JP2010007878A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heat the inside of a cooking chamber to a target temperature by a target time. <P>SOLUTION: A centrifugal turbo fan having a rear shroud plate 23 and a front shroud plate 26 is used as a hot air fan 20 for circulating hot air in the cooking chamber, and an oven heater is disposed while surrounding the hot air fan 20, thus the air is efficiently applied to the oven heater from the hot air fan 20. As heat exchanger effectiveness by the oven heater is increased, the inside of the cooking chamber can be heated to the target temperature by the target time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooking device having an oven cooking function for heating a food item with hot air.

Some of the heating cookers have a configuration in which a casing is fixed to the rear plate of the cooking chamber. This casing forms a space-like fan chamber between the rear plate of the cooking chamber, and a fan is accommodated in the fan chamber. This fan is connected to the rotating shaft of the fan motor. In the operating state of the fan motor, the air inside the cooking chamber is moved from the intake port on the rear plate of the cooking chamber to the inside of the casing based on the rotation of the fan. The air in the casing is sucked and discharged from the exhaust port on the rear plate of the cooking chamber into the cooking chamber. A heater is accommodated in the casing, and the heater is turned into hot air based on heating the air discharged from the fan inside the casing, and hot air for cooking the oven is circulated in the cooking chamber.
JP 2003-232521 A

  In the case of the heating cooker, a centrifugal fan is used as a fan. This centrifugal fan is formed by fixing a plurality of blade portions to the outer peripheral portion of the main plate portion, and each of the plurality of blade portions is inclined backward with respect to the rotation direction of the fan. With this conventional fan, it is difficult to efficiently blow air from the fan to the heater, and it is difficult to raise the temperature of the cooking chamber to the target temperature (for example, 350 ° C.) in the target time (for example, 30 minutes).

  This invention is made | formed in view of the said situation, and it aims at providing the heating cooker which can raise a cooking chamber to target temperature by target time.

  The cooking device according to the present invention has a cooking chamber having a front surface on the user's side that opens as an entrance / exit of a cooked product and a rear plate on the side opposite to the entrance / exit, and a closure that closes the entrance / exit of the cooking chamber. A space between the door that can be operated between the state and the open state that opens the entrance of the cooking chamber, and the rear plate of the cooking chamber that is provided outside the cooking chamber on the rear plate of the cooking chamber A casing forming a fan-shaped fan chamber, an intake port provided in front of the casing on a rear plate of the cooking chamber, for sucking air from the inside of the cooking chamber into the casing, and the cooking chamber A rear plate provided in front of the casing for exhausting air from the inside of the casing to the inside of the cooking chamber; and a predetermined state determined by the closed state of the door provided in the casing. One direction A centrifugal fan that draws air inside the cooking chamber from the intake port into the fan casing based on rotation, and discharges air inside the casing from the exhaust port to the inside of the cooking chamber. And a fan motor that rotates the fan in one direction, and the air that is provided inside the casing so as to surround the fan is heated into air based on heating inside the casing. An electric heater, wherein the fan is rotated in one direction by the fan motor, a plurality of blade portions provided on the main plate portion and inclined backward with respect to the rotation direction of the main plate portion, A rear shroud plate that covers each of the plurality of blade portions from the rear, and covers each of the plurality of blade portions from the front, and sucks air. Where having a front shroud plate annular having an opening and a feature.

  A centrifugal turbofan having both a rear shroud plate and a front shroud plate is used as a fan for circulating hot air inside the cooking chamber, and the heater is arranged so as to surround the fan. Can be sprayed efficiently without coming off. For this reason, since the heat exchange rate in a heater increases, the inside of a cooking chamber can be raised to target temperature by target time.

  The outer box 1 in FIG. 1 has a rectangular shape with an open front, and includes a left side plate, a right side plate, a bottom plate, a top plate, and a rear plate. As shown in FIG. 2, a rectangular inner box 2 having an open front is fixed inside the outer box 1. The inner box 2 has a left side plate, a right side plate, a bottom plate, a top plate, and a rear plate. The left side plate of the outer box 1 and the left side plate of the inner box 2 are opposed to each other with a gap in the left-right direction. The right side plate of the outer box 1 and the right side plate of the inner box 2 face each other with a gap in the left-right direction, and the bottom plate of the outer box 1 and the bottom plate of the inner box 2 face each other with a gap in the vertical direction, The top plate of the outer box 1 and the top plate of the inner box 2 face each other with a gap in the vertical direction, and the rear plate of the outer box 1 and the rear plate of the inner box 2 face each other with a gap in the front and rear direction. is doing. The inner box 2 is where food is taken in and out through the front surface of the inner box 2, and the inner space of the inner box 2 corresponds to a cooking chamber 3 for cooking the food, and the front surface of the inner box 2 is cooked. It corresponds to the entrance / exit 4 for taking in and out things.

