Cooker

Abstract

To provide a cooker capable of achieving energy saving by changing a power value to be applied to driving means for energizing a valve plate according to the temperature in an inner pot.SOLUTION: A cooker 10 includes: an inner pot; a cooker body 20 that stores the inner pot and includes heating means for heating the inner pot; a lid body 30 for closing the cooker body; an inner lid 40 mounted on the lid body for closing the inner pot; a pressure adjusting mechanism 50 of the inner pot; temperature detection means for measuring the temperature of the inside of the inner pot; and control means. The control means brings a supply power value to driving means into zero when a detection temperature of the temperature detection means is lower than a first temperature threshold, brings the supply power value into a first supply power value when the detection temperature is the first temperature threshold or higher and is lower than a second temperature threshold, which is higher than the first temperature threshold, and brings the supply power value into a second supply power value larger than the first supply power value when the detection temperature is the second temperature threshold or higher.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to pressure control in a cooking device such as a rice cooker that cooks food under pressure. [Background technology]

[0002] In a cooking appliance such as a rice cooker, an inner pot containing ingredients is placed inside the cooking appliance body, closed with a lid, and heated. During this heating, for example, in Patent Documents 1 and 2, a pressure valve mechanism is provided that keeps the inside of the inner pot airtight with a pressure valve, and cooking is performed under pressure, i.e., pressure cooking.

[0003] The pressure valve mechanism in Patent Documents 1 and 2 is composed of a pressure adjustment ball that closes the pressure adjustment hole formed in the inner lid, and a plunger that pushes the pressure adjustment ball out of the pressure adjustment hole. When pressurized, the pressure valve mechanism closes the pressure adjustment hole with the pressure adjustment ball, and when pressure is released, the plunger pushes the pressure adjustment ball out of the pressure adjustment hole, opening the pressure adjustment hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-81501 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-193946 Summary of the Invention [Problem to be solved by the invention]

[0005] A pressure valve that uses a pressure adjustment ball can only be switched between open and closed, and cannot adjust the set pressure inside the inner pot.

[0006] On the other hand, the applicant has proposed in Patent Application No. 2022-118031 a pressure valve mechanism in which a valve body that opens and closes a pressure adjustment hole is moved up and down by a solenoid placed above the valve body.

[0007] When the solenoid is energized, the movable part protrudes, pressing the valve body against the pressure adjustment hole and sealing the inner pot airtight. On the other hand, when the solenoid is de-energized, the movable part retracts, separating the valve body from the pressure adjustment hole and releasing the airtight state.

[0008] This type of pressure valve mechanism maintains a constant pressure regardless of the pressure inside the inner pot. Specifically, when the food inside the inner pot is brought to a boil, if the temperature of the steam sensor exceeds a predetermined value, the solenoid is activated at a power level corresponding to a predetermined rated pressure (see Figure 13).

[0009] In other words, whether the actual pressure inside the inner pot is lower than the rated pressure or close to the rated pressure, the pressure valve mechanism consumes the same amount of power in the solenoid, resulting in wasteful power consumption. Furthermore, if the solenoid continues to be used at the rated pressure, it will generate heat and its resistance will increase. This will further increase the solenoid's power consumption in order to maintain the rated pressure, shortening its lifespan.

[0010] The object of the present invention is to provide a heating cooker that can optimize the pressure inside the inner pot and save energy by changing the power value applied to the driving means that energizes the valve plate depending on the temperature inside the inner pot. [Means for solving the problem]

[0011] The cooking device of the present invention comprises: The inner pot and a cooking appliance body that houses the inner pot and includes a heating means for heating the inner pot; a lid that closes the cooking appliance body; An inner lid attached to the lid body and covering the inner pot, the inner lid having a pressure adjustment hole therethrough; a pressure adjustment mechanism including a valve body that opens and closes the pressure adjustment hole, and a driving means that urges the valve body toward the pressure adjustment hole, the driving means having a set pressure that urges the valve body variable in accordance with a supplied power value; a temperature detection means capable of measuring the temperature inside the inner pot; a control means; A cooking device having The control means sets the supply power value to the driving means to zero when the detected temperature of the temperature detection means is lower than a first temperature threshold, sets the supply power value to a first supply power value when the detected temperature is equal to or higher than the first temperature threshold and lower than a second temperature threshold that is higher than the first temperature threshold, and sets the supply power value to a second supply power value that is higher than the first supply power value when the detected temperature is equal to or higher than the second temperature threshold.

[0012] The control means has a plurality of temperature thresholds set between the first temperature threshold and the second temperature threshold, and can set the supply power value for each of the temperature thresholds.

