereby improving the aesthetics of the cooking utensil; at the same time, the heating element is arranged around the centrifugal impeller 20, which can improve the heating efficiency of the gas, and thus improve the cooking efficiency.

[0054] When food needs to be heated, the heating element and the centrifugal impeller 20 are turned on. The centrifugal impeller 20 rotates to form a negative pressure, and then the gas is sucked into the impeller from the air inlet hole 111. The gas sucked into the impeller is then discharged after the impeller does work. The discharged gas is heated by the heating element and then discharged into the cooking cavity through the air outlet hole 112, thereby heating the food in the cooking cavity.

[0055] According to the hot air assembly of the present invention, the cover plate 10 of the first aspect is provided, thereby improving the overall performance of the hot air assembly.

[0056] In some specific embodiments, Figure 3-Figure 4 As shown, the centrifugal impeller 20 includes: a bottom plate 22 and a plurality of blades 21, and the bottom plate 22 is provided with an axial hole 224; the plurality of blades 21 are arranged on the bottom plate 22 at intervals along the circumference of the bottom plate 22, and in the radial direction from inside to outside of the centrifugal impeller 20, the blades 21 extend obliquely along the circumference of the centrifugal impeller 20, and the direction of the oblique extension of the blades 21 is opposite to the rotation direction of the centrifugal impeller 20.

[0057] Specifically, the bottom plate 22 provides an installation position and a support function for the blades 21. The blades 21 are connected to the bottom plate 22. The channel between two adjacent blades 21 forms an airflow channel, which is used for gas circulation. An axial hole 224 is provided on the bottom plate 22. The axial hole 224 is circular and is arranged at the center of the bottom plate 22. A plurality of blades 21 are arranged at intervals along the circumference of the bottom plate 22, that is, a plurality of blades 21 are arranged at intervals along the circumference of the axial hole 224. The blades 21 extend obliquely along the circumference of the centrifugal impeller 20, and the oblique extension direction is opposite to the rotation direction of the centrifugal impeller 20 in the radial direction from inside to outside of the centrifugal impeller 20, that is, the centrifugal impeller 20 is a backward impeller. Among them, the air flow velocity at the impeller outlet of the backward impeller is relatively small. When the air flow velocity is low, the friction of the air duct on the air flow is also smaller, thereby reducing the energy loss of the air flow in the process from the air inlet to the air outlet, so that more of the shaft work transmitted by the motor can be converted into the static pressure of the fan. The static pressure of the fan increases, and the greater the static pressure of the fan, the more energy the impeller can transfer to the airflow, thereby improving the efficiency of the fan.

[0058] Furthermore, an axial hole 224 is formed on the bottom plate 22, and the axial hole 224 is arranged at the center position of the bottom plate 22. The axial hole 224 can be assembled with the output axial direction of the driving device. The plurality of blades 21 are arranged at intervals along the circumference of the bottom plate 22, so that the driving device can drive the plurality of blades 21 to rotate by driving the bottom plate 22 to rotate, so that the blades 21 can do work on the airflow and drive the airflow to move.

[0059] In some specific embodiments, the centrifugal impeller 20 satisfies: 0.65≤D2 / D1≤0.75, 39°≤a1≤51°, 51°≤a2≤71°, 8≤n≤12, wherein D2 / D1 is the hub ratio of the centrifugal impeller 20, a1 is the inlet installation angle of the blade 21, a2 is the outlet installation angle of the blade 21, and n is the number of blades 21.

[0060] The hub ratio refers to the ratio of the hub diameter to the impeller diameter. The hub is the part of the impeller connected to the output shaft, and is used to connect the blades 21 and the output shaft. Under a given flow rate, the larger the hub ratio, the greater the output pressure. The output wind pressure of the centrifugal impeller 20 can be changed by changing the hub ratio of the impeller, thereby improving the fan efficiency.