  As shown in FIG. 1, a horizontally long rectangular door 5 is attached to the outer box 1 so as to be rotatable about a horizontal shaft 6 at the lower end. The door 5 has a window 7 and a window frame 8 surrounding the window 7. The door 5 has a closed state in which the entrance 4 of the cooking chamber 3 is closed from the front and an open state in which the entrance 4 of the cooking chamber 3 is opened. 6 is turned around. The window 7 of the door 5 is made of a transparent glass plate, and the inside of the cooking chamber 3 can be visually recognized from the front through the window 7 of the door 5 with the door 5 closed. A magnetron 9 is fixed in the gap between the rear plate of the outer box 1 and the rear plate of the inner box 2 as shown in FIG. The magnetron 9 oscillates microwaves when a drive power supply is applied, and the microwaves oscillated from the magnetron 9 are irradiated into the cooking chamber 3.

  Each of the left side plate of the inner box 2 and the right side plate of the inner box 2 is formed with an upper plate support 10 that protrudes into the cooking chamber 3 as shown in FIG. Each of these upper plate supports 10 is linearly directed in the front-rear direction and is disposed so as to face each other in the left-right direction. The upper plate support 10 on the left side plate of the inner box 2 removably supports the left end portion of the square plate 11 for cooking the oven. The upper plate support 10 on the right side plate of the inner box 2 is a square plate for oven cooking. 11 is detachably supported, and a dish to be oven-cooked is placed on a square dish 11 for oven cooking.

  Each of the left side plate of the inner box 2 and the right side plate of the inner box 2 is formed with a lower pan support 12 that protrudes into the cooking chamber 3 as shown in FIG. Each of the lower plate supports 12 is linearly directed in the front-rear direction, and is opposed to each other in the left-right direction at a lower position than the upper plate support 10. The lower plate support 12 on the left side plate of the inner box 2 removably supports the left end of the square plate 11 for oven cooking, and the lower plate support 12 on the right side plate of the inner box 2 is a square plate for oven cooking. 11 is detachably supported, and a square dish 11 for oven cooking is set in the cooking chamber 3 so as to be detachable in two steps in the vertical direction with a gap therebetween.

  As shown in FIG. 2, two grill pan supports 13 projecting into the cooking chamber 3 are formed on the left side plate of the inner box 2 and the right side plate of the inner box 2. Each of these four grill pan supports 13 is linearly oriented in the front-rear direction, and is disposed at a higher position than the upper pan support 10. Each of the grill plate supports 13 on the left side plate of the inner box 2 removably supports the left end of the square plate for cooking the grill, and each of the grill plate supports 13 on the right side plate of the inner box 2 is a grill. The right end of the cooking square plate is detachably supported. In the cooking chamber 3, a grill cooking square plate is set detachably above the upper square plate 11 for cooking the oven. Is done. In the cooking chamber 3, a grill heater is fixed on the ceiling plate of the inner box 2, and when the grill heater is operated in a state where a cooking pan 3 is set in the cooking chamber 3. The food on the square plate for grill cooking is heated and cooked based on the fact that radiant heat is irradiated from the grill heater to the food on the square plate for grill cooking.

  As shown in FIG. 2, a casing 14 is fixed to the rear plate of the inner box 2. The casing 14 has a vertical bottom plate 15 and a side plate 16 surrounding the bottom plate 15. The bottom plate 15 has a square shape, and the side plate 16 has a vertical width dimension and a horizontal width dimension from the rear to the front. Each has a square tube shape that grows larger. The casing 14 is housed in a gap between the rear plate of the outer box 1 and the rear plate of the inner box 2, and the front surface of the casing 14 is closed by the rear plate of the inner box 2. A space-like fan chamber 17 is formed between the rear plates.

