JP2016116640A - Pot for cooker and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pot for a cooker and a manufacturing method of the same which do not generate a failure of insertion and run of molten metal in a boundary part of a heating element in a molten metal forging process.SOLUTION: A pot 31 is composed of: a pot base body 21 formed into a container shape by solidifying molten aluminum; and a heating element 1 attached on an outer face of the pot base body 21 in response to solidification of the molten aluminum. The heating element 1 is formed into a ball shape and includes: an iron bottom part 2 not covered with the pot base body 21 on an outer face to be exposed; and an extension part 6 covered with the pot base body 21 on an outer face and extended linearly from an upper peripheral edge being a tip of the iron bottom part 2.SELECTED DRAWING: Figure 1

Description

  The present invention is applied to various cookers such as rice cookers, and relates to a cooker pan manufactured by molten metal forging and a method for manufacturing the same.

  The cooker pan manufactured by molten metal forging needs to heat the pan with a heating coil, and is composed of a heating element made of a stainless steel drawn iron sprayed on the inner surface and a pan base with good heat conductivity such as aluminum. . A method for manufacturing a cooking pot, for example, is disclosed in Patent Documents 1 and 2 and the like, but in a state where a heating element sprayed with iron is set in a female mold, the pot base dissolved in the female mold is Pour aluminum as a base material, fit a male mold corresponding to the internal shape of the pan, solidify the aluminum while pressing with a press, forming a pan that combines the pan base and the heating element . Hereinafter, this series of manufacturing processes is referred to as a molten metal forging process.

  FIG. 6 is a cross-sectional view of the main part when the conventional heating element 1 is set in the female mold 101. FIG. 7 is an enlarged view of part A of FIG. In each of these drawings, the female mold 101 has a cavity surface 102 which is a concave inner surface corresponding to the outer shape of a pan (not shown here), and a stepped corner is provided in the middle of the cavity surface 102. A portion 103 is formed around. On the other hand, the heating element 1 has a bottomed ball shape with an open top, an iron bottom 2 that generates heat by an alternating magnetic field from a heating coil (not shown), and a flange that is bent outward at the upper end of the heating element 1. 3. Then, the heating element 1 is set in a suspended state on the female mold 101 by placing the flange portion 3 on the corner portion 103. At this time, a predetermined retraction gap 111 is formed between the outer surface of the heating element 1 and the cavity surface 102 of the female die 101 to enable the heating element 1 to be retracted during subsequent pressurization.

  In the molten metal forging process, the boundary of the heating element 1 during pressurization with a press is applied so that the molten aluminum does not enter the outer surface of the heating element 1 beyond the boundary part of the heating element 1 located immediately below the flange portion 3. It is necessary to seal the portion in close contact with the female mold 101. In this method, in the molten metal forging process, the heating element 1 is narrowed down by the flange part 3 of the heating element 1 and the corner part 103 of the female die 101, so that the entire circumference is formed between the boundary surface of the heating element 1 and the cavity surface 102. It was to seal over.

  FIG. 8 is an enlarged view of a portion B in FIG. 6 for explaining a conventionally considered sealing structure between the heating element 1 and the female die 101. In the “before pressurization” state shown in FIG. 5A, the flange portion 3 of the heating element 1 is placed on the surface of the corner portion 103 of the female mold 101 without a gap. Thereafter, when molten aluminum is poured into the female mold 101 on which the heating element 1 is set, and a male mold (not shown) is fitted and pressed with a press, the space between the boundary surface of the heating element 1 and the cavity surface 102 is formed. If it is completely sealed over the entire circumference, the molten aluminum does not protrude below the outer surface of the boundary portion of the heating element 1.

  However, in the “after pressurization” state shown in FIG. 8B, the flange portion 3 is raised in the pressurizing direction as the heating element 1 is pulled in the direction of the arrow S1 when pressurizing with the press. Between the boundary portion 4 of the heating element 1 and the cavity surface 102 of the female mold 101 is not completely sealed, and molten aluminum enters the gap from the direction of the arrow S2, and the molten metal is located below the boundary surface 4. Boundary burrs of aluminum R occur.

