Manufacturing method for the inner pot of a non-stick pot

Abstract

The present invention discloses a method for manufacturing an inner pot (30) of a non-stick pot, comprising the steps of: providing a metal plate material having at least an outer metal layer (321), a heat-soaking layer (322), and an inner metal layer (323); etching, engraving, or pressing the inner metal layer (323) to form an anti-stick array (33) including a plurality of grooves or protrusions; stretching the metal plate material with the anti-stick array (33) by controlling the tensile rate to manufacture the inner pot (30); or stretching the metal plate material with the anti-stick array (33) by controlling the tensile rate to produce an inner pot blank (S04); and adjusting the expansion rate. and (S06) manufacturing the inner pot (30) by controlling the expansion of the inner pot blank. The thickness ratio between the side wall and the bottom wall of the manufactured inner pot (30) is 0.9 to 1.1, and the thickness ratio between the outer metal layer (321) and the inner metal layer (323) is 0.6 to 1.4, so that the grooves or protrusions deformed by tension in the anti-stick array (33) are within a predetermined range, and the area change of the area where the grooves or protrusions are located is within a controllable range, so that the rice and the anti-stick array (33) on the side wall of the inner pot (30) are in excellent contact with each other.

Description

[Technical Field]

[0001] This application claims priority from a Chinese patent application filed with the China Patent Office on February 14, 2023, bearing application number CN202310112004.8 and entitled "Method for manufacturing the inner pot of a non-stick pot," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of kitchen appliances, and in particular to a method for manufacturing the inner pot of a nonstick pot. [Background technology]

[0003] Conventional non-stick pots have protrusions or grooves on their inner surface, and a non-stick coating is applied to the grooves so that when a spatula scrapes against the surface of the pot during cooking, the non-stick coating in the grooves is less likely to be scraped off, thereby extending the service life of the non-stick coating. However, in the process of forming the inner pot, the inner pot structure is generally formed by deforming a blank using processing methods such as press forming and expansion, and depending on the shape of the inner pot side wall, the inner pot structure is divided into a straight inner pot and a spherical inner pot. Specifically, for a straight inner pot, the shape of the inner pot is formed by a first press forming, while for a spherical inner pot, the shape is formed by a first press forming and a second expansion forming, and during the blank elongation and extrusion process, the metal sheet in the center of the mold forms the bottom wall of the inner pot, and the metal sheet in the peripheral part forms the side wall of the inner pot. When grooves and protrusions are formed on the surface of a metal plate, the stretched portions of the metal plate will cause deformation of the grooves and protrusions. Excessive deformation will affect the non-stick performance of the inner pot. Attempts to eliminate this deformation will increase manufacturing costs and difficulties, result in low manufacturing efficiency, and a high reject rate. The deformation mainly occurs on the side walls of the inner pot. Generally, the side walls of woks and frying pans are not the main cooking area, so for woks and frying pans, the requirements for non-stick performance of the side walls are low and the impact of deformation can be ignored. However, for inner pots that are mainly used for serving food, the side walls come into frequent contact with food and the impact of deformation must be taken into consideration. Furthermore, the non-stick coating applied in the grooves cannot guarantee that hard and fine particulate matter will not come into contact with the non-stick coating in the grooves. If this problem occurs, the non-stick performance cannot be guaranteed. Therefore, non-stick without a coating is currently a common pursuit in the industry. Summary of the Invention [Problem to be solved by the invention]

[0004] In order to solve at least one of the above technical problems, the present application provides a method for manufacturing the inner pot of a non-stick pot. [Means for solving the problem]

[0005] The technical proposal of this application is as follows: A method for manufacturing an inner pot of a non-stick pot, providing a metal plate material having at least an outer metal layer, a heat-soaking layer and an inner metal layer combined therewith, and etching, engraving or pressing the inner metal layer side to form an anti-adhesive array including a plurality of grooves or protrusions; The method includes the steps of: stretching the metal plate provided with the anti-adhesive array by controlling the stretching rate to manufacture the inner kettle; or stretching the metal plate to form an inner kettle blank by controlling the stretching rate, and then expanding the inner kettle blank by controlling the expansion rate to manufacture the inner kettle; By setting the thickness ratio between the side wall of the manufactured inner pot and the bottom wall of the inner pot to 0.9 to 1.1, and the thickness ratio between the outer metal layer and the inner metal layer to 0.6 to 1.4, the grooves or protrusions in the anti-adhesive array that are stretched and deformed meet the specified range.

[0006] In a preferred embodiment of the present application, the stretched and deformed grooves or protrusions in the anti-adhesive array are located on the side wall, and the deformation ratio along the axial direction of the side wall of the inner pot is 1.1 to 1.8 times.

[0007] In a preferred embodiment of the present application, the stretched and deformed grooves or protrusions in the anti-adhesive array are located on the side wall, and the deformation ratio along the circumferential direction of the side wall of the inner kettle is 0.5 to 1.01 times.

[0008] In a preferred embodiment of the present application, the equivalent diameter of the groove or protrusion on the bottom wall of the inner pot is D, the thickness of the inner metal layer is H1, and the equivalent diameter D satisfies the following relationship: 0.08≦D / H1≦3.

[0009] In a preferred embodiment of the present application, the grooves or protrusions in the anti-adhesive array that are stretched and deformed are located on the side wall, and the maximum diameter of the grooves on the side wall of the inner pot after deformation is 1620 μm or less.

[0010] In a preferred embodiment of the present application, the stretched grooves or protrusions in the anti-adhesive array are located on the side wall, and the minimum diameter of the side wall of the inner pot after deformation is 50 μm or more.