  A fan motor 18 is fixed to the bottom plate 15 of the casing 14 as shown in FIG. The fan motor 18 is a capacitor induction motor and is disposed outside the casing 14. The fan motor 18 has a rotary shaft 19 oriented in the front-rear direction, and the front end of the rotary shaft 19 passes through the bottom plate 15 of the casing 14 and is inserted into the fan chamber 17. As shown in FIG. 4, a hot air fan 20 is connected to the front end portion of the rotating shaft 19 so as to be located in the fan chamber 17. The hot air fan 20 corresponds to a fan, and the fan motor 18 rotates the hot air fan 20 in the same direction based on the rotation in one predetermined direction. The hot air fan 20 is a centrifugal turbo fan, and the detailed configuration of the hot air fan 20 is as follows.

  As shown in FIG. 5, the main plate portion 21 is connected to the rotating shaft 19 of the fan motor 18 so as not to rotate. The main plate portion 21 is made of a metal plate perpendicular to the rear plate of the inner box 2 and the bottom plate 15 of the fan casing 14, and eight rear shroud plate joint portions 22 are provided on the outer peripheral portion of the main plate portion 21. Is formed. Each of these eight rear shroud plate joining portions 22 refers to a triangular portion projecting outward from the main plate portion 21, and has a circumference on a common circular locus centering on the center point CP 1 of the main plate portion 21. They are arranged at equal pitches in the direction. As shown in FIG. 6, a rear shroud plate 23 is joined to each of the eight rear shroud plate joint portions 22. The rear shroud plate 23 is formed of an annular metal plate that closes the gap between the rear shroud plate joint portions 22 adjacent in the circumferential direction from the rear, and the main plate portion 21 has an opening of the rear shroud plate 23. Closed from the front.

  As shown in FIG. 7, each of the eight rear shroud plate joining portions 22 is formed with a wing portion 24, and each of the eight wing portions 24 is centered on the center point CP <b> 1 of the main plate portion 21. Are arranged at equal pitches in the circumferential direction on a common circular locus. Each of the eight blade portions 24 has a plate shape that protrudes vertically forward from the rear shroud plate joint portion 22 and has the same inclination angle θ in the rearward direction with respect to the rotational direction of the hot air fan 20. Inclined. As shown in FIG. 5, the inclination angle θ refers to an angle at which the blade portion 24 is inclined backward with respect to a straight line connecting the center point CP1 of the main plate portion 21 and the tips of the blade portions 24. 30 ° ".

  As shown in FIG. 7, a front shroud plate joint portion 25 is formed at the front end portion of each of the eight blade portions 24. Each of the eight front shroud plate joint portions 25 has a plate shape perpendicular to the blade portion 24, and a common front shroud plate 26 is joined to each of the eight front shroud plate joint portions 25. Has been. The front shroud plate 26 is made of an annular metal plate that closes the gap between the blade portions 24 adjacent in the circumferential direction from the front. The front shroud plate 26 is concentric with the rear shroud plate 23. The outer diameter of the front shroud plate 26 and the outer diameter of the rear shroud plate 23 are set to the same value. The ratio between the inner diameter D1 and the outer diameter D2 of the front shroud plate 26 is set to “D1 / D2 = 0.6” as shown in FIG. The opening of the front shroud plate 26 functions as a suction port 27 for sucking air. When the upper plate 11 is set on the upper plate supports 10 of the inner box 2, the upper plate 11 is used. Faces the upper end of the suction port 27 from the front.

  FIG. 9 shows the relationship between the inner / outer diameter ratio “D1 / D2” of the front shroud plate 26 and the flow coefficient, and the flow coefficient of the hot air fan 20 is determined by the inner / outer diameter ratio “D1 / D2” of the front shroud plate 26. Increasing as one approaches "1". That is, it is advantageous that the width of the front shroud plate 26 is narrow in order to increase the amount of air discharged from the hot air fan 20. The front shroud plate 26 connects the blade portions 24 to each other. To increase the mechanical strength of the hot air fan 20, it is advantageous that the width of the front shroud plate 26 is large. The inner / outer diameter ratio “D1 / D2” of the front shroud plate 26 is set to “0.6” in consideration of both the air volume and the mechanical strength of the hot air fan 20. The hot air fan 20 is configured as described above.