[0061] Specifically, D2 / D1 is the hub ratio of the centrifugal impeller 20, that is, D2 is the diameter of the hub, and D1 is the diameter of the impeller. Figure 3As shown, the distance d2 between the inner end of the blade 21 and the central axis of the base plate 22 is the radius of the hub, wherein the inner end of the blade 21 is the end of the blade 21 close to the central axis of the base plate 22, D2=2×d2; the distance d1 between the outer end of the blade 21 and the axis of the base plate 22 is the radius of the centrifugal impeller 20, wherein the outer end of the blade 21 is the end of the blade 21 away from the shaft hole 224, D1=2×d1, and then the hub ratio of the centrifugal impeller 20 can be obtained by d2 / d1.

[0062] a1 is the inlet installation angle of the blade 21, which is the angle between the tangent line of the circumference at the inlet end of the blade 21 and the blade 21, wherein the inlet end of the blade 21 is the end of the blade 21 close to the shaft hole 224. The airflow direction is related to the inlet installation angle of the blade 21. The airflow direction can be changed by changing the inlet installation angle of the blade 21, reducing the impact loss of the airflow on the blade 21 when entering the airflow channel, thereby improving the fan efficiency.

[0063] Specifically, in a projection plane perpendicular to the central axis of the centrifugal impeller 20, a circle C1 is made with the central axis of the bottom plate 22 as the center O and a line from the center to the inner end of the blade 21 as the radius. The circle C1 and the inner end of the blade 21 form an intersection E1, and then a tangent F1 is made with the intersection E1 as the common intersection point. The angle between F1 and the blade 21 is the inlet installation angle a1 of the blade 21.

[0064] a2 is the outlet installation angle of the blade 21, which is the angle between the tangent line of the circumference of the outlet end of the blade 21 and the blade 21, wherein the outlet end of the blade 21 is the end away from the shaft hole 224. The outflow direction of the airflow is related to the outlet installation angle of the blade 21. The outlet installation angle of the blade 21 can be adjusted to change the airflow direction, thereby reducing the collision between the air and the blade 21, ensuring the smoothness of the gas flow, thereby reducing energy loss and noise, and improving the efficiency of the fan.

[0065] Specifically, in a projection plane perpendicular to the central axis of the centrifugal impeller 20, a circle C2 is made with the central axis of the bottom plate 22 as the center O and a line from the center to the outer end of the blade 21 as the radius. The circle C2 and the front end of the blade 21 form an intersection E2, and then a tangent F2 is made with the intersection E2 as the common intersection point. The angle between F2 and the blade 21 is the inlet installation angle a2 of the blade 21.

[0066] n is the number of blades 21. The number of blades 21 of the impeller is an important parameter directly related to the aerodynamic performance of the fan. The number of blades 21 and the cross-sectional shape of the centrifugal impeller 20 determine the cross-sectional area of ​​the airflow channel. When the number of blades 21 is too small, the airflow channel is too wide, which may cause secondary vortexes to form in the impeller channel, resulting in pressure loss; when the number of blades 21 is too large, the effective flow area of ​​the gas is reduced, which will cause the inlet impact loss and friction loss of the centrifugal impeller 20 to increase, and at the same time increase the load of the impeller main shaft, reducing the total pressure and efficiency of the fan.

[0067] In addition, the effective flow area of ​​the airflow channel can be improved by adjusting the hub ratio and the number of blades 21, and the outflow speed and smoothness of the airflow channel can be improved by adjusting the hub ratio and the number of blades 21, thereby improving the fan efficiency.

[0068] Experimental calculations have shown that when the centrifugal impeller 20 satisfies the following conditions: 0.65≤D2 / D1≤0.75, 39°≤a1≤51°, 51°≤a2≤71°, 8≤n≤12, the centrifugal impeller 20 can enable the airflow to enter and discharge the airflow channel between two adjacent blades 21 more smoothly, increase the flow velocity balance of the airflow at various locations in the channel between two adjacent blades 21, and thus enable the airflow to flow smoothly in the channel between two adjacent blades 21, thereby preventing energy waste caused by airflow turbulence and improving fan efficiency.