[0011] In a preferred embodiment of the present application, the ratio of the thickness of the outer metal layer to the thickness of the metal plate is 0.2 to 0.4.

[0012] In a preferred embodiment of the present application, the ratio of the thickness of the inner metal layer to the thickness of the metal plate is 0.1 to 0.4.

[0013] In a preferred embodiment of the present application, the ratio of the heat-equalizing layer to the thickness of the metal plate is 0.2 to 0.7.

[0014] In a preferred embodiment of the present application, the grooves in the anti-adhesive array are not connected to each other but are separate recesses that are independent of each other, and the adhesive array in the middle of the bottom wall of the inner pot covers the temperature measuring device. [Effects of the Invention]

[0015] According to the above technical solution, the beneficial effects obtained by the present application are as follows: In some embodiments of the present invention, in order to maintain the deformation amount of the anti-stick array within a predetermined range, the thickness ratio between the side wall and the bottom wall of the manufactured inner pot is 0.9 to 1.1, the thickness ratio between the outer metal layer and the inner metal layer is 0.6 to 1.4, and further, the deformation ratio of the area defined by the circumferential and axial directions is between 1.1 and 0.9, so that the area change of the area where the grooves or protrusions are located falls within a controllable range, thereby maintaining excellent contact between the rice and the anti-stick array on the side wall of the inner pot.

[0016] The drawings described herein are intended to provide a further understanding of the present application, constitute a part of the present application, and the illustrative embodiments and descriptions thereof should not be construed as forming an undue limitation of the present application, but are intended to be used for interpreting the present application. [Brief explanation of the drawings]

[0017] [Figure 1]1 is a cross-sectional view of a cooking utensil provided by an embodiment of the present application. [Figure 2] FIG. 2 is a cross-sectional view of an inner pot provided by an embodiment of the present application. [Figure 3] FIG. 2 is a plan view of an inner pot structure provided by an embodiment of the present application. [Figure 4-1] 1 is an electron microscope image of a cross section in the thickness direction of the bottom wall of the inner pot in a specific embodiment of the present application. [Figure 4-2] 1 is an electron microscope image of a thickness direction cross section of a side wall of an inner pot in a specific embodiment of the present application. [Figure 5-1] 1 is an electron microscope image of the anti-stick array on the bottom wall of the inner pot in a specific embodiment of the present application; [Figure 5-2] 1 is an electron microscope image of an anti-stick array on the side wall of the inner pot in a specific embodiment of the present application. [Figure 6] 10 is a diagram showing the distribution of regions where anti-adhesive arrays are formed on a metal plate in Example 2 of the present application. [Figure 7-1] FIG. 10 is a local enlarged view of a groove on region S1 provided in Example 2 of the present application. [Figure 7-2] FIG. 10 is a local enlarged view of the groove on region S2 provided in Example 2 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0018] In order to clearly explain the overall concept of the present application, the following detailed description will be given in an exemplary form in conjunction with the drawings of the specification.

[0019] In order to fully understand the present application, numerous specific details are set forth in the following description; however, the present application may also be embodied in other different forms, and the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0020] Furthermore, in the description of this application, the orientations or positional relationships indicated by terms such as "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" are orientations or positional relationships according to the drawings, and do not indicate or imply that the indicated devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and are merely intended to conveniently describe and simplify the description of this application, and do not limit the application.

[0021] In this application, unless otherwise expressly specified or limited, the terms "attached," "coupled," "connected," "fixed," etc. should be understood in a broad sense, and may mean, for example, a fixed connection, a detachable connection, or an integral connection, or a mechanical connection, an electrical connection, a communicative connection, a direct connection, an indirect connection through an intermediate medium, or even an internal communication between two elements or an interactive relationship between two elements. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0022] Unless otherwise expressly specified or limited, in this application, a first feature being "above" or "below" a second feature indicates that the first and second features are in direct contact with each other or that the first and second features are in indirect contact with each other via an intermediate medium. In this description, references such as "one embodiment," "some embodiments," "exemplary," "particular examples," or "some examples" indicate that the specific feature, structure, material, or feature described in connection with the embodiment or example is included in at least one embodiment or example of this application. In this specification, the use of exemplary terms does not necessarily refer to the same embodiment or example. Furthermore, the specific feature, structure, material, or feature described may be combined in any suitable manner in any one or more embodiments or examples.

[0023] This application proposes a method for manufacturing an inner pot of a non-stick pot, and particularly relates to a method for manufacturing an inner pot for cooking rice without a coating, which is mainly used for cooking rice, and which may be a rice cooker or a pressure cooker, or in some other embodiments, other cookware with a rice cooking function. This application also proposes an inner pot for cooking rice without a coating, which is manufactured by the above manufacturing method.

[0024] The cookware cooks rice using an inner pot with or without a coating. Conventional inner pots are generally coated inner pots, that is, the inner surface of the inner pot is coated with Teflon (scientific name: polytetrafluoroethylene; English abbreviation: PTFE). The uncoated inner pot of the present application, in contrast to the coated inner pot, has no coating on the base material of the inner pot. Therefore, the inner wall of the inner pot is a metal layer that can come into contact with food, which may be stainless steel. During cooking, the food comes into direct contact with and cooks through the metal layer of the inner pot, thereby eliminating the problem of the coating falling off of the coated inner pot and the dietary health issues caused by the coating itself.

[0025] Referring to Figure 1, a rice cooker is shown, which comprises a pot body 10, a pot lid 20 and an inner pot 30, the inner pot 30 is installed inside the pot body 10, the inside of the inner pot 30 contacts the rice via an inner metal layer 323, the pot lid 20 covers the pot body 10, and the pot body 10 is equipped with a heating device 105 for heating the inner pot 30. During the cooking process, a mixture of rice and water is added to the cooking cavity 301 inside the inner pot 30, and the rice is cooked by heating with the heating device 105 at the bottom of the inner pot 30.