  As shown in FIG. 4, an oven heater 28 made of a sheathed heater is fixed in the casing 14. The oven heater 28 has a rectangular frame shape surrounding the hot air fan 20, and has a horizontal upper side, a horizontal lower side, a vertical left side, and a vertical right side. As shown in FIG. 10, the oven heater 28 is formed by housing a nichrome wire 30 in a metal heat radiating pipe 29. As shown in FIG. 11, the heat radiating pipe 29 has eight axial centers. The blade portions 24 are arranged so as to be positioned on the center line CL1 in the front-rear direction. The outer diameter R1 (for example, 8 mm) of the heat radiating pipe 29 is set smaller than the width dimension W1 (for example, 11 mm) in the front-rear direction of the blade portion 24 of the hot air fan 20, and the heat radiating pipe 29 has eight blade portions. The radial direction of the hot air fan 20 in each of the eight blade portions 24 without making a business trip forward compared with the respective front end surfaces of the eight blade portions 24 without making a business trip backward compared with the rear end surfaces of the respective 24 Are arranged opposite each other. The heat radiating pipe 29 is blown by a straight component that travels without tilting forward or backward among the winds discharged from each of the eight blade portions 24, and is discharged from the hot air fan 20. The linear component of the wind is hot-aired based on being blown to the heat radiating pipe 29 of the oven heater 28. The oven heater 28 corresponds to a heater.

  As shown in FIG. 10, heat radiation fins 31 are fixed to the oven heater 28 on the outer peripheral surface of the heat radiation pipe 29. The heat dissipating fin 31 is configured by winding a metal plate of the same type as the heat dissipating pipe 31 around the outer peripheral surface of the heat dissipating pipe 29 in a spiral shape, and has a plurality of heat dissipating portions 32. Each of the plurality of heat radiating portions 32 is arranged at intervals along the heat radiating pipe 29 and has an annular shape along the direction of air flow discharged by the hot air fan 20. Each of the plurality of heat radiating portions 32 has a function of expanding the heat generating area of the heat radiating pipe 29 by being heated through the heat radiating pipe 29. As shown in FIG. 11, the outer diameter R <b> 2 of each of the plurality of heat radiating portions 32 is set to be larger than the width dimension W <b> 1 of the blade portion 24. Compared to the rear end surface, the bulge protrudes backward, and travels forward compared to the front end surface of the blade 24. Each of the plurality of heat radiating portions 32 is one to which a slope component that advances and inclines backward and forward is blown out of the wind discharged from the blade portion 24, and the inclination of the wind discharged from the blade portion 24. The component is hot-aired based on being sprayed on the radiation fin 31.

  As shown in FIG. 10, a gap is formed between the outer peripheral surface of the hot air fan 20 and the outer peripheral surface of the radiating fin 31 so as to be located in the entire circumferential direction of the hot air fan 20. The outer peripheral surface of the hot air fan 20 refers to the maximum outer diameter of the hot air fan 20 (= the outer peripheral surface of the rear shroud plate 23 and the outer peripheral surface of the front shroud plate 26). The clearance C1 between the outer peripheral surfaces of the fins 31 is set larger than the minimum value of “2 mm”. The radiating fins 31 have an effect on increasing the static pressure of the hot air fan 20. The static pressure of the hot air fan 20 is the pressure when the hot air fan 20 sends air against resistance (pressure loss). Called. FIG. 12 shows the relationship between the air volume and the static pressure of the hot air fan 20 at a plurality of different inclination angles θ. This air volume is the volume of air that the hot air fan 20 discharges per unit time, and the air volume of the hot air fan 20 becomes higher when the static pressure is lower regardless of the inclination angle θ. That is, in order to increase the air volume of the hot air fan 20, it is preferable that the gap dimension C <b> 1 between the outer peripheral surface of the hot air fan 20 and the outer peripheral surface of the radiating fin 31 is large.

  The heat radiating pipe 29 expands with heat when the oven heater 28 is operated, and the heat radiating fins 31 approach the outer peripheral surface of the hot air fan 20 as the heat radiating pipe 29 expands. For this reason, in order to avoid contact between the outer peripheral surface of the hot air fan 20 and the outer peripheral surface of the radiating fin 31 due to expansion of the radiating pipe 29, it is preferable that the gap dimension C1 is large. The radiating fin 31 heats the inclined component of the wind discharged from the hot air fan 20, and it is preferable that the gap dimension C1 is small in that the inclined component is brought into contact with the radiating fin 31 without escaping. That is, the minimum value “2 mm” of the gap dimension C1 is that the air volume of the hot air fan 20 is increased, the heat fin 31 is prevented from coming into contact with the hot air fan 20, and the slope component of the wind discharged by the hot air fan 20 is used. It is set in consideration of three points to be efficiently contacted with each other.