  At the beginning of the development of the above-described molten metal forging process, the inner surface of the pan was cut and then painted on the inner surface and the outer surface of the pan. Even if it spilled around the outside, it didn't matter much. However, in recent years, in order to improve the design of the pan, since the product specifications with the base of the heating element 1 as the exterior surface have become mainstream, such wraparound of aluminum has become impossible. In the boundary portion 4 of the aluminum, the protruding aluminum was cut.

JP-A-8-52064 JP-A-8-52065

  As for the wrapping of the base material to the outer surface of the heating element 1 described above, a large amount of the base material that wraps around is called “poor hot water bottle defect”, and a small one is called “boundary burr defect”. In addition, a phenomenon in which the base material does not spread until the entire circumference of the boundary surface 4 of the heat generating element 1 and a gap is formed between the heat generating element 1 and the base material is referred to as “poor hot water”.

  FIG. 9 is a photograph of the appearance of the pan 31 in which “poor hot water” has occurred. In FIG. 9, the hot water defective portion F1 of the pan base 21 protruding from the boundary portion 4 of the heating element 1 can be confirmed. The hot water bottle means that the size of the hot water around the outer surface of the heating element 1 at the boundary portion 4 (that is, the distance from the boundary portion 4 to the burr tip of the pan base 21) is 5 mm or more. FIG. 10 is a photograph of the appearance of the pan 31 in which “boundary burr failure” has occurred. In this figure, the boundary burr defective portion F2 of the pan base 21 protruding from the boundary portion 4 of the heating element 1 can be confirmed. The boundary burr indicates that the size of the hot water around the outer surface of the heating element 1 at the boundary 4 is less than 5 mm. FIG. 11 is a photograph of the appearance of the pan 31 that has caused “poor hot water”. In FIG. 11, the pan base 21 does not go around the entire circumference of the boundary portion 4 of the heating element 1 and has a shape in which a hole is opened. A hot water defect portion F3 can be confirmed.

  In the case of “poor hot water bath” or “boundary burr defect”, it is necessary to cut the protruding portion of the pan base 21 at the boundary portion 4 of the heating element 1 as a finishing process of the pan. Possible cutting failure. Therefore, it was considered that the best method for eliminating the defective cutting at the boundary portion 4 of the heating element 1 is to eliminate the cutting process itself. In order to realize this, eradication of “poor hot water bottle defects” including “boundary flash defect” and “poor water bath defects” is an essential condition.

  The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a cooking pot that does not cause defects due to a hot water bottle or a hot water at the boundary of a heating element in a molten metal forging process and a method for manufacturing the same. There is.

  The present invention is for a cooking device comprising: a pan base formed into a container shape by solidifying a molten heat conductive material; and a heating element attached to the outer surface of the pan base as the heat conductive material is solidified. In the pan, the heating element is ball-shaped, and has a side wall that is exposed without being covered by the pan base, and an extension that is covered by the pan base and extends linearly from the tip of the side wall. It is characterized by that.

  The present invention also includes a step of preparing a female mold having a stepped corner on the inner surface, a step of preparing a ball-shaped heating element having an extension extending linearly from the tip of the side wall, and the corner A step of setting the heating element on the inner surface of the female mold, a step of pouring molten heat conductive material into the female mold, and A step of fitting and pressing a male mold to deform the heating element so as not to bend at the corners, solidifying the heat conductive material to form a container-shaped pan base, and the heat conductive material The step of attaching the heating element to the outer surface of the pan base so that the outer surface of the side wall is not covered with the pan base and the pan base is covered with the outer surface of the extension. And a method for manufacturing a cooking pot.

  According to the first and second aspects of the present invention, the ball-like heat generation is performed in the course of the molten metal forging step by forming a linearly extending portion instead of bending the flange at the front end of the side wall of the heating element. No matter how the body is tilted with respect to the female mold, a cooker pan that does not cause defects due to a molten metal hot water bottle or hot water at the boundary between the side wall and the extension is obtained. be able to.