[0013] The control means sets the plurality of temperature thresholds at equal intervals between the first temperature threshold and the second temperature threshold, and can change the supply power value proportionally to each temperature threshold.

[0014] The control means can reduce the value of the power supply to the drive means when the detected temperature is lower than the second temperature threshold for a certain period of time.

[0015] The temperature detection means is a steam sensor that detects the temperature of steam in the inner pot. [Effects of the Invention]

[0016] In the cooking device of the present invention, when the temperature inside the inner pot is low, the pressure inside the inner pot is also low, so energy can be saved by reducing the power consumption of the pressure adjustment mechanism and heat generation by the driving means can be suppressed. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a rice cooker according to one embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the rice cooker with the lid open, showing the state in which the inner lid is attached to the lid. [Figure 3]FIG. 3 is a front view of the rice cooker with the lid open and the inner lid removed from the lid. [Figure 4] FIG. 4 is an exploded view of the inner lid. [Figure 5] FIG. 5 is a vertical cross-sectional view of the cover, showing the state in which the valve body opens the pressure adjustment hole. [Figure 6] FIG. 6 is an enlarged view of the pressure adjustment mechanism, showing the state in which the valve body opens the pressure adjustment hole. [Figure 7] FIG. 7 is (a) a side view, (b) a cross-sectional view, and (c) a perspective view of the packing member in a state in which the valve body opens the pressure adjustment hole. [Figure 8] FIG. 8 is a vertical cross-sectional view of the cover, showing the state in which the valve body closes the pressure adjustment hole. [Figure 9] FIG. 9 is an enlarged view of the pressure adjustment mechanism, showing the state in which the valve body closes the pressure adjustment hole. [Figure 10] FIG. 10 is (a) a side view, (b) a cross-sectional view, and (c) a perspective view of the packing member in a state in which the valve body closes the pressure adjustment hole. [Figure 11] FIG. 11 is a block diagram of the control system for the solenoid. [Figure 12] FIG. 12 is a graph showing the correlation between the temperature detected by the steam sensor, the current value supplied to the solenoid, and the cumulative power consumption in the rice cooker of the invention example. [Figure 13] FIG. 13 is a graph showing the correlation between the temperature of the steam sensor, the value of the current supplied to the solenoid, and the integrated power consumption in the rice cooker of the comparative example. [Figure 14] FIG. 14 shows the graphs of FIGS. 12 and 13 superimposed on each other. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention relates to a cooking device that can reduce power consumption of a pressure adjustment mechanism 50 that closes a pressure adjustment hole 45 provided in an inner lid 40 according to the temperature inside the inner pot when cooking food that requires pressure application during heating. Below, an embodiment in which the cooking device of the present invention is applied to a rice cooker 10 will be described, but the cooking device may also be a pressure cooker, waterless pot, electric kettle, soup jar, multi-cooker, electric kettle, etc.

[0019] First, the configuration of a rice cooker 10 according to one embodiment of the present invention will be described, followed by a description of a cooking program including pressure control of the present invention. Figure 1 is a perspective view of rice cooker 10, and Figures 2 and 3 are perspective views showing the rice cooker with the lid open. Rice cooker 10 comprises a cooking device main body 20 that houses an inner pot (not shown) into which ingredients are placed, and a lid 30 that covers cooking device main body 20.

[0020] Cooking device main body 20 is equipped with a heater (not shown) such as a work coil as heating means, located opposite the side and bottom of the inner pot, allowing it to heat the inner pot. Cooking device main body 20 is also equipped with a temperature sensor as temperature detection means for measuring the temperature of the bottom of the pot. Based on the operation of operation switch 31, the control means (microcomputer) controls, for example, the heater and adjusts the amount of power supplied to solenoid 60 of pressure adjustment mechanism 50 in accordance with a program pre-stored in the control means, thereby performing cooking functions such as rice cooking and keeping food warm.

[0021] The inner pot can be a metal pot or earthenware pot of the general type used in rice cooker 10, and contains ingredients (rice, water, etc. in the case of rice cooker 10). An outward flange is formed on the upper edge of the inner pot, which comes into airtight contact with inner lid gasket 42 of lid body 30 shown in Figure 2.

[0022] As shown in FIG. 1, the top surface of the lid 30 is provided with an operation switch 31 for operating the rice cooker 10, a display 32 that shows the cooking state (in the case of the rice cooker 10, cooking, keeping warm, etc.), operation details, time, etc., and an exhaust hole 37 for discharging steam from the inner pot. Hereinafter, the side with the operation switch 31 will be referred to as the "front" where appropriate. The rear end of the lid 30 can be hingedly connected to the cooker body 20 so that it can be opened and closed, and it covers the inner pot when the inner lid 40 (FIG. 2) is attached. The lid 30 is constantly biased in the opening direction relative to the cooker body 20. The lid 30 opens when the opening / closing lever 21 on the cooker body 20 is operated, and it remains closed when the lid 30 is pressed in the closing direction.