  As shown in FIG. 3, a circular protrusion 33 is formed on the rear plate of the inner box 2 so as to be positioned in front of the suction port 27 of the hot air fan 20. The protrusion 33 projects forward relative to the remaining portion of the rear plate of the inner box 2 except for the protrusion 33, and the diameter dimension of the protrusion 33 is the same value as the inner diameter dimension D1 of the front shroud plate 26. Is set to The rear plate of the inner box 2 is formed with a hot air inlet 34 composed of a plurality of through holes. The hot air intake port 34 corresponds to an intake port. When the fan motor 18 is operated with the door 5 closed, the air in the cooking chamber 3 flows from the hot air intake port 34 to the intake port of the hot air fan 20. 27 is sucked in. The hot air intake port 34 includes an inner intake portion 35 and an outer intake portion 36. The inner intake portion 35 refers to a portion located inside the inner contour line IL, and the outer intake portion 36 has an outer contour line OL and an inner contour portion IL. The part located between outline IL is called. The outer contour line OL is a virtual line obtained by projecting the outer peripheral surface of the front shroud plate 26 onto the rear plate of the cooking chamber 3, and the inner contour line IL projects the inner peripheral surface of the front shroud plate 26 onto the rear plate of the cooking chamber 3. It is a virtual line. This inner contour line IL coincides with the outer peripheral surface of the projection 33, and the inner intake portion 35 is formed in a portion of the projection 33 that does not face the upper cooking pan 11 for cooking from the rear side. The total area of the portion 35 and the outside intake portion 36 is set to the same value as the area of the suction port 27 of the hot air fan 20.

  As shown in FIG. 4, a decoration member 37 is fixed to the main plate portion 21 of the hot air fan 20. The decorative member 37 is disposed so as to face the inner intake portion 35 of the hot air intake port 34 from the rear, and the decorative member 37 has a width dimension in the front-rear direction so that the decorative member 37 travels forward from the front surface of the front shroud plate 26. The size is set. That is, the protrusion 33 on the rear plate of the cooking chamber 3 is for avoiding the decorative member 37 coming into contact with the rear plate of the cooking chamber 3.

  The decorative member 37 is visually recognizable from the front through the inner air intake 35 of the hot air inlet 34 when the user opens the door 5 while the hot air fan 20 is stationary, and is a circle concentric with the hot air fan 20. It is composed of a plate-like metal. An uneven pattern is formed on the front surface of the decorative member 37. This pattern imitates the backward-facing blade portion that inclines in the same direction as each of the eight blade portions 24 of the hot-air fan 20, and has a function of enhancing the visual recognition in the stationary state of the decorative member 37. ing.

  As shown in FIG. 3, a plurality of upper hot air exhaust ports 38 are formed in the rear plate of the inner box 2. Each of the plurality of upper hot air exhaust ports 38 refers to an aggregate of through holes, and is opposed to both the heat radiating pipe 29 and the heat radiating fins 31 of the oven heater 28 from the front. Each of the plurality of upper hot air outlets 38 is disposed higher than the upper square plate 11 for cooking the oven, and a plurality of hot airs generated in the casing 14 by both the heat radiating pipe 29 and the heat radiating fins 31 are provided. The air is exhausted forward from each of the upper hot air exhaust ports 38, proceeds upward from behind the upper square plate 11 for cooking the oven, and hits the door 5. The hot air travels from the front to the rear through the gap between the upper and lower square plates 11 for cooking the oven, and is sucked into the suction port 27 of the hot air fan 20 from the hot air intake port 34. Each of the plurality of upper hot air exhaust ports 38 corresponds to an exhaust port.

  As shown in FIG. 3, a plurality of lower hot air exhaust ports 39 are formed in the rear plate of the inner box 2. Each of the plurality of lower hot air exhaust ports 39 refers to an aggregate of through holes, and is opposed to both the heat radiating pipe 29 and the heat radiating fins 31 of the oven heater 28 from the front. Each of the plurality of lower hot air exhaust ports 39 is disposed at a lower position than the lower square plate 11 for oven cooking, and a plurality of hot airs generated in the casing 14 by both the heat radiating pipe 29 and the heat radiating fins 31 are generated. The air is exhausted forward from each of the lower hot air exhaust ports 39, proceeds downward from the lower square plate 11 for cooking the oven to the front, and hits the door 5. The hot air travels from the front to the rear through the gap between the upper and lower square plates 11 for cooking the oven, and is sucked into the suction port 27 of the hot air fan 20 from the hot air intake port 34. Each of the plurality of lower hot air exhaust ports 39 corresponds to an exhaust port.