The vertical end view and the principal part enlarged view are each shown about the pan of the completion state in one Embodiment of this invention. As a comparison with FIG. 1, a vertical end view and an enlarged view of a main part of a pan in a conventional completed state are shown. FIG. 7 is an enlarged view of a portion B in FIG. 6 for explaining an actual seal structure between a heating element and a female die. In this embodiment, it is a figure which shows the principal part end surface shape of the heat generating body before setting to a metal mold | die. It is a photograph which shows the principal part cross-sectional shape of the pan after a molten metal forging process. It is principal part sectional drawing when the conventional heat generating body is set to the female metal mold | die. It is the figure which expanded the A section of FIG. 6 same as the above. FIG. 7 is an enlarged view of a portion B in FIG. 6 for explaining a conventionally considered sealing structure between a heating element and a female mold. It is a photograph of a pan showing an example of “poor hot water bath”. It is a photograph of a pan showing an example of “boundary burr defect”. It is a photograph of a pan showing an example of “poor hot water”.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a pot used in a rice cooker that is a cooking device. Note that portions common to the conventional example and the present embodiment will be described using basically the same reference numerals.

  FIG. 1 shows a vertical end view on the right side and an enlarged view of a portion surrounded by a square with respect to the symmetry axis P of the pan 31 of the present embodiment. The pan 31 in a completed state shown in FIG. 1 is formed through the above-described molten metal forging process, and has a bottomed container shape with an open upper surface so as to accommodate a predetermined amount of rice to be cooked such as rice or water. It is comprised by the pan base 21 and the heat generating body 1 which closely_joins from the outer bottom face part of the pan base | substrate 21 to an outer peripheral surface part. The pan base 21 is obtained by solidifying a molten heat conductive material such as aluminum, and forms the entire inner surface and upper outer surface of the completed pan 31. Further, as the heat conductive material to be the pan base 21 is solidified, the heating element 1 attached to the outer surface of the pan base 21 is made of a material that is induction-heated, such as iron or stainless steel, and the outer surface of the finished pan 31. Form the lower side. Here, the configuration other than the pan 31 is not shown, but the pan 31 into which the rice is to be cooked is attached to the main body of the rice cooker, the top opening of the pan 31 is closed with a lid, and heating is started by input from the operation unit. When instructed, a high-frequency current flows through the heating coil arranged in the rice cooker body, the heating element 1 generates heat by the alternating magnetic field generated from the heating coil, is conducted to the pot base 21, and the cooked rice accommodated in the pot 31 is heated. The

  As shown in FIG. 1, the pan 31 as a whole has a bottom wall portion 33 that can be placed on the floor surface, a peripheral side wall portion 34 that rises from the outer peripheral edge of the bottom wall portion 33, and an upper peripheral edge of the peripheral side wall portion 34. The upper wall portion 35 reaching the upper end of the pan 31 and an annular flange-shaped blade portion 36 extending in the outer peripheral direction from the upper outer surface of the peripheral side wall portion 34, and in particular, the upper wall portion 35 is shrunk and the peripheral side wall By giving the side surface of the part 34 roundness, strong heat convection is caused to the cooked rice, heat is quickly transmitted to the center, and the pan 31 is formed in a shape that can maintain a high temperature.

  The heating element 1 extends linearly from the bowl-shaped iron bottom 2 disposed from the bottom wall 33 of the pan 31 to the lower side of the peripheral side wall 34 and the upper peripheral edge that is the tip of the iron bottom 2. It is comprised by the extension part 6 which reaches the upper periphery used as the front-end | tip of 1. As shown in FIG. Among them, the iron bottom portion 2 of the heating element 1 serves as the bottom wall of the pan 31 and the side wall rising from the outer peripheral edge of the bottom wall, both of which the outer surface is not covered with the pan base 21. Is formed. On the other hand, the extended portion 6 of the heating element 1 is covered with the pot base 21 and the outer surface of the extension 1 is slightly expanded in the outer peripheral direction of the pot 31, and the bent portion is not formed as it is. It extends continuously. Therefore, it can be said that the boundary portion 4 of the heating element 1 here is a portion that becomes a boundary between the iron bottom portion 2 and the extension portion 6.