[0026] The inner pot of this application is formed with an anti-sticking array by etching, engraving or pressing, and the anti-sticking array has a number of grooves or protrusions, and when the rice comes into contact with the protrusions, the presence of the protrusions and grooves reduces the contact area between the rice and the inner pot and changes the contact angle between the rice and the inner pot, further realizing the rice's non-sticking. In manufacturing the inner pot, the grooves or protrusions are formed in a metal plate, and then the plate is drawn into a tubular structure using a mold.

[0027] The inner pot of the present application uses a composite metal plate, which, as shown in Figures 4-1 and 4-2, includes at least a composite outer metal layer 321, a heat-equalizing layer 322, and an inner metal layer 323. The inner metal layer 323 is located on the rice-serving side of the inner pot and meets food hygiene requirements. The base material of inner metal layer 323 is stainless steel, and the base material of heat-equalizing layer 322 has a high thermal conductivity to facilitate rapid heat conduction and ensure uniform heating of the inner pot. The heat-equalizing layer 322 is made of aluminum. The outer metal layer 321 is located on the outside of the inner pot and generates heat under the action of a magnetic field or protects the heat-equalizing layer 322. The outer metal layer 321 is made of stainless steel. In some other embodiments, the metal plate includes at least a composite heat-equalizing layer 322 and an inner metal layer 323.

[0028] In a specific embodiment of the present application, as shown in Figures 1, 2 and 3, the inner pot 30 includes a bottom wall 31, a side wall 32 and a cooking cavity 301, and is arranged so that the top of the cooking cavity 301 is open. The side wall 32 has a depth direction extending from the bottom wall 31 side to the open side of the cooking cavity 301 and a circumferential direction extending along the circumferential direction of the bottom wall 31. The inner metal layer 323 side of the inner pot 30 is etched, engraved or pressed to form an anti-stick array 33 including a plurality of grooves or protrusions, and the etching is performed by etching the inner metal layer 323. It is a processing technology that removes metal from the surface of stainless steel by eroding the surface of the metal layer 323. Engraving can be laser engraving or mechanical engraving. Laser engraving processing technology is based on digital control technology and uses a laser as a medium, and achieves the processing purpose by using the laser irradiation to instantly melt and gasify the processing material, resulting in physical transformation. Pressing uses a press molding machine to apply external force to the plate material, and the plate material is directly subjected to the distortion force in the mold and distorts. Etching and engraving are material removal manufacturing methods, while pressing is a deformation manufacturing method.

[0029] In a specific embodiment of the present application, in order to control the deformation of the grooves and protrusions to meet a predetermined range, the following manufacturing method for the inner pot of a non-stick pot is proposed, which is mainly achieved by controlling the change in the thickness of the inner pot, and specific reference is made to the following:

[0030] Example 1: The method includes the steps of providing a metal plate material having at least an outer metal layer 321, a heat-soaking layer 322, and an inner metal layer 323, and etching, engraving, or pressing the inner metal layer 323 to form an anti-adhesive array 33 having a plurality of grooves or protrusions; stretching the metal plate material provided with the anti-adhesive array 33 by controlling the tensile rate to manufacture an inner pot; or stretching the metal plate material to form an inner pot blank by controlling the tensile rate, and then expanding the inner pot blank by controlling the expansion rate to manufacture an inner pot; and setting the thickness ratio of the side wall of the manufactured inner pot to the bottom wall of the inner pot to 0.9 to 1.1, and the thickness ratio of the outer metal layer 321 to the inner metal layer 323 to 0.6 to 1.4, so that the grooves or protrusions deformed by stretching in the anti-adhesive array 33 fall within a predetermined range.

[0031] In Examples 1 and 2 and some other specific embodiments of the present application, the ratio of the plastic elongation length of a material to the length of the original sample is the tensile ratio, or elongation ratio, or elongation ratio. Taking 304 stainless steel as an example, an elongation ratio of more than 40% means that 1 mm of stainless steel can elongate at least 0.4 mm. To ensure smooth production of the inner pot, the manufacturing method of this application controls the tensile ratio during the pulling process to ensure that it does not exceed the maximum tensile ratio of the metal material used, thereby avoiding material fracture and necking. In addition to ensuring the above basic premise, if an anti-stick array 33 is present, it should be considered that the anti-stick effect of the anti-stick array 33 will be weakened due to tensile deformation. During the pulling process, the metal plate will expand, causing deformation of the anti-stick array 33. Specifically, the axial size of the grooves of the anti-stick array 33 may increase, and the circumferential size may decrease or increase. In this case, the grooves will deviate from their original shape before deformation, changing the optimal contact shape between the rice and the surface of the inner pot, and reducing the non-stick effect of the rice on the side walls of the inner pot.

[0032] In Examples 1 and 2 and some other specific embodiments of the present application, in accordance with the fundamental principle that the density of a metallic material remains unchanged after plastic deformation, as is well known, the mass remains unchanged before and after deformation. To maintain the same density before and after deformation, the volume before and after deformation must also be the same, where volume = length * width * thickness. Specifically, the length direction is the axial direction of the inner casing side wall, the width direction is the circumferential direction of the inner casing side wall, and the thickness direction is the thickness direction of the inner casing side wall. In this way, the relationship between the axial, circumferential, and left-right deformation of the inner casing side wall is obtained, and the magnitude of the deformation in the thickness direction depends on the axial and circumferential deformation patterns. In other words, the magnitude of the deformation in the thickness direction indirectly reflects the magnitude of the axial and circumferential deformation. This further enables the deformation of the anti-adhesive array 33 in the circumferential and axial directions to be obtained, thereby preventing excessive deformation of the anti-adhesive array 33.