[0069] Among them, the hub ratio can be 0.65, 0.66, 0.67, 0.68, 0.7 or 0.75, the inlet installation angle can be 39°, 40°, 41°, 42°, 43°, 44°, 45°, 46°, 48°, 50° or 51°; the outlet installation angle can be 51°, 52°, 53°, 54°, 55°, 56°, 58°, 60°, 62°, 64°, 65°, 70° or 71°; the number of blades 21 can be 8, 9, 10, 11 or 12.

[0070] For example, when other conditions of the fan are constant, the centrifugal impeller 20 of the present application meets the above parameters, and three groups of the above parameters are randomly selected for simulation experiments, and the experimental data are shown in the following table:

[0071]

[0072]

[0073] It can be seen from the above table that when the hub ratio is 0.65, the inlet installation angle is 39°, the outlet installation angle is 51°, and the number of blades 21 is 8, the static pressure of the fan is increased by 19.58% relative to the static pressure of the existing fan, and the air volume is increased by 9.64% compared with the air volume of the existing fan; when the hub ratio is 0.70, the inlet installation angle is 45°, the outlet installation angle is 61°, and the number of blades 21 is 10, the static pressure of the fan is increased by 24.52% relative to the static pressure of the existing fan, and the air volume is increased by 13.25% compared with the air volume of the existing fan; when the hub ratio is 0.71, the inlet installation angle is 51°, the outlet installation angle is 71°, and the number of blades 21 is 12, the static pressure of the fan is increased by 18.76% relative to the static pressure of the existing fan, and the air volume is increased by 10.12% compared with the air volume of the existing fan. It can be seen that the fan static pressure and fan air volume show a trend of first increasing and then decreasing with the increase of parameters. Among them, the hub ratio is 0.70, the inlet installation angle is 45°, the outlet installation angle is 61°, and the number of blades 21 is 10, which are the optimal parameters. Under this condition, the static pressure increase and air volume increase are the highest.

[0074] According to the centrifugal impeller 20 of the embodiment of the present invention, by making the centrifugal impeller 20 satisfy the following conditions: 0.65≤D2 / D1≤0.75, 39°≤a1≤51°, 51°≤a2≤71°, 8≤n≤12, the airflow can enter and be discharged from the airflow channel between two adjacent blades 21 more smoothly, and the flow velocity balance of the airflow at various locations in the channel between two adjacent blades 21 is increased, so that the airflow can flow smoothly in the channel between two adjacent blades 21, thereby preventing energy waste caused by turbulence of the airflow and improving the efficiency of the fan.

[0075] In some specific embodiments, Figure 4 As shown, the centrifugal impeller 20 satisfies: 0.69≤D2 / D1≤0.71, 42°≤a1≤48°, 56°≤a2≤66°, 9≤n≤11. The fan static pressure increase and fan air volume increase of the centrifugal impeller 20 within this range are both better, and further, when the centrifugal impeller 20 satisfies: 0.69≤D2 / D1≤0.71, 42°≤a1≤48°, 56°≤a2≤66°, 9≤n≤11, the fan static pressure and fan air volume of the centrifugal fan using the centrifugal impeller 20 can be improved.

[0076] In some specific embodiments, Figure 3As shown, the bottom plate 22 has a mounting boss 221, the mounting boss 221 is circular, and a plurality of blades 21 are arranged on the radial outer side of the mounting boss 221 and are evenly spaced along the circumference of the mounting boss 221. Among them, the plurality of blades 21 are evenly spaced along the axial direction of the mounting boss 221, which can improve the balance of the centrifugal impeller 20, and thus improve the integrity of the centrifugal impeller 20. At the same time, the mounting boss 221 is used to be connected to the driving device, and the blades 21 are installed on the radial outer side of the mounting boss 221, and then the driving device can drive the plurality of blades 21 to rotate by driving the mounting boss 221 to rotate, so that the blades 21 can do work on the airflow and drive the airflow to move. In addition, the mounting boss 221 is circular, has a simple structure, and is easy to produce, thereby reducing the production cost of the centrifugal impeller 20.