[0023] As shown in Figures 2, 4, 5, etc., an inner lid 40 is attached to the underside of the lid body 30. The inner lid 40 can be configured by attaching an inner lid gasket 42 that abuts against the flange of the inner pot to the outer periphery of a disc-shaped inner lid plate 41. In this embodiment, as shown in an exploded view in Figure 4, the inner lid 40 is made up of the inner lid plate 41, inner lid gasket 42, inner lid ring 43, cover gasket 44, and inner lid cover 46, and is equipped with a negative pressure valve 47 and a safety valve 48.

[0024] The inner lid plate 41 has a dish-like shape that is concave downward, and an inner lid packing 42 is detachably attached to the outer periphery.

[0025] The inner lid plate 41 is fitted into the inner lid ring 43. The inner lid ring 43 has locking pieces 43a and 43b on its front and rear ends. The lid body 30 is also provided with a clip 33 that clamps the locking piece 43a and a locking receiving portion 34 into which the locking piece 43b fits, as shown in FIG. 3. After the inner lid 40 has been removed from the lid body 30, as shown in FIG. 2, the inner lid 40 is attached to the lid body 30 by fitting the locking piece 43b into the locking receiving portion 34 and pushing the locking piece 43a into the clip 33.

[0026] A negative pressure valve 47 and a safety valve 48 are attached to the inner lid plate 41 by a resin cover packing 44 and a metal inner lid cover 46 .

[0027] Negative pressure valve 47 is positioned to close negative pressure valve hole 41a in inner lid plate 41. When pressure inside the inner pot becomes high, it closes negative pressure valve hole 41a, and when pressure becomes normal or negative, it opens negative pressure valve hole 41a under its own weight. Furthermore, safety valve 48 is positioned to close safety valve hole 41b in inner lid plate 41, and when pressure inside the inner pot becomes excessive, it opens safety valve hole 41b to release pressure.

[0028] As shown in Fig. 4, a pressure adjustment hole frame 41c is drilled through the inner lid plate 41, and a pressure adjustment hole 45 is provided in the cover packing 44. The pressure adjustment hole 45 can be formed from an elastic material such as a packing material with high sealing properties so that it can abut airtightly with the valve body 70 described below. As shown in Fig. 6, it has a cylindrical hole portion 45a that fits into the pressure adjustment hole frame 41c, and a springy reduced diameter portion 45b that extends upward from the cylindrical hole portion 45a. The reduced diameter portion 45b protrudes from a hole portion 46a provided in the inner lid cover 46.

[0029] A steam sensor (not shown) that detects the temperature of steam in the inner pot is also provided on inner lid plate 41. The steam sensor is an example of the temperature detection means of the present invention.

[0030] Lid 30 has steam passage 35 (part of steam passage 35 is shown in Figure 5) formed directly above inner lid cover 46, through which steam passing from the inner pot through pressure adjustment hole 45 passes, and this passage is connected to pressure adjustment space 36 provided on the rear side of lid 30. Pressure adjustment space 36 cools steam containing sticky substance generated from inside the inner pot, separates the sticky substance from the steam, and releases the steam from exhaust hole 37. The steam release route is indicated by arrow A in the figure.

[0031] A pressure adjustment mechanism 50 is provided in the steam passage 35 above the pressure adjustment hole 45. The pressure adjustment mechanism 50 opens and closes the pressure adjustment hole 45 to adjust the pressure state inside the inner pot.

[0032] The pressure adjustment mechanism 50 includes a valve element 70 that closes the pressure adjustment hole 45 from above, and a solenoid 60 that displaces the valve element 70. The solenoid 60 is a driving means for the pressure adjustment mechanism 50 of the present invention. The valve element 70 can be configured to move in a direction perpendicular to the pressure adjustment hole 45, that is, in FIG. 5 , with the displacement direction being up and down, to open and close the pressure adjustment hole 45. In this embodiment, the solenoid 60 displaces the valve element 70 in the up and down direction.

[0033] 6 and 9, the solenoid 60 has a fixed part 61 and a movable part 65 that is movable up and down relative to the fixed part 61. The fixed part 61 of the solenoid 60 is attached to the solenoid case 39, and the solenoid case 39 is fixed to the cover 30.

[0034] The solenoid 60 may be, for example, a push solenoid, which may be configured so that when energized, the movable part 65 protrudes downward from the fixed part 61 in the displacement direction of the valve body 70, and when de-energized, the movable part 65 retracts upward due to the restoring force of a return spring (in this embodiment, a packing member 90, described later). Energization of the solenoid 60, adjustment of the power value, and cut-off of the energization are performed by a control system (described later in FIG. 11) including the solenoid 60 in response to commands from control means.