  As shown in FIG. 3, a left hot air exhaust port 40 and a right hot air exhaust port 41 are formed in the rear plate of the inner box 2. Each of the left hot air exhaust port 40 and the right hot air exhaust port 41 refers to an aggregate of through holes, and is opposed to both the heat radiating pipe 29 and the heat radiating fin 31 from the front. Each of the left hot air exhaust port 40 and the right hot air exhaust port 41 is disposed at a height between the upper and lower square plates 11 and 11 for cooking the oven. The hot air generated in the casing 14 is exhausted forward from each of the left hot air exhaust port 40 and the right hot air exhaust port 41, and a gap is formed between the upper and lower square plates 11 for cooking the oven. Proceed from back to front and hit door 5. The hot air travels from the front to the rear through the gap between the upper and lower square plates 11 for cooking the oven, and is sucked into the suction port 27 of the hot air fan 20 from the hot air intake port 34. Each of the left hot air exhaust port 40 and the right hot air exhaust port 41 corresponds to an exhaust port.

  A control circuit mainly composed of a microcomputer is accommodated in a gap between the rear plate of the outer box 1 and the rear plate of the inner box 2. This control circuit has a CPU, a ROM, and a RAM, and a rotary encoder is connected to the control circuit. This rotary encoder has a rotating shaft oriented in the front-rear direction, and a dial 42 is mechanically connected to the rotating shaft of the rotary encoder. As shown in FIG. 1, the dial 42 is disposed on the window frame 8 of the door 5 so as to be operable from the front. The rotary encoder rotates the dial 42 based on the rotation of the dial 42. The number of pulse signals corresponding to is output to the control circuit. A plurality of cooking menus are recorded in advance in the ROM of the control circuit, and when the control circuit determines that a pulse signal has been output from the rotary encoder, one corresponding to the number of output pulse signals is selected from the plurality of cooking menus. select. That is, the dial 42 is for selecting a cooking menu.

  A liquid crystal display 43 is connected to the control circuit. As shown in FIG. 1, the liquid surface indicator 43 is fixed to the window frame 8 of the door 5 so as to be visually recognizable from the front, and the control circuit displays a liquid crystal display when the cooking menu is selected. The selection result of the cooking menu is displayed on the vessel 43. A start switch composed of a push switch is connected to the control circuit, and a start key 44 is mechanically connected to an operation element of the start switch. The start key 44 is attached to the window frame 8 of the door 5 so as to be operable from the front, and the electrical state of the start switch is switched based on the operation of the start key 44.

  A magnetron, a grill heater, a fan motor 18 and an oven heater 28 are connected to the control circuit. When the control circuit determines that the electrical state of the start switch has been switched, the magnetron, the grill heater and the fan motor 18 are connected. Of the oven heaters 28, the one corresponding to the selection result of the cooking menu is operated with the content corresponding to the selection result of the cooking menu. Hereinafter, the processing content of the control circuit when the cooking menu “hamburger” is selected will be described.

  The control circuit circulates hot air in the cooking chamber 3 based on the start of operation of each of the fan motor 18 and the oven heater 28. The fan motor 18 is continuously operated at a constant medium speed within an initial heating period from the start of operation until a predetermined time elapses, and a predetermined time elapses after the initial heating period ends. In the middle heating period until the middle heating period, it is continuously operated at a constant low speed that is slower than the middle speed, and in the final heating period until a predetermined time elapses after the middle heating period ends. The oven heater 28 is continuously operated at a constant high speed that is faster than the medium speed, and the oven heater 28 is continuously operated so as to have a predetermined output from the start of operation until the end of the final heating period. Is done.

  FIG. 13 shows the temporal change in the internal temperature when the cooking menu “hamburger” is selected. This internal temperature is the temperature in the cooking chamber 3, the internal temperature increases at a medium temperature change rate during the initial heating period, and the internal temperature is a low temperature change that is smaller than the intermediate temperature change rate during the intermediate heating period. In the final heating period, the internal temperature rises at a high temperature change rate higher than the medium temperature change rate. This intermediate heating period is a period for storing heat in the casing 14, and in the final heating period, the heat stored in the casing 14 during the intermediate heating period is released into the cooking chamber 3 at once. The temperature rises rapidly and the target value “350 ° C.” is reached reliably.