  For comparison, FIG. 2 shows a conventional completed pan 31 described in the background art. In the same figure, a vertical sectional view on the right side and an enlarged view of a portion surrounded by a square are also illustrated here with the symmetry axis P of the pot 31 as a boundary. Explaining the difference from the pan 31 of the present embodiment shown in FIG. 1, the conventional pan base 21 is provided with an annular flange 37 in the outer peripheral direction from the upper peripheral edge of the upper wall portion 35 in place of the blade portion 36. Yes. However, this relates to the outer shape of the pan 31 and can be appropriately changed, and is not directly related to the present invention. What is important is that, in the completed pan 31, instead of the flange portion 3 bent non-linearly at the upper part of the conventional heating element 1, an extension portion 6 that is not bent linearly is formed. That is.

  By the way, conventionally, in this kind of pan 31, the cause of occurrence of “poor hot water bath” and “boundary burr defect” in the molten metal forging process is considered to be as described with reference to FIG. 8. . However, the present inventors have found that the object of the present invention can be achieved as a result of correctly elucidating the mechanism of occurrence of such a defect and intensively studying how the defect can be stopped therefrom. Details will be described below.

  FIG. 3 is a view for explaining the seal structure between the heating element 1 and the female die 101, which has been clarified by the present inventors. FIG. 3 is an enlarged view of the portion B in FIG. 6 corresponding to FIG. is there. As shown in “Before pressurization” in FIG. 5A, in the actual melt forging process, when the heating element 1 is set on the female die 101, the lower surface of the flange portion 3 and the corner portion 103 of the female die 101 are formed. A slight gap 121 is formed between the upper surface. This is because the ball-shaped heating element 1 is tilted with respect to the female mold 101 and is detached from the original seal portion of the female mold 101. Therefore, the heating element 1 has the predetermined retraction gap shown in FIG. 7 in a state where the upper outer surface of the iron bottom 2 below the flange 3 and the side surface below the corner 103 of the female die 101 are in contact with each other. 111 is set in the female mold 101.

  Thereafter, when molten aluminum is poured into the female mold 101 on which the heating element 1 is set, a small amount of molten aluminum R also enters the gap 121 from the direction of the arrow S3 shown in FIG. The molten aluminum R that has reached the gap 121 adheres to the outer surface of the shoulder R portion 122 that is the bent base end of the flange portion 3 and solidifies before the other molten aluminum.

  Next, when a male mold (not shown) is fitted and pressed with a press, the state is “after pressurization” shown in FIG. When the heating element 1 is pulled in the direction of the arrow S1 during pressurization with the press, the shoulder R part 122 hits the corner part 103 and the flange part 3 is deformed in the pressing direction. The molten aluminum R adhered to and solidified is drawn together with the heating element 1 and protrudes as a boundary burr below the boundary portion 4. This is presumed to be the actual occurrence mechanism of “poor hot water bath defect” and “boundary burr defect”.

  Further, in the conventional melt forging process described above, the heating element 1 having the flange portion 3 is set in the female die 101, so that the outer end surface of the flange portion 3 and the female die are shown in FIG. There are few gaps between the cavity surface 102 of 101. In particular, when the heating element 1 is inclined outward with respect to the female mold 101, the gap becomes extremely small, and a very small amount of molten aluminum enters the gap 121 on the lower surface side of the flange portion 3 and solidifies first. The molten aluminum does not turn around the entire gap 121. For this reason, the pan base 21 does not wrap around the entire periphery of the boundary portion 4 of the heating element 1 after pressurization with a press, resulting in “poor hot water”.

  That is, when the heating element 1 is inclined inward with respect to the female mold 101 in a conventional manner, the flange portion 3 is bent outwardly from the upper end of the ball-shaped heating element 1. The gap between the outer end surface of the flange portion 3 and the cavity surface 102 of the female mold 101 is widened, and “poor hot water” and “boundary burr defect” are likely to occur. When the body 1 is tilted to the outside, the gap is narrowed, and the mechanism leading to the actual defect that “poor hot water” is likely to occur has been elucidated. Therefore, the present inventors have taken the following four measures to prevent these defects from occurring even when the heating element 1 is tilted and set on the female mold 101, as shown in FIG. The present inventors have found a method for producing a round pot-shaped pan 31 without performing a cutting process after a molten metal forging process.