[0035] As shown in Fig. 6, the fixed part 61 has a recessed pipe part 61a into which the movable part 65 having the above-mentioned shape is slidably fitted. The pipe part 61a has a fixed part bottom surface 61b at its lower end, and a shaft hole 61c into which the push rod 67 is fitted is formed in the fixed part bottom surface 61b. The fixed part 61 expands in diameter in a conical shape upward from the fixed part bottom surface 61b, and its upper part is cylindrical. The fixed part bottom surface 61b and its upper vicinity constitute the fixed iron core 62. An excitation coil 63 is wound around the pipe part 61a and the fixed iron core 62.

[0036] The movable part 65 can be configured by a push rod 67 protruding from the lower end of a movable core 66 (plunger). The movable core 66 has a cylindrical upper part and a conical lower part tapering in diameter, and has a movable part lower surface 65a facing the fixed part bottom surface 61b. The push rod 67 protrudes downward from the center of the movable part lower surface 65a.

[0037] Between the movable part lower surface 65a and the fixed part bottom surface 61b, there is provided an annular spacer 68 through which the push rod 67 passes. The spacer 68 prevents the fixed part 61 and the movable part 65 from directly adhering to each other, which would cause variations in the set pressure value. It also prevents the fixed part 61 and the movable part 65 from directly colliding with each other, which can reduce the metallic noise that would otherwise be generated by such a collision.

[0038] The solenoid 60 configured as described above varies the strength of the protrusion of the movable part 65 by varying the power supplied to the excitation coil 63. Increasing the power increases the magnetic field strength generated by the excitation coil 63, thereby increasing the downward force of the movable part 65 and the force that biases the valve element 70 toward the pressure adjustment hole 45 (described below). The power adjustment is controlled by a control unit including a transistor or the like. Figure 11 shows a circuit block diagram of the control system of the control unit. As shown in Figure 11, the control system is primarily composed of a microcomputer 12, which serves as the control unit. The microcomputer 12 receives the detection value of the steam sensor 13, and supplies a predetermined amount of power to the solenoid 60 from a power control circuit 14 based on a program, such as a preset rice cooking sequence. The power control circuit 14 is supplied with 26V DC, which is converted from 100V AC from a commercial power source (outlet 15) by an AC / DC power supply 16 for the solenoid. In the illustrated control system, the magnetic field strength of the excitation coil 63 can be adjusted by adjusting the amount of power supplied to the excitation coil 63 of the solenoid 60.

[0039] As shown in FIG. 6, the valve element 70 attached to the solenoid 60 includes a valve plate 71 that closes the pressure adjustment hole 45 and a cylindrical portion 72 that protrudes upward from the valve plate 71. The valve plate 71 is sized and shaped to be able to abut airtightly against the pressure adjustment hole 45. The cylindrical portion 72 fits over the push rod 67, thereby engaging the valve element 70 with the solenoid 60. The upper end of the cylindrical portion 72 has an outward-facing flange 72a. An annular valve element attachment fixture 80 is fitted on the outer periphery of the cylindrical portion 72 between the upper surface of the valve plate 71 and the flange 72a. The valve element attachment fixture 80 has an annular engagement groove 80a formed on its underside, which engages with a packing member 90 (described next). The valve plate 71 also has an upward-facing rim 72b formed on the outer periphery of the valve plate 71 to hold the packing member 90.

[0040] 6 and 9, the valve element 70 and the solenoid 60 are airtightly connected by a packing member 90. This separates the solenoid 60 from the steam passage 35, preventing corrosion of the solenoid 60 due to steam and preventing failure.

[0041] As shown in Figures 6 and 9 and Figures 7 and 10 which show the packing member 90 alone, the packing member 90 has a valve body holding portion 91 which is airtightly connected to the valve body 70, and a flange 92 which is airtightly connected to the solenoid case 39, and the valve body holding portion 91 and the flange 92 are connected by a bellows portion 93.

[0042] The valve disc holding portion 91 is provided at the lower end of the packing member 90 and holds the valve disc 70 via the valve disc mounting fixture 80. A holding groove 91a with a roughly U-shaped cross section that encases the valve disc mounting fixture 80 is formed on the inner periphery of the valve disc holding portion 91. The outer periphery of the valve disc holding portion 91 is sized to fit inside the rim portion 72b of the valve disc 70. An annular engaging protrusion 91b that engages with the engaging groove 80a of the valve disc mounting fixture 80 is formed upward at the inner end of the lower edge of the holding groove 91a.