According to the said Example 1, there exists the following effect.
Since the centrifugal turbo fan having each of the rear shroud plate 23 and the front shroud plate 26 is used as the hot air fan 20 and the oven heater 28 is disposed so as to surround the hot air fan 20, the hot air fan 20 is changed to the oven heater 28. It is blown efficiently without the wind coming off. For this reason, since the heat exchange rate in the oven heater 28 increases, the inside of the cooking chamber 3 can be raised to the target temperature (for example, 350 ° C.) in the target time (for example, 30 minutes). The inner / outer diameter ratio of the front shroud plate 26 was set to “0.6”. For this reason, since the air flow in the hot air fan 20 is improved, the quietness is improved. Since the hot air intake port 34 is constituted by the inner intake portion 35 and the outer intake portion 36, the amount of intake air of the hot air fan 20 is affected by the effect that the upper square plate 11 for cooking the oven overlaps a part of the intake port 27 of the hot air fan 20. Decrease is suppressed.

  The outer diameter R1 of the heat radiating pipe 29 was set smaller than the width dimension W1 in the front-rear direction of the blade portion 24, and the heat radiating pipe 29 was arranged so as not to travel from the rear end surface and the front end surface of the blade portion 24. For this reason, since the linear component of the wind discharged by the hot air fan 20 is blown to the heat radiating pipe 29 without being detached, heat is efficiently exchanged by the heat radiating pipe 29. The outer diameter R2 of the radiating fin 31 is set larger than the width dimension W1 in the front-rear direction of the blade 24, and the radiating fin 31 is disposed so as to make a business trip from each of the rear end surface and the front end surface of the blade 24. For this reason, since the inclination component of the wind discharged from the hot air fan 20 is blown to the radiating fins 31, heat exchange is efficiently performed by the radiating fins 31.

  Since the heat radiating fins 31 are composed of a plurality of heat radiating portions 32 along the direction of the air flow discharged from the hot air fan 20, it is possible to suppress a reduction in the air volume of the hot air fan 20 due to the effect of joining the heat radiating fins 31 to the heat radiating pipe 29. It is done. Since the decoration member 37 is provided on the main plate portion 21 and the user opens the door 5 while the hot air fan 20 is stationary, the presence of the hot air fan 20 can be visually confirmed from the front through the hot air inlet 34. The decorativeness in the cooking chamber 3 when the door 5 is opened while the hot air fan 20 is stationary is enhanced. In addition, since the user can directly recognize the presence of the rotating body behind the hot air intake port 34 with his / her own eyes, it is possible to prevent the act of inserting a foreign object into the hot air intake port 34.

  In the first embodiment, a double-suction turbo fan may be used as the hot air fan 20. In the case of this configuration, an opening corresponding to the opening of the rear shroud plate 23 may be formed in the main plate 21 of the hot air fan 20.

In the first embodiment, the inner / outer diameter ratio “D1 / D2” of the front shroud plate 26 is set to a value different from “0.6” within the range of “0.5” to “0.7”. Also good.
In the first embodiment, the inclination angle θ of the blade portion 24 may be set to a value different from “30 °” within the range of “10 °” to “90 °”.

  In the first embodiment, the ratio “R1 / W1” between the width dimension W1 in the front-rear direction of the blade portion 24 and the outer diameter dimension R1 of the heat radiating pipe 29 is “8/11” out of the values larger than “0.7”. It may be set to a value different from “”.

In the first embodiment, the minimum gap dimension C1 between the outer peripheral surface of the hot air fan 20 and the radiating fins 31 may be set to a value different from “2 mm” among the values of “2 mm” or more.
In the first embodiment, the number of the blade portions 24 may be set to a number different from “8” out of “6” or more and “12” or less.

  In the said Example 1, you may apply this invention to the heating cooker only for oven cooking.