[0033] In Examples 1 and 2 and some other specific embodiments of the present application, the magnitude of deformation in the thickness direction during the stamping manufacturing process is controlled by the size and shape of the cavity between the front and rear dies of the mold, or the expansion pressure. Controlling the deformation of the anti-stick array 33 according to the size in the thickness direction, as opposed to directly controlling the circumferential and axial deformation rates of the anti-stick array 33, conforms to the control logic of the main parameters of the mold during the stamping manufacturing process, is simple and convenient to control, can ensure the consistency of the product molding, and high-quality product manufacturing can be achieved. The deformation amount of the anti-stick array 33 can be easily controlled, avoiding excessive deformation and ensuring the non-stick effect of the side wall of the inner pot. Specifically, in Example 1 of the present application, in order to keep the deformation amount of the anti-stick array 33 within a predetermined range, the thickness ratio of the manufactured inner pot side wall to the inner pot bottom wall is set to 0.9 to 1.1, and the deformation ratio of the area of ​​the region formed in the circumferential direction and the axial direction is set to between 1.1 and 0.9, so that the area change of the region where the grooves or protrusions are located falls within a controllable range, and further, excellent contact between the rice and the anti-stick array 33 on the inner pot side wall is maintained. Preferably, the thickness ratio a of the inner pot side wall to the inner pot bottom wall is between 1.01 to 1.1, and if the ratio of decrease and increase in the axial direction is the same as that in the circumferential direction, the relationship between the deformation rate X and a is 1-X 2= 1 / a, and solve to obtain X∈[10%, 30%], which means that the minimum circumferential reduction rate is 10% and the maximum is about 30%, which avoids forming slits in the grooves.

[0034] In Example 1 of the present application, the thickness ratio a of the inner pot side wall to the inner pot bottom wall may also be 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1, 1.02, 1.3, 1.04, 1.05, 1.06, 1.07, 1.08, or 1.09, so that the area change of the region where the grooves or protrusions are located falls within a reasonable range. Figure 4-1 is an enlarged cross-sectional view of the inner pot bottom wall taken under an electron microscope, with the inner pot bottom wall having a thickness of 1.243 mm, and Figure 4-2 is an enlarged cross-sectional view of the inner pot side wall taken under an electron microscope, with the inner pot side wall having a thickness of 1.295 mm, with the ratio being 1.04.

[0035] In Examples 1 and 2 and some other specific embodiments of the present application, in the press-forming process, in the area of ​​the deformed material that is subjected to large tensile stress, some of the material will become significantly thinner and even break; in the area of ​​the deformed material that is subjected to large compressive stress, when the compressive stress exceeds the critical stress, the material will lose stability and wrinkles will occur. On the other hand, in the composite metal sheet, when the inner casing is deformed, the outer metal layer 321 is mainly subjected to tensile stress and tends to become thinner, while the inner metal layer 323 is mainly subjected to compressive stress and tends to become thicker. Therefore, in Example 1 of the present application, in order to avoid excessive deformation of the thickness size of the composite metal sheet, the thickness difference between the inner metal layer and the outer metal layer 321 should not be too large, and the thickness should be as consistent as possible, so that the thickness direction of the inner metal layer 323 can be easily deformed. To avoid excessively large shrinkage stress and therefore excessive groove depth, the thickness ratio of the outer metal layer to the inner metal layer 323 should be 0.6 to 1.4. If the inner metal layer 323 is too thick and the outer metal layer 321 is too thin, the outer metal layer 321 will expand more easily than the inner metal layer 323, resulting in deeper grooves. If the inner metal layer 323 is too thin and the outer metal layer 321 is too thick, the inner metal layer 323 will expand more easily than the outer metal layer 321, resulting in shallower grooves. Both increasing and decreasing the depth of the grooves affect the optimal contact between the rice and the anti-stick array 33, and the grooves of the anti-stick array 33 must be kept within a reasonable deformation range to ensure the non-stick performance of the inner pot sidewall.

[0036] In Example 1 of the present application, the thickness ratio of the outer metal layer to the inner metal layer 323 is specifically 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, and 1.4. The specific value of the inner metal layer 323 is 0.35 to 0.8 mm. The ratio of the outer metal layer to the inner metal layer in FIG. 4-1 is 464.5 μm / 428.1 μm=1.08, and the ratio of the outer metal layer to the inner metal layer in FIG. 4-2 is 463.6 μm / 463.6 μm=1.

[0037] In Examples 1 and 2 and some other specific embodiments of the present application, the bottom wall of the inner pot is a generally flat portion of the bottom of the inner pot, and the side wall of the inner pot is a portion of the inner pot wall connected to the flat portion of the bottom of the inner pot and extending toward the mouth of the pot, including, but not limited to, an arc-shaped side wall that transitions upward in an arc. If the inner pot is a straight-type rice cooker inner pot (abbreviated as "straight inner pot"), it further includes a vertical side wall portion extending toward the mouth of the pot, and if it is a spherical-type rice cooker inner pot (abbreviated as "spherical inner pot"), it further includes a spherical wall portion extending toward the mouth of the pot and protruding outward from the inner pot. The inner pot in Figure 2 is a spherical inner pot.