[0043] As shown in Figures 7 and 10, the flange 92 is an annular member formed on the upper end of the packing member 90. As shown in Figure 5, the flange 92 can be sandwiched between the solenoid case 39 and the solenoid mounting frame 38 provided on the lid 30. When the solenoid 60 is activated, the bellows portion 93, which will be described next, expands and contracts, and the flange 92 may be pulled between the solenoid case 39 and the solenoid mounting frame 38 and fall off. Therefore, in the illustrated embodiment, a retaining portion 92a is formed on the flange 92, as shown in the enlarged view of the circled portion in Figure 5 and in Figure 7. The retaining portion 92a may be formed so that the outer periphery is thicker than the inner periphery, for example. As shown in the enlarged view above, when the flange 92 is clamped between the solenoid case 39 and the solenoid mounting frame 38, the retaining portion 92a engages with the protrusion 38a formed upward on the inner periphery of the solenoid mounting frame 38, preventing the packing member 90 from falling off.

[0044] Furthermore, to prevent steam from entering the solenoid 60 from between the packing member 90 and the solenoid case 39, as shown in the enlarged view of the circled area in Figure 5 and in Figure 7, a triangular rib 92b is provided in an annular shape on the top surface of the flange 92. When the flange 92 is sandwiched between the solenoid case 39 and the solenoid mounting frame 38, the rib 92b comes into contact with the solenoid case 39 and is compressed and deformed, preventing steam from entering.

[0045] The bellows portion 93 airtightly connects the valve disc holding portion 91 and the flange 92. As shown in Figures 7 and 10, the bellows portion 93 expands in diameter upward from the valve disc holding portion 91, and a step is formed midway. The bellows portion 93 has spring properties, and when the bellows portion 93 is expanded as shown in Figure 10, its restoring force causes the valve disc holding portion 91 to contract so as to enter the inside of the flange 92 as shown in Figure 7.

[0046] The packing member 90 and the valve body 70 are configured so that the tubular portion 72 of the valve body 70 does not come off the push rod 67 even when the bellows portion 93 of the packing member 90 is fully extended. Specifically, the bellows portion 93 is adjusted so that the lower end of the push rod 67 remains in the tubular portion 72 when the bellows portion 93 is fully extended. This prevents the tubular portion 72 from coming off the push rod 67 even if the user pulls on the valve body 70 for some reason, and prevents malfunction of the pressure adjustment mechanism 50.

[0047] As shown in Fig. 2, the inner lid 40 is attached to the lid 30 having the pressure adjustment mechanism 50 configured as described above. As a result, the pressure adjustment hole 45 of the inner lid 40 is aligned with the valve body 70, as shown in Figs. 5 and 6.

[0048] In an unloaded state, i.e., when the solenoid 60 is not energized, the restoring force of the packing member 90 causes the valve body 70 to wait in the upper position, as shown in Figures 5 and 6, and open the pressure adjustment hole 45.

[0049] <Cooking program> The rice cooker 10 is used as follows. In the cooking programs below, the pressure control of the present invention is executed during the heating process. The control means receives input from the operation switch 31, receives outputs from a temperature sensor that measures the temperature of the bottom of the inner pot and a steam sensor that measures the temperature of steam inside the inner pot, and adjusts the heater output and the power value of the solenoid 60 according to the cooking program. The heater output affects the temperature of the food being cooked, and the power value of the solenoid 60 affects the set pressure that biases the valve element 70 into the pressure adjustment hole 45.

[0050] First, ingredients are placed in the inner pot, for example, rice and water for rice cooking, and the inner pot is then set in the cooker body 20, and the lid 30 is closed. The inner lid gasket 42 of the inner lid 40 is in airtight contact with the flange of the inner pot. At this time, the solenoid 60 is not yet energized, so the pressure adjustment hole 45 is open.

[0051] A cooking program is executed when the user presses the operation switch 31. For example, in the case of rice cooking, a rice cooking program is executed according to the rice cooking sequence. The rice cooking program can include, for example, processes such as water absorption, heating, cooking, reheating, and steaming.

[0052] The water absorption process is a process in which the rice is soaked in water, and if necessary, the heater is operated at a low temperature to maintain the temperature of the inner pot measured by the steam sensor (or temperature sensor, the same applies below) at, for example, about 30°C.

[0053] Then, in the subsequent temperature-raising process, the amount of electricity supplied to the heater is increased, and the temperature of the inner pot is raised in one go to nearly 100°C. During this time, electricity is started to be supplied to the solenoid 60 (excitation coil 63), keeping the inner pot airtight and increasing the pressure, leading to early boiling.