[0077] For example Figure 3 As shown, the mounting boss 221 is formed by the base plate 22 being recessed from one side to the other side in the thickness direction, the recessed side is adapted to the driving device, and the mounting boss 221 is in surface contact with the driving device, thereby increasing the contact area with the driving device and improving the installation stability of the centrifugal impeller 20.

[0078] In some specific embodiments, Figure 3 As shown, the bottom plate 22 also has: a connecting plate portion 222, the connecting plate portion 222 is connected to the periphery of the mounting boss 221 and extends radially outward from the mounting boss 221, and a plurality of blades 21 are arranged on one side surface of the connecting plate portion 222. The connecting plate portion 222 is used to connect the blades 21 and the mounting boss 221, and the connecting plate portion 222 provides an installation space for the blades 21; at the same time, the plurality of blades 21 are arranged on one side surface of the connecting plate portion 222, and the plurality of blades 21 and the mounting boss 221 are arranged on the same side, which can facilitate the molding and installation of the centrifugal impeller 20.

[0079] In some specific embodiments, Figure 3 As shown, the connecting plate portion 222 includes a plurality of connecting pieces 2221, and the plurality of connecting pieces 2221 are arranged at intervals along the circumference of the mounting boss 221. The plurality of connecting pieces 2221 correspond to the plurality of blades 21 one by one, and the blades 21 are arranged on the corresponding connecting pieces 2221. For example, the plurality of connecting pieces 2221 may be two, three or more. Among them, two adjacent blades 21 and the connecting piece 2221 form an airflow channel, which can be used to limit the gas flow direction so that the airflow enters from the axial direction and flows out radially.

[0080] In some specific embodiments, Figure 3 As shown, the blade 21 is connected to one side edge of the connecting piece 2221 in the circumferential direction of the mounting boss 221 , which can improve the convenience of forming the blade 21 .

[0081] For example Figure 3As shown, one end of the blade 21 is connected to one side edge of the connecting piece 2221 , and the other end extends in a direction away from the connecting piece 2221 , and the blade 21 is vertically connected to the connecting piece 2221 .

[0082] In some specific embodiments, Figure 3 As shown, reinforcing ribs 223 are formed on the connecting piece 2221 , and the reinforcing ribs 223 can increase the structural strength of the connecting piece 2221 , thereby increasing the connection stability of the blade 21 .

[0083] For example Figure 3 As shown, the reinforcing rib 223 is a convex structure formed on the side surface of the connecting piece 2221 that is concave from the side surface away from the blade 21 toward the side surface close to the blade 21, and is simple in structure and easy to form, thereby reducing the production process of the blade 21 and reducing the production cost.

[0084] In some specific embodiments, Figure 3 As shown, one end of the reinforcing rib 223 is connected to the circumference of the mounting boss 221, and the other end of the reinforcing rib 223 extends along the extension direction of the blade 21, which can increase the structural strength of the entire connecting piece 2221, and further increase the supporting stability of the connecting piece 2221 to the blade 21; at the same time, the other end of the reinforcing rib 223 extends along the extension direction of the blade 21, and can also make the reinforcing rib 223 and the airflow flow in the same direction, thereby reducing the influence of the reinforcing rib 223 on the airflow direction.

[0085] Furthermore, for example Figure 3 As shown, the raised portion of the reinforcing rib 223 is arc-shaped, and the arc-shaped structure can reduce the influence of the reinforcing rib 223 on the airflow.