  As a first countermeasure, the seal portion diameter (radius) D1 of the heating element 1 located at the uppermost portion of the iron bottom portion 2 and in close contact with the cavity surface 102 of the female die 101 in the molten metal forging process is smaller than that of the conventional one. To do. As an example, in the conventional pan 31 shown in FIG. 2, the seal portion diameter D1 of the heating element 1 is 99.8 mm, whereas in the pan 31 of this embodiment shown in FIG. The diameter D1 is 99.5 mm. In addition, the seal portion diameter D1 of the heating element 1 before the molten metal forging step is 100 mm. In other words, at the portion facing the seal portion (that is, the boundary portion 4) of the heating element 1, the radial seal of the heating element 1 is strengthened by changing the dimensions of the female die 101, so It can be used as a countermeasure against “burr defects”.

  As a second countermeasure, instead of the conventional flange portion 3, the heating element 1 having a shape in which the extension portion 6 is linearly extended from the upper peripheral edge of the iron bottom portion 2 is used. By eliminating the narrowing of the flange portion 3 in the molten metal forging process, it is possible to take measures against not only “poor hot water bath” and “boundary burr defect” but also “poor hot water runoff”.

  As a third countermeasure, the height dimension t1 of the extension portion 6 in the present embodiment is made larger than the height dimension t1 of the conventional flange portion 3, and the height dimension of the heating element 1 is increased. As an example, the height dimension t1 of the flange portion 3 shown in FIG. 2 is 0.7 mm, whereas the height dimension t1 of the extension portion 6 shown in FIG. 1 is 3.5 mm. This can be a countermeasure against “poor hot water bottle defects” and “boundary burr defect” due to the inclination of the heating element 1.

  As a fourth countermeasure, the height dimension t2 from the bottom surface of the pan 31 to the seal portion is lowered. As an example, the height dimension t2 from the bottom surface of the pot 31 shown in FIG. 2 to the seal portion is 57.5 mm, whereas the height dimension t2 from the bottom surface of the pot 31 shown in FIG. It is 56.5 mm. This can be a countermeasure against “poor hot water bottle defects” and “boundary burr defect” due to the inclination of the heating element 1.

  The pan 31 in a completed state shown in FIG. 1 is manufactured by a molten metal forging process as in the prior art. First, a female die 101 having a stepped corner 103 formed around a cavity surface 102 serving as a concave inner surface, and an extended portion 6 extending linearly from the upper peripheral edge of the iron bottom 2 were formed around. A ball-shaped heating element 1 is prepared. FIG. 4 shows the main part shape of the heating element 1 before being set in the female mold 101.

  Next, when the prepared heating element 1 is set (attached) to the cavity surface 102 of the female die 101, the elastic force in the radial direction of the heating element 1 acts and the iron below the extension 6 of the heating element 1 is applied. The upper outer surface of the bottom portion 2 is in a state where the side surface below the corner portion 103 of the female mold 101 is pressed and sealed. At this time, the entire extension portion 6 is disposed so as to protrude above the corner portion 103, and the predetermined retraction gap 111 shown in FIG. 7 is provided between the outer bottom surface of the iron bottom portion 2 and the cavity surface 102. As a result, the heating element 1 is held in a state of floating on the female die 101.

  Thereafter, molten aluminum is poured into the female mold 101 on which the heating element 1 is set. Since the extension 6 of the heating element 1 protrudes above the corner 103 of the female mold 101 in advance, not only the inner surface but also the outer surface of the extension 6 is covered with molten aluminum. Further, by extending the extension 6 in a straight line, the phenomenon that the molten aluminum solidifies first outside the extension 6 is also avoided.

  Next, a male mold (not shown) is fitted into the female mold 101 into which the molten aluminum is poured, and is pressed with a press. Due to this pressurization, the heating element 1 is pulled from the above-described floating state while being regulated by the female die 101 in the same state as the hydraulic throttle, and the heating element 1 is not bent at the corner 103 and the cavity surface is bent. It is deformed until it has the same shape as 102. Again, due to the elastic force in the radial direction of the heating element 1, the sealing state between the heating element 1 and the cavity surface 102 of the female die 101 is maintained, and below the sealing portion (which eventually becomes the boundary portion 4). Prevents molten aluminum from protruding.