[0054] Figure 12 shows the temperature detected by the steam sensor, the set pressure in the inner pot (corresponding to the biasing force of solenoid 60), and the cumulative power consumption when a cooking program according to one embodiment is being executed. In Figure 12, the horizontal axis represents elapsed time (minutes), and the figure shows the time from the temperature-raising process that begins at about 30 minutes to about 45 minutes into the reheating process, omitting the water absorption process.

[0055] During the heating process, when the temperature detected by the steam sensor reaches a first temperature threshold (described later), current is applied to the solenoid 60, causing the valve element 70 to close the pressure adjustment hole 45, thereby maintaining an airtight seal inside the inner pot. Specifically, when current is applied to the solenoid 60 of the fixed part 61, a magnetic field is generated in the solenoid 60, magnetizing the movable iron core 66 of the movable part 65. As shown in FIGS. 8 and 9 from the state in FIGS. 5 and 6 to that in FIGS. 8 and 9, the valve element 70 moves downward toward the fixed iron core 62 against the biasing force of the packing member 90 and is attracted thereto. As a result, the valve plate 71 of the valve element 70, which is engaged with the push rod 67 of the movable part 65, closes the pressure adjustment hole 45 in the inner lid 40.

[0056] When the valve body 70 closes the pressure adjustment hole 45, the inside of the inner pot is sealed, and as a result of further increasing the temperature of the inner pot by the heater, the pressure inside the inner pot increases due to steam generated from the ingredients.

[0057] If the solenoid 60 continues to be used at the rated pressure, not only will power consumption increase, but the temperature of the solenoid 60 will also rise. Heat generation in the solenoid 60 will increase the resistance value of the solenoid 60, leading to further increases in power consumption and a shortened lifespan.

[0058] Therefore, in the present invention, in order to reduce the power consumption of the solenoid 60 and suppress heat generation, rather than simply controlling the power supply to the solenoid 60 on and off to operate it at a predetermined set pressure (called the rated pressure), the power value supplied to the solenoid 60 is adjusted in accordance with the expected pressure increase inside the inner pot, thereby reducing power consumption and heat generation as shown in Figure 12.

[0059] The set pressure is controlled by the solenoid 60 within a predetermined temperature range. In this embodiment, as shown in Table 1 below, when the detected temperature inside the inner pot measured by the steam sensor is below the first temperature threshold, the solenoid 60 is not energized. When the temperature is equal to or greater than the first temperature threshold and less than the second temperature threshold, the solenoid 60 is operated with low power consumption to set the set pressure below the rated pressure. When the temperature is equal to or greater than the second temperature threshold, the solenoid 60 is operated to set the set pressure to the rated pressure. This reduces the power consumption of the solenoid 60 and reduces heat generation within the temperature range between the first temperature threshold and less than the second temperature threshold.

[0060] [Table 1]

[0061] In a specific embodiment, the control means stores a table of the detected temperatures (first and second temperature thresholds) of the steam sensor that serve as temperature thresholds, the expected pressure (upper limit) inside the inner pot at each temperature threshold, the set pressure of the solenoid 60, and the power value applied to the solenoid 60 to apply that pressure, as shown in Table 1. For a specific example of the table, see Table 2 in the examples described below.

[0062] The detected temperature of the steam sensor and the expected pressure in the inner pot can be obtained based on the actual measured values ​​when the heater is operated in the rice cooker 10 of this embodiment. The set pressure of the solenoid 60 and the power value applied to the solenoid 60 are values ​​that generate a set pressure slightly higher than the expected pressure when the solenoid 60 is operated in the rice cooker 10 of this embodiment and the valve body 70 is pressed against the pressure adjustment hole 45.

[0063] During the heating process, the heater operates to raise the temperature inside the inner pot. When the temperature detected by the steam sensor reaches the first temperature threshold, the control means supplies power to the solenoid 60. As shown in Table 1, when the temperature detected by the steam sensor is between the first and second temperature thresholds, the power supplied to the solenoid 60 is set to a first supply power value, which is lower than a second supply power value (described below). Specifically, when the solenoid 60 is current-controlled, the first supply current value supplied to the solenoid 60 is set to a value lower than the rated second supply current value. This allows the solenoid 60 to block the pressure adjustment hole 45 with a biasing force higher than the pressure inside the inner pot but lower than the rated pressure, thereby optimizing the pressure. This biasing force is below the rated pressure but higher than the pressure inside the inner pot, so the pressure inside the inner pot is not released through pressure adjustment hole 45, and because the first supply power value supplied to solenoid 60 is also smaller than the rated second supply power value, power consumption in solenoid 60 can be reduced, and heat generation can also be reduced. In detail, the power consumption can be reduced by the product of the time between when the temperature detected by the steam sensor reaches the first temperature threshold and when it reaches the second temperature threshold and the difference between the second supply power value and the first supply power value.