[0038] In Example 1 of this application, different manufacturing processes are used according to different inner pot shapes. For a straight inner pot, the manufacturing process is as follows: S01: Etching, engraving, or pressing on the inner metal layer side to form an anti-adhesive array; S03: Produce an inner pot by pulling the metal plate provided with the anti-adhesion array by controlling the pulling rate; For the spherical inner pot, the manufacturing process is as follows: S02: Etching, engraving, or pressing on the inner metal layer side to form an anti-adhesive array; S04: Control the tension rate and pull the inner pot blank; S06: The inner kettle blank is expanded by controlling the expansion rate to manufacture the inner kettle.

[0039] The inner kettle blank is subjected to a primary press forming process using a press forming machine, and then a secondary expansion process is performed using a hydraulic forming machine.

[0040] In Example 1 of the present application, the grooves or protrusions in the anti-adhesive array 33 that are stretched and deformed fill a predetermined range, and may be the rate of change in the area of ​​the region where the grooves or protrusions are located, the rate of change in the circumferential size of the grooves or protrusions, or even the rate of change in the axial size of the grooves or protrusions.

[0041] Specifically, in Example 1 of the present application, the predetermined ranges are as follows: The grooves or protrusions of the anti-adhesive array 33 that have been stretched and deformed are located on the side wall, and the deformation ratio b along the axial direction of the side wall of the inner pot is 1.1 to 1.8 times, which is the ratio between the axial size of the anti-adhesive array 33 on the side wall of the inner pot after being stretched and the corresponding size (preliminary axial size) of the anti-adhesive array 33 on the bottom wall of the inner pot.

[0042] During the pulling process, the axial size will increase, and the axial deformation should not be too large, otherwise the width of the groove will be too large, which will result in poor non-stick effect of the rice.

[0043] As described above, in this embodiment, the grooves or protrusions in the anti-adhesive array 33 that are stretched and deformed are located on the side wall, and the deformation ratio c along the circumferential direction of the side wall of the inner pot is 0.5 to 1.01 times, which is the ratio between the circumferential size of the anti-adhesive array 33 on the side wall of the inner pot after being stretched and the corresponding size (preliminary circumferential size) of the anti-adhesive array 33 on the bottom wall of the inner pot.

[0044] According to the principle that the volume remains constant before and after deformation, when the thickness deformation is ±10%, the axial deformation must not exceed 1.8 to avoid the circumferential shrinkage rate falling below 50%. If the circumferential shrinkage rate is too high and the axial elongation rate is too large, the side wall grooves will become elongated and slit, which will easily trap starch particles or other food residue in the grooves, making the inner pot wall difficult to clean. Long-term accumulation of dirt will affect food hygiene, promote odor transfer, and affect the cooking experience. By keeping the axial deformation ratio above 1.1 and the circumferential elongation rate below 1%, the circumferential and axial dimensions of the grooves will not be too large. If rice grains are easily stuck in the grooves, they will be heated three-dimensionally within the grooves. This will cause the rice starch to become more gelatinized, resulting in stickiness and difficulty in removing the rice, resulting in poor non-stick properties.

[0045] In Example 1 of the present application, the values ​​of the deformation ratio b are specifically 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, and 1.8, and the values ​​of the deformation ratio c are specifically 0.5, 0.6, 0.7, 0.8, 0.9, 1, and 1.01. The anti-adhesive array 33 on the bottom wall of the inner pot is the anti-adhesive array 33 covering the temperature measuring device in the middle of the bottom wall of the inner pot. Figure 5-1 is an electron microscope image of the anti-adhesive array on the bottom wall of the inner pot, with the groove diameter being 455.2 μm. Figure 5-2 is an electron microscope image of the anti-adhesive array on the side wall of the inner pot, with the groove having an axial size of 585.9 μm and a circumferential size of 324.6 μm. Thus, the specific value of deformation ratio b is 585.9 / 455.2=1.287, and the specific value of deformation ratio c is 324.6 / 455.2=0.713.

[0046] In another specific embodiment of the present application, in order to control the deformation of the grooves and protrusions to meet a predetermined range, a method for manufacturing an inner rice cooker without coating is further proposed as follows, which is mainly realized by the principle of pre-deformation, and is specifically as follows:

[0047] Example 2: A method of manufacturing a metal plate comprising at least an inner metal layer 323 and a heat-soaking layer 322; etching, engraving, or pressing the inner metal layer 323 to form an anti-adhesive array 33 comprising a plurality of grooves and protrusions; stretching the metal plate provided with the anti-adhesive array 33 to manufacture an inner pot, or stretching the metal plate into an inner pot blank and then expanding the inner pot blank to manufacture an inner pot. When etching, engraving, or pressing the anti-adhesive array, the grooves and protrusions in the metal plate portion used to manufacture the side walls of the inner pot are smaller in axial dimension than those in the metal plate portion used to manufacture the bottom wall of the inner pot, and the grooves in the former are larger in circumferential direction than those in the metal plate portion used to manufacture the bottom wall of the inner pot, so that the grooves and protrusions in the anti-adhesive array 33 deformed by stretching are within a predetermined range.

[0048] Example 2 of this application is similar to Example 1, but uses different manufacturing processes according to different inner pot shapes. For a straight inner pot, the manufacturing process is as follows: S01: Etching, engraving, or pressing on the inner metal layer side to form an anti-adhesive array; S03: Pulling the metal plate provided with the anti-adhesive array to manufacture the inner pot; For the spherical inner pot, the manufacturing process is as follows: S02: Etching, engraving, or pressing on the inner metal layer side to form an anti-adhesive array; S04: Pull as inner pot blank; S06: The inner kettle blank is expanded to manufacture the inner kettle.

[0049] The inner kettle blank is subjected to a primary press forming process using a press forming machine, and then a secondary expansion process is performed using a hydraulic forming machine.