The figure which shows Example 1 (The figure which shows the external appearance of a microwave oven from the front) Sectional view along line X2 in FIG. The figure which shows the internal structure of a cooking chamber from the front in the removal state of a door The figure which shows the internal structure of a casing from the front The figure which shows the main board part of a hot-air fan from the front Perspective view showing appearance of hot air fan A perspective view showing the appearance of the hot air fan in an exploded state Figure showing the front shroud plate from the front Diagram showing the correlation between the inner / outer diameter ratio of the front shroud plate and the flow coefficient of the hot air fan (A) The figure which shows a hot air fan and an oven heater from the front, (b) is Xb view. Diagram showing the positional relationship between the hot air fan and the oven heater A diagram showing the correlation between air volume and static pressure of a hot air fan The figure which shows the time change of the inside temperature

Explanation of symbols

  3 is a cooking chamber, 4 is an entrance, 5 is a door, 14 is a casing, 17 is a fan chamber, 18 is a fan motor, 20 is a hot air fan (fan), 21 is a main plate portion, 23 is a rear shroud plate, and 24 is a blade portion. , 26 is a front shroud plate, 27 is a suction port (opening), 28 is an oven heater (heater), 29 is a heat radiating pipe, 30 is a nichrome wire, 31 is a heat radiating fin, 32 is a heat radiating portion, 34 is a hot air inlet ( (Intake port), 35 is an inner intake portion, 36 is an outer intake portion, 37 is a decorative member, 38 is an upper hot air exhaust port (exhaust port), 39 is a lower hot air exhaust port (exhaust port), and 40 is a left hot air exhaust port ( Reference numeral 41 denotes a right hot air exhaust port (exhaust port).

Claims (7)

The front side, which is the user side, opens as an entrance to the cooked food, and a cooking chamber having a rear plate on the opposite side to the entrance,
A door operable between a closed state for closing the entrance of the cooking chamber and an open state for opening the entrance of the cooking chamber;
A casing that is provided outside the cooking chamber on the rear plate of the cooking chamber, and that forms a spatial fan chamber with the rear plate of the cooking chamber;
An air inlet provided on the rear plate of the cooking chamber located in front of the casing, for sucking air from the inside of the cooking chamber into the casing;
An exhaust port provided on the rear plate of the cooking chamber located in front of the casing, for exhausting air from the casing to the cooking chamber;
The casing is provided inside the casing, and sucks air inside the cooking chamber from the inlet to the inside of the fan casing based on rotation in a predetermined direction with the door closed. A centrifugal fan that exhausts the air inside the cooking chamber through the exhaust port,
A fan motor for rotating the fan in one direction;
An electric heater that is provided inside the casing so as to surround the fan and that heats the air discharged from the fan by heating inside the casing;
The fan is
A main plate that is rotated in one direction by the fan motor;
A plurality of blade portions provided in the main plate portion and inclined backward with respect to the rotation direction of the main plate portion;
A rear shroud plate covering each of the plurality of blade portions from the rear;
A heating cooker that covers each of the plurality of blades from the front and has an annular front shroud plate having an opening for sucking air.   The cooking device according to claim 1, wherein the front shroud plate has an "inner diameter dimension / outer diameter dimension" set to a value within a range of 0.5 to 0.7.   The intake port includes an inner intake portion located inside an inner contour line formed by projecting an inner peripheral surface of the front shroud plate onto a rear plate of the cooking chamber, and an outer peripheral surface of the front shroud plate. The heating cooker according to any one of claims 1 to 2, wherein the cooking device comprises an outer air intake portion that is positioned between the outer contour line and the inner contour line that are projected onto the rear plate. The heater is a sheathed heater having a heat radiating pipe facing each of the plurality of blade portions from the radial direction of the fan and a nichrome wire inserted into the heat radiating pipe,
The heat dissipating pipe has an outer diameter dimension set smaller than a width dimension in the front-rear direction of each of the plurality of blade portions, and does not travel backward from the rear end surface of each of the plurality of blade portions. The cooking device according to any one of claims 1 to 3, wherein the cooking device does not make a business trip forward from a front end face of each of the plurality of blade portions. The heater is provided with radiating fins protruding from the outer peripheral surface of the radiating pipe,
The radiating fin has an outer diameter dimension set larger than a width dimension of each of the plurality of blade portions in the front-rear direction, and travels backward from the rear end surface of each of the plurality of blade portions. The cooking device according to claim 4, wherein the cooking device is a business trip forward from the front end face of each of the plurality of blade portions.   The cooking device according to claim 5, wherein the heat dissipating fins include a plurality of heat dissipating portions along a flow direction of air discharged from the fan. The main plate portion is provided behind the intake port, and includes a decorative member that rotates together with the main plate portion in an operating state of the fan motor.
The said air inlet is comprised from the several through-hole which can recognize the said decoration member visually from the front when the said door is open | released in the stationary state of the said fan. The cooking device according to any one of 6.

Images