[0064] In Table 1, there are two temperature thresholds, a first temperature threshold and a second temperature threshold, but as shown in the examples, multiple temperature thresholds may be set between the first and second temperature thresholds, and the power supply value may be set proportionally or in stages between each temperature threshold. This further optimizes the pressure inside the inner pot, reducing power consumption and heat generation.

[0065] When the temperature detected by the steam sensor reaches the second temperature threshold while the power supplied to solenoid 60 is set to the first power supply value, the control means changes the power supplied to solenoid 60 to the second power supply value. As a result, as shown in Figure 12, the biasing force of pressure adjustment hole 45 by solenoid 60 becomes large and reaches the rated pressure, so that it can be biased at the rated pressure even if the pressure inside the inner pot increases.

[0066] In the temperature increasing process, if the temperature detected by the vapor sensor remains lower than the second temperature threshold for a certain period of time or longer, it is preferable to reduce the power supplied to the solenoid 60. This can achieve power saving.

[0067] Then, after a predetermined time has elapsed since the start of the rice cooking program, the rice will move on to the cooking process.

[0068] During the cooking process, as shown in Figure 12, heating by the heater continues with the second power value supplied to solenoid 60. Note that when the set pressure in the inner pot during the cooking process exceeds the rated pressure, valve element 70 moves upward against the downward force of movable iron core 66, releasing the pressure, thereby maintaining the rated pressure.

[0069] Towards the end of the cooking process, the heater is energized intermittently, and the set pressure of the inner pot is gradually reduced by decreasing the power supplied to the solenoid 60 (B in Figure 12), causing the water remaining between the rice to boil and stirring the sticky rice. This gradually releases the pressure to the set pressure. Finally, the solenoid 60 is de-energized, and the pressure adjustment hole 45 is opened.

[0070] When the pressure is released, the high-pressure, high-temperature steam and gas containing the sticky paste inside the inner pot pass through pressure adjustment hole 45 and steam passage 35 as shown by arrow A in Figure 5, and reach pressure adjustment space 36. Then, in pressure adjustment space 36, the steam containing the sticky paste is cooled, the steam and sticky paste are separated, and the steam is released from exhaust hole 37.

[0071] In this way, in the present invention, the set pressure in the inner pot can be easily adjusted by adjusting the power applied to the solenoid 60.

[0072] After a predetermined time has elapsed since the start of the rice cooking program, the rice cooker will transition to the reheating process. In this process, the pressure adjustment hole 45 is left open and electricity is passed through the heater to maintain boiling. Once the reheating process is complete, the rice cooker will transition to the steaming process. The steaming process is completed by operating the heater for a predetermined time, and the rice cooking program will end. After this, the heater can be operated as needed to keep the rice warm, etc.

[0073] As a specific embodiment, if the rice cooking program is set to 59 minutes, the water absorption process can be from the start to 21 minutes 39 seconds, the temperature rising process can be from 21 minutes 40 seconds to 34 minutes 14 seconds, the cooking process can be from 34 minutes 15 seconds to 42 minutes 39 seconds, the reheating process can be from 42 minutes 40 seconds to 53 minutes 59 seconds, and the soaking process can be from 54 minutes onwards.

[0074] If power to the rice cooker 10 is cut off during pressurization due to a power outage or the rice cooker being unplugged, power to the solenoid 60 will also be cut off. As a result, as shown in Figures 5 and 6, the restoring force of the packing member 90 causes the valve element 70 to move upward together with the movable part 65, and the valve element 70 moves away from the pressure adjustment hole 45, opening the inner pot to the atmosphere. Therefore, no safety mechanism for releasing pressure in the event of a power outage is necessary. [Example]

[0075] Table 2 is an example of a table stored in the control means. In this example, the first temperature threshold is 60°C, the second temperature threshold is 90°C, and three temperature thresholds (70°C, 80°C, and 90°C) are set at equal intervals between the first and second temperature thresholds. Table 2 shows each temperature threshold, the estimated pressure inside the inner pot, the voltage, current, and power (voltage x current) applied to the solenoid 60, and the power (AC). In this example, a constant voltage (26V) is used, and current control is used. Note that the power (AC) is the power consumption at the outlet 15 when the power efficiency of the AC / DC power supply 16 for the solenoid in Figure 11 is 80%, and is calculated by dividing the power by 80%. All numerical values ​​in the example are for illustrative purposes only and do not limit the invention.