[0050] During the plastic deformation of metal, the grooves and protrusions on the side wall of the inner pot will be deformed, and after deformation, the anti-stick array 33 will change the optimal contact form between the rice and the anti-stick array 33, which will deteriorate the non-stick effect of the rice on the side wall of the inner pot.

[0051] First, the thickness of the side wall of the inner pot is controlled to be maintained within a controllable range before and after deformation. Then, the area deformation ratio of the anti-adhesive array 33 in the other two directions of the location area is obtained, and according to the possible deformation parameters, preliminary deformation in the opposite direction is performed on the shape and size of the grooves and protrusions of the anti-adhesive array 33 before being pulled, so that the deformation of the grooves on the side wall of the manufactured inner pot is controlled within a predetermined range.

[0052] Specifically, when etching, engraving, or stamping the anti-stick array, the grooves and protrusions on the metal plate portion used to manufacture the side wall of the inner pot have a smaller preliminary axial size than the grooves on the metal plate portion used to manufacture the bottom wall of the inner pot, and the preliminary circumferential size of the grooves on the former is larger than the preliminary axial size of the grooves on the latter.

[0053] The preliminary axial size is the axial size of the side wall surface of the inner kettle after manufacturing, and the preliminary circumferential size is the circumferential size of the side wall surface of the inner kettle after manufacturing. For example, before being drawn, taking the center point of the sheet material as the basis, the radial size of each groove passing through the center point is generally the preliminary axial size, and the size perpendicular to the radial direction is the preliminary circumferential size.

[0054] FIG. 6 shows a metal sheet before it is drawn. When step S01 or S02 is performed on the metal sheet, region S2 will form the bottom wall of the inner pot after drawing, and region S1 will form the side wall of the inner pot after drawing. If this is the case, a preliminary deformation is performed on the groove shape of region S1. As shown in FIGS. 7-1 and 7-2, taking a circular groove as an example, a circular groove is formed in region S2 which will form the bottom wall of the inner pot, and its dimensions W2 and L2 are both diameters. An oval groove is formed in region S1 which will form the side wall of the inner pot, with the major axis of the oval roughly oriented in the preliminary circumferential direction and the minor axis of the oval roughly oriented in the preliminary axial direction.

[0055] After the inner pot is manufactured, it is pre-deformed to form an oval groove, with its preliminary axial dimension L1 being longer and its preliminary circumferential dimension W1 being shorter. Finally, the axial and circumferential dimensions of the grooves on the side walls of the inner pot are similar to the dimensions (W2, L2) of the grooves on the bottom wall of the inner pot. Furthermore, the deformation of the side wall grooves is controlled within a predetermined range to ensure a non-stick effect.

[0056] In Example 2 of the present application, the predetermined range is the ratio between the size of the axial groove on the side wall of the inner hook and the size of the groove on the bottom wall of the inner hook after being pulled, and the ratio range is 0.9 to 1.25.

[0057] During the pulling process, the axial size increases, but the axial deformation should not be too large, otherwise the width of the groove will be too large and the non-stick effect of the rice will be poor. After the pre-deformation process, the difference in shape between the groove on the side wall of the inner pot and the groove on the bottom of the inner pot is not too large, which can better guarantee the non-stick effect of the rice in the inner pot.

[0058] The predetermined range is the ratio of the size of the circumferential groove on the side wall of the inner hook to the size of the groove on the bottom wall of the inner hook after being pulled, and the ratio ranges from 0.8 to 1.01.

[0059] During the deformation process, there is a large possibility of reduction in the circumferential size. Similarly, after the pre-deformation process, due to the circumferential size, the difference between the grooves on the side wall of the inner pot and the grooves on the bottom wall of the inner pot is not too large, which further ensures the non-stick effect of the rice.

[0060] In Example 2 of the present application, the ratio of the size of the axial groove to the size of the groove on the bottom wall of the inner hook may be specifically 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, or 1.25, and the ratio of the size of the circumferential groove to the size of the groove on the bottom wall of the inner hook may be specifically 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, or 1.25.

[0061] Similarly, by maintaining the thickness of the inner wall within a controllable range before and after deformation, the anti-adhesion array 33 is pre-deformed to a pre-axial size and a pre-circumferential size before being pulled.

[0062] In this way, before being pulled, the depth of the grooves and protrusions in the metal plate portion for manufacturing the side wall of the inner kettle is equal to the depth of the grooves in the metal plate portion for manufacturing the bottom wall of the inner kettle.

[0063] By making the depth of the groove in the latter before being pulled equal to the depth of the groove in the former, pre-deformation is not performed on the thickness, but pre-deformation is performed on the preliminary axial size and preliminary circumferential size, thereby reducing the difficulty of pre-deformation.

[0064] The predetermined range is the ratio of the depth of the groove on the side wall of the inner hook to the depth of the groove on the bottom wall of the inner hook after being pulled, and the ratio ranges from 0.9 to 1.1.

[0065] In the press molding manufacturing process, the magnitude of the depth-wise deformation of the groove is controlled by the size and shape of the cavity between the front and rear dies of the mold, or the expansion pressure, which is convenient to control, simple and efficient.

[0066] In Example 2 of the present application, the ratios of the depth of the groove in the side wall to the depth of the groove in the bottom wall of the inner rice cooker are specifically 0.9, 0.95, 1, 1.05, and 1.1. As shown in FIGS. 4-1 and 4-2, the depth of the groove in the bottom wall of the inner rice cooker is 428.1-327.9=100.2 μm, and the depth of the groove in the side wall of the inner rice cooker is 463.6-354.5=109.1 μm, with the ratio being specifically 1.08.

