Manufacturing method for mixing tube components of a stove burner

Abstract

To provide a manufacturing method of a mixing pipe formation member of a cooking stove burner which enables a cutout-like wall part useful for interference avoidance to be formed properly while preventing a protrusion part from being formed at an upper wall part of a predetermined expansion part when processing is performed at a metal plate to manufacture the mixing pipe formation member of the cooking stove burner.SOLUTION: A manufacturing method of a mixing pipe formation member MU of a cooking stove burner has: an expansion part formation step in which deep drawing processing is performed on a metal plate 3A prepared as a raw material to form a predetermined expansion part 4; and a cutout-like wall part formation step in which a part in a circumferential direction of an upper part of a peripheral wall part 40 of the expansion part 4 is formed into a cutout-like wall part 45 inclined at an inclination angle closer to horizontal than other portions of the peripheral wall part 40 and having a cutout shape in a side view. When the expansion part formation step is performed, the step includes a step in which a punch in which a cutout part 70 corresponding to the cutout-like wall part 45 is formed is used as a punch 7, and a die which does not correspond to the cutout part 70 of the punch 7 and is formed in a cylindrical shape is used as a die 8.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a mixing tube component of a stove burner.

Background Art

[0002] As described in Patent Documents 1 to 3, for example, a stove burner generally has a configuration including a mixing tube. The mixing tube is a member for guiding a mixture of fuel gas and air to a plurality of flame holes provided in a burner cap, and usually, the burner cap is placed on the upper side of this mixing tube. Such a mixing tube of a stove burner is, for example, made by aluminum die-casting, etc., but this results in a high manufacturing cost. As a means for reducing the manufacturing cost of the mixing tube, for example, a means of forming a component of the mixing tube by subjecting a metal plate to press working can be considered.

[0003] However, when the above means is adopted, there are problems to be improved as described below.

[0004] That is, when forming a component of the mixing tube using a metal plate, it is conceivable to form a part of this metal plate as an upwardly standing bulging portion, and place the burner cap on the upper wall portion of this bulging portion. In this case, the ignition plug is arranged beside the bulging portion so as to approach the burner cap. However, if the ignition plug is inclined, for example, to approach the flame hole of the burner cap, there is a risk of interference