[0076] [Table 2]

[0077] Figure 12 shows the temperature detected by the steam sensor, the set pressure in the inner pot (corresponding to the biasing force of the solenoid 60), and the cumulative power consumption when the cooking program shown in the above embodiment is carried out under the conditions in Table 2. In Figure 12, the horizontal axis represents elapsed time (minutes), and of the total 59 minutes of the rice cooking program, the program shows the period from the temperature-raising process starting at the 30th minute to the 45th minute when the steaming process is completed, omitting the water absorption process and the reheating process afterwards.

[0078] Referring to the figure, during the temperature rise process, the temperature detected by the steam sensor is below the first detection temperature (60°C) until 34 minutes and 14 seconds, so no current is supplied to the solenoid 60 and the set pressure inside the inner pot is atmospheric pressure (1 atmosphere). Then, at approximately 32 minutes and 30 seconds when the temperature detected by the steam sensor reaches the first detection temperature, the first current value (0.1 A) shown in Table 2 is supplied to the solenoid 60, setting the set pressure to 1.05 atmospheres. The graph showing the cumulative power consumption at this time shows a gentler slope than during the pressure cooking process from approximately 34 minutes onwards.

[0079] In this embodiment, the temperature inside the inner pot rises suddenly to the second temperature threshold of 90°C at approximately 34 minutes, making it difficult to understand how the set pressure of the solenoid 60 is controlled by multiple temperature thresholds as shown in Table 2. However, it can be seen that just before reaching the second temperature threshold, the detected temperature is above 80°C and below 90°C, and the set pressure of the solenoid 60 is controlled to 1.15.

[0080] Then, at approximately 34 minutes, the detected temperature reaches the second temperature threshold, the set pressure of the solenoid 60 is maintained at the rated pressure of 1.2 atmospheres, and the slope of the integrated power consumption becomes steeper.

[0081] That is, in this embodiment, the power consumption during the approximately 90 seconds from approximately 32 minutes 30 seconds to approximately 34 minutes can be reduced, the set pressure can be optimized, and heat generation by the solenoid 60 can be reduced.

[0082] Figure 13 is a comparative example, showing a graph in which the pressure control of the present invention is not performed, and 3.64 W of power is supplied to the solenoid 60 so that the rated pressure becomes 1.2 atmospheres when the temperature detected by the steam sensor reaches the first detection temperature (60°C) during the temperature rising process. In Figure 13, after the temperature detected by the steam sensor reaches the first detection temperature, the same rated pressure is maintained even in the pressure cooking process.

[0083] Figure 14 is a graph that overlaps Figure 12 and Figure 13. Referring to the figure, it can be seen that the example of the invention was able to reduce and optimize the set pressure between approximately 32 minutes 30 seconds and approximately 34 minutes, which resulted in a reduction in the power consumption of the solenoid 60 at the circled area C, and a reduction in the cumulative power consumption.

[0084] The above description is for the purpose of explaining the present invention, and should not be construed as limiting the invention described in the claims or narrowing its scope. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims. [Explanation of symbols]

[0085] 10 Rice cooker (cooking appliance) 20 Cooking appliance body 30 Lid 36 Pressure adjustment space 40 Inner lid 45 Pressure adjustment hole 50 Pressure adjustment mechanism 60 Solenoid (driving means) 70 Valve body

Claims

1. The inner pot and a cooking appliance body that houses the inner pot and includes a heating means for heating the inner pot; a lid that closes the cooking appliance body; An inner lid attached to the lid body and covering the inner pot, the inner lid having a pressure adjustment hole therethrough; a pressure adjustment mechanism including a valve body that opens and closes the pressure adjustment hole, and a driving means that urges the valve body toward the pressure adjustment hole, the driving means having a set pressure that urges the valve body variable in accordance with a supplied power value; a temperature detection means capable of measuring the temperature inside the inner pot; a control means; A cooking device having the control means sets the supply power value to the drive means to zero when the temperature detected by the temperature detection means is lower than a first temperature threshold, sets the supply power value to a first supply power value when the detected temperature is equal to or higher than the first temperature threshold and lower than a second temperature threshold higher than the first temperature threshold, and sets the supply power value to a second supply power value higher than the first supply power value when the detected temperature is equal to or higher than the second temperature threshold. Heating cooker.

2. the control means has a plurality of temperature thresholds set between the first temperature threshold and the second temperature threshold, and sets the supply power value for each of the temperature thresholds. The cooking device according to claim 1 .

3. the control means sets the plurality of temperature thresholds at equal intervals between the first temperature threshold and the second temperature threshold, and changes the supply power value proportionally to each temperature threshold; The cooking device according to claim 2 .

4. the control means reduces the value of the power supplied to the driving means when the detected temperature is lower than the second temperature threshold for a certain period of time. The cooking device according to claim 3.

5. The temperature detection means is a steam sensor that detects the temperature of steam in the inner pot. The cooking device according to any one of claims 1 to 4.

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