[0067] The technical solutions of Examples 1 and 2 and some other specific embodiments of the present application will now be introduced as follows: The equivalent diameter of the groove or protrusion on the bottom wall of the inner pot is D, and the thickness of the inner metal layer 323 is H1, where the equivalent diameter D satisfies the following relationship: 0.08≦D / H1≦3.

[0068] The ratio of the equivalent diameter D to the thickness H1 indicates the number of corresponding grooves per unit thickness. If the number of grooves per unit thickness is too large, the flotation rate per unit thickness will be too high. If the heat per unit thickness is constant, a high flotation rate will result in lower heat conduction efficiency. If the number of grooves per unit thickness is too small, the flotation rate per unit thickness will be too low. If the rice is placed close to the wall of the pot, it will receive more heat and be more likely to stick. Therefore, in a specific embodiment of the present application, the number of grooves per unit thickness is greater than or equal to 0.08 and less than or equal to 3, thereby combining low heat transfer efficiency and the problem of sticking.

[0069] In Examples 1 and 2 and some other specific embodiments of the present application, the specific value of D / H1 may further be 0.08, 0.53, 0.98, 1.43, 1.88, 2.33, 2.78, or 3. As shown in Figures 4-1 and 5-1, the equivalent diameter D is 455.2 μm, H1 is 428.1 μm, and the ratio is 1.06.

[0070] The deformation of the adhesive array 33 between the side wall of the inner kettle and the bottom wall of the inner kettle should be within a predetermined ratio range, and the predetermined range further includes: In some specific embodiments of the present application, the stretched grooves or protrusions of the anti-adhesive array 33 are located on the side wall, and the maximum diameter of the grooves on the side wall of the inner pot after deformation is 1620 μm or less. As shown in FIG. 5-2, the maximum diameter of the grooves after deformation is 585.9 μm.

[0071] The width of a typical grain of rice is about 2mm, and its water absorption expansion rate is about 1.5 to 2 times, so the size width of the rice after absorbing water is about 3mm or more. In order to fulfill the non-stick effect of the rice and prevent the rice grains from getting stuck, the maximum diameter after deformation is no more than 1620μm. After being pulled, the groove will be larger than its original size and may even exceed the size of the rice grain, so the rice grains will easily get stuck in the deformed groove. As mentioned above, the inner pot manufactured in the axial direction is generally longer and generally shorter in the circumferential direction, so slits are easily formed in the deformed groove. Based on this, when the deformation size exceeds the upper limit, the rice grains will easily get stuck, and the rice grains stuck in the groove will be heated three-dimensionally, and the rice starch will easily burn and cause sticking problems.

[0072] The grooves or protrusions of the anti-adhesive array 33 are located on the side wall, and the minimum diameter of the side wall of the inner pot after deformation is 50 μm or more. As shown in Figure 5-2, the minimum diameter of the grooves after deformation is 324.6 μm.

[0073] To achieve the non-stick effect, a minimum actual value is required after the lateral diameter decreases, for example, above 100 μm. If the actual value is less than this value, the groove will be too narrow to achieve the anti-stick effect, the formed slit will be difficult to clean, dirt will accumulate inside it, affecting food hygiene, the inner surface of the inner pot will be easily blackened, and there will be a strange smell and the smell will be easily transferred.

[0074] The maximum value of the equivalent diameter D of the grooves or protrusions on the bottom wall of the inner pot is 900 μm or less, and the minimum value is 100 μm or more. In this way, during the process of cooking rice using the cookware, the deformation of the grooves or protrusions of the anti-stick array 33 on the side wall of the inner pot is neither too large nor too small, but within a reasonable range, which ensures the non-stick effect of the inner pot.

[0075] In the examples of the present application, the thickness of the metal plate is 1 to 5 mm, and the thickness variation of the plate is controlled to about ±10%, for example, 3 mm, and the thickest point after being stretched is 3.32 mm.

[0076] As the thickness of the metal plate increases, the mass also increases, and the thickness of the outer metal layer 321 also increases accordingly, thereby improving the protection ability of the inner pot. In some specific embodiments of the present application, the ratio of the thickness of the outer metal layer 321 to the thickness of the metal plate is 0.2 to 0.4. Specifically, the ratio is 0.2, 0.25, 0.3, 0.35, or 0.4. The ratio of the bottom wall of the inner pot in Figure 4-1 is 464.5 / 1243=0.37, and the ratio of the side wall of the inner pot in Figure 4-2 is 463.6 / 1295=0.36.

[0077] As the thickness of the metal plate increases, the inner metal layer 323 also increases in thickness, but is thinner than the outer metal layer 321, and the ratio of the inner metal layer 323 to the thickness of the metal plate is 0.1 to 0.4, specifically 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4. The ratio of the bottom wall of the inner pot in Figure 4-1 is 428.1 / 1243 = 0.34, and the ratio of the side wall of the inner pot in Figure 4-2 is 463.6 / 1295 = 0.36.

[0078] Generally, the thicker the metal plate, the larger the capacity and therefore the higher the thermal conductivity requirements. In this case, the heat spreader 322 is usually thicker, and the ratio of the heat spreader 322 to the thickness of the metal plate is 0.2 to 0.7. Specifically, this ratio is 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, or 0.65. The ratio of the bottom wall of the inner pot in Figure 4-1 is 355.2 / 1243 = 0.28, and the ratio of the side wall of the inner pot in Figure 4-2 is 372.7 / 1295 = 0.28.

[0079] For the 1.5 mm metal plate, the thicknesses of the internal metal layer 323, the heat spreader layer 322, and the external metal layer 321 are 0.5 mm, 0.5 mm, and 0.5 mm, respectively, and for the 3 mm metal plate, the thicknesses of the internal metal layer 323, the heat spreader layer, and the external metal layer 321 are 0.8 mm, 1.6 mm, and 0.6 mm, respectively.

[0080] In some specific embodiments of the present application, the grooves in the anti-stick array 33 are separate, independent recesses that are not connected to each other, and the anti-stick array 33 in the middle of the inner pot bottom wall covers the temperature measuring device. Because the grooves are separate, independent recesses that are not connected to each other, the grooves have a certain water retention capacity, can maintain a water film, and have non-stick properties. The anti-stick array 33 in the middle of the inner pot bottom wall covers the temperature measuring device, ensuring that the location where the temperature measuring device is installed is approximately horizontal, ensuring temperature measurement accuracy. Therefore, the inner pot wall is the inner pot bottom wall, and the deformation of the anti-stick array 33 on this wall is small, so its size can be used as the origin of the preliminary axial size and preliminary circumferential size before deformation. To determine the size of the groove before deformation of the manufactured inner pot, for example, obtain the size of the inner pot side wall and then obtain the size of the groove covering the temperature measuring device. Then, compare the two to obtain the desired data.

[0081] In some embodiments of the present application, the grooves have a basic shape, such as a circle, a hexagon, a square, a rectangle, etc., the arrangement of the grooves in the inner pot is a basic array form, such as a rectangular array, a circular array, etc., and the array form of the grooves and protrusions in the anti-stick array 33 is a rectangular array or a circular array. As can be understood by those skilled in the art from the above-mentioned embodiments, the basic shape of the grooves may be other shapes, the array form may be other shapes, and different shapes and array forms may be freely combined, for example, circular rice slurry grooves may be arranged in a rectangular array form.

[0082] Anything not mentioned in this application can be realized by using or referring to the prior art.

[0083] Each embodiment in this specification is described in a progressive manner, and reference may be made to similar or similar parts between the embodiments, and each embodiment mainly describes the differences from other embodiments.

[0084] The above is merely an example of the present application and does not limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any amendments, equivalent replacements, improvements, etc. completed within the spirit and principles of the present application should fall within the scope of the claims of the present application. [Explanation of symbols]

[0085] 10 ···Pot body; 105...Heating device; 20 ···Pot lid; 30 ···Inner pot; 31 ··· bottom wall; 32...side wall; 33 ···Anti-adhesive array; 301 ···Cooking cavity; 321 ···Outer metal layer; 322 ···Heating layer; 323...inner metal layer.

Claims

1. A method for manufacturing an inner pot of a non-stick pot, providing a metal plate material having at least an outer metal layer, a heat-soaking layer and an inner metal layer, and performing etching, engraving or pressing on the inner metal layer side to form an anti-adhesive array including a plurality of grooves or protrusions; The method includes the steps of: stretching the metal plate provided with the anti-adhesive array by controlling the stretching rate to manufacture the inner kettle; or stretching the metal plate to form an inner kettle blank by controlling the stretching rate, and then expanding the inner kettle blank by controlling the expansion rate to manufacture the inner kettle; The thickness ratio of the side wall of the manufactured inner pot to the bottom wall of the inner pot is 0.9 to 1.1, and the thickness ratio of the outer metal layer to the inner metal layer is 0.6 to 1.4, so that the grooves or protrusions deformed by tension in the anti-adhesive array meet a predetermined range; The predetermined range includes that the anti-stick array has grooves or protrusions on the side wall that are deformed by tension, and the deformation ratio along the axial direction of the side wall of the inner pot is 1.1 to 1.8 times.

2. The method for manufacturing the inner pot of a non-stick pot as described in claim 1, characterized in that the grooves or protrusions in the anti-stick array that are stretched and deformed are located on the side wall, and the deformation ratio along the circumferential direction of the side wall of the inner pot is 0.5 to 1.01 times.

3. The equivalent diameter of the groove or protrusion on the bottom wall of the inner pot is D, and the thickness of the inner metal layer is H1, and the equivalent diameter D satisfies the following relationship: 0.08≦D / H1≦3 2. The method for manufacturing the inner pot of the non-stick pot according to claim 1.

4. 2. The method for manufacturing the inner pot of a non-stick pot as claimed in claim 1, wherein the grooves or protrusions in the anti-stick array that are deformed by tension are located on the side wall, and the maximum diameter of the grooves on the side wall of the inner pot after deformation is 1620 μm or less.

5. 2. The method for manufacturing the inner pot of a non-stick pot according to claim 1, wherein the grooves or protrusions in the anti-stick array that are stretched and deformed are located on the side wall, and the minimum diameter of the side wall of the inner pot after deformation is 50 μm or more.

6. 2. The method for manufacturing the inner pot of a non-stick pot according to claim 1, wherein the ratio of the thickness of the outer metal layer to the thickness of the metal plate is 0.2 to 0.

4.

7. 2. The method for manufacturing the inner pot of a non-stick pot according to claim 1, wherein the ratio of the thickness of the inner metal layer to the thickness of the metal plate is 0.1 to 0.

4.

8. 2. The method for manufacturing the inner pot of a non-stick pot according to claim 1, wherein the thickness of the heat-soaking layer is in the range of 0.2 to 0.7 relative to the thickness of the metal plate.

9. 2. The method for manufacturing the inner pot of a non-stick pot according to claim 1, wherein the grooves in the anti-stick array are separate recesses that are not connected to each other but are independent of each other, and the adhesive array in the middle of the bottom wall of the inner pot covers the temperature measuring device.

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