[0086] In some specific embodiments, Figure 3 As shown, the centrifugal impeller 20 is integrally formed by stamping. The integrally formed stamping has a simple structure and is easy to manufacture, thereby reducing the number of processing steps for the centrifugal impeller 20, increasing the processing speed of the centrifugal impeller 20, shortening the processing cycle, reducing material consumption, and reducing the production cost of the centrifugal impeller 20; at the same time, the integrally formed stamping can also reduce the number of installation steps for the centrifugal fan, thereby reducing the number of assembly processes for the centrifugal fan and shortening the assembly time.

[0087] The cooking device according to the third embodiment of the present invention comprises a cavity and a hot air assembly according to the second embodiment of the present invention, wherein the cavity has a cooking cavity, and the air outlet 112 is connected to the cooking cavity.

[0088] The cooking appliance according to the embodiment of the present invention is provided with the hot air assembly of the second embodiment, thereby improving the overall performance of the cooking appliance.

[0089] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0090] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0091] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0092] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0093] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A cover plate, the cover plate being arranged on one side of a centrifugal impeller in the axial direction, characterized in that: The cover plate has a first surface and a second surface which are arranged opposite to each other in the axial direction of the centrifugal impeller, the first surface is arranged toward the centrifugal impeller, an air inlet hole and an air outlet hole which pass through the cover plate are formed on the cover plate, at least a portion of the peripheral wall of the air outlet hole is formed as a first inclined surface which is inclined relative to the axis of the centrifugal impeller, and in the direction from the first surface toward the second surface, the inclination direction of the first inclined surface is the same as the inclination direction of the blades of the centrifugal impeller.

2. The cover plate according to claim 1, characterized in that: The angle between the first inclined surface and a plane perpendicular to the axis of the centrifugal impeller is 21°-35°.

3. The cover plate according to claim 1, characterized in that: A flange is provided on the periphery of the air outlet, and in a direction from the first surface toward the second surface, the flange extends obliquely outward along the radial direction of the centrifugal impeller.

4. The cover plate according to claim 1, characterized in that: In the radial direction from inside to outside of the centrifugal impeller, the air outlet hole is an arc-shaped hole extending obliquely along the circumference of the centrifugal impeller, and the inclination direction of the arc-shaped hole is the same as the inclination direction of the blades of the centrifugal impeller.

5. The cover plate according to claim 1, characterized in that: There are multiple air outlet holes, and the multiple air outlet holes are arranged at intervals around the centrifugal impeller.

6. The cover plate according to any one of claims 1 to 5, characterized in that: The ratio of the total flow cross-sectional area of ​​the air inlet holes to the total flow cross-sectional area of ​​the air outlet holes is 1.2-3.

5.

7. The cover plate according to any one of claims 1 to 5, characterized in that: There are multiple air inlet holes, and the multiple air inlet holes are arranged around the axis of the centrifugal impeller.

8. The cover plate according to claim 1, characterized in that The cover plate comprises: A bottom plate portion, the bottom plate portion is a plate body and is arranged perpendicular to the central axis of the centrifugal impeller, and the air outlet is formed on the bottom plate portion; A side plate portion, wherein the side plate portion extends in a ring shape along the circumference of the bottom plate portion, one end of the side plate portion is connected to the circumference of the bottom plate portion and the other end extends along the axial direction of the centrifugal impeller, and the side plate portion cooperates with the bottom plate portion to define a cavity for accommodating the centrifugal impeller; A side plate portion is connected to the other end of the side plate portion and extends outward away from the bottom plate portion in a plane perpendicular to the central axis of the centrifugal impeller, and a fixing hole for fixing the cover plate is formed on the side plate portion.

9. The cover plate according to claim 1, characterized in that: The cover plate is integrally formed.

10. A hot air component, characterized in that: include: A centrifugal impeller, a heating element and a cover plate according to any one of claims 1 to 9, wherein the centrifugal impeller is arranged on a side where the first surface of the cover plate is located, and the heating element is arranged around the centrifugal impeller.

11. A cooking utensil, characterized in that: It comprises a cavity and a hot air assembly according to claim 10, wherein the cavity has a cooking cavity, and the air outlet is connected to the cooking cavity.

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