  Thereafter, the molten aluminum is solidified to form a container-shaped pan base 21 and, along with the solidification of the molten aluminum, the heating element 1 is tightly coupled to the outer surface of the pan base 21 to complete a series of molten forging processes. To do. As a result, the pan base 21 is not covered at all on the outer surface of the iron bottom 2 with the boundary portion 4 as a boundary, and the pan base 21 is covered on the outer surface of the extension 6 without any gap. Thus, the pan 31 in a completed state that does not require cutting of the boundary portion 4 can be obtained. In FIG. 5, the principal part cross section of the actual pan 31 after a molten metal forging process is shown as a photograph.

  As described above, the pan 31 in a completed state according to the present embodiment includes a pan base 21 that is formed into a container shape by solidifying molten aluminum that is a melted heat conduction material, and the pan base 21 as the molten aluminum is solidified. The heating element 1 is attached to the outer surface of the heater. The heating element 1 is formed in a ball shape without a flange at the upper end, the iron bottom 2 as a side wall that is exposed without the outer surface being covered by the pot base 21, and the outer surface is covered by the pot base 21. And an extension portion 6 that extends in a straight line from the upper peripheral edge, which is the tip of the bottom portion 2, and is formed.

  In this case, the ball-shaped heating element 1 is not deformed at the tip of the iron bottom part 2 of the heating element 1 but is formed into a linearly extending portion 6 so that the ball-shaped heating element 1 is in the middle of the molten metal forging process. No matter how the tilt is set with respect to the mold 101, a pan 31 is obtained that does not cause a defect due to a molten metal hot-water bottle or hot water at the boundary portion 4 that is the boundary between the iron bottom portion 2 and the extension portion 6. be able to.

  In addition, the same effect is obtained by preparing a female mold 101 in which stepped corners 103 are formed around the cavity surface 102 which is the inner surface, and extending the extension 6 straight from the tip of the iron bottom 2 serving as a side wall. The heating element 1 is set on the inner surface of the female die 101 with the step of preparing the ball-shaped heating element 1 extending in a circular shape and the protruding portion 6 protruding above the corner 103. A step of pouring molten aluminum as a heat conduction material into the female mold 101, a male mold (not shown) is fitted into the female mold 101 and pressed, and the heating element 1 is not bent at the corner 103. The molten aluminum is solidified to form a container-like pan base 21 and the outer surface of the iron bottom 2 is not covered with the pan base 21 as the molten aluminum is solidified. , The outer surface of the extension portion 6 as pan base 21 is covered, a step of attaching a heating element 1 to the outer surface of the pan base body 21, also realized by the production method of the pan 31 made.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, although the rice cooker pot has been described as an example in the above-described embodiment, the technical idea of the above-described embodiment may be applied to a cooker pot that accommodates an object to be cooked in various cookers other than the rice cooker. Moreover, the dimension of each part is an example to the last, and this invention is not limited to the dimension. In addition, the outer shape of the pan may be changed as appropriate.

1 Heating element 2 Iron bottom (side wall)
6 Extension part 21 Pan base 31 Pan 101 Female mold 102 Cavity surface 103 Corner

Claims (2)

A pan base formed into a container shape by solidifying the molten heat conducting material;
With the heat conduction material solidified, a heating element attached to the outer surface of the pot base,
The heating element has a ball shape, and has a side wall that is exposed without being covered with the pan base, and an extension that is covered with the pan base and that extends linearly from the tip of the side wall. Cooking pot. Preparing a female mold having stepped corners on the inner surface;
Preparing a ball-shaped heating element having an extension extending linearly from the tip of the side wall;
Setting the heating element on the inner surface of the female mold in a state in which the extension portion protrudes from the corner portion;
Pouring a molten heat conducting material into the female mold;
Fitting a male mold to the female mold and applying pressure to deform the heating element so as not to bend at the corner;
The heat conductive material is solidified to form a container-shaped pot base, and with the solidification of the heat conductive material, the outer surface of the side wall is not covered with the pot base, and the outer surface of the extension portion is the pot. Attaching the heating element to the outer surface of the pan base such that the base is covered;
The manufacturing method of the pan for cookers characterized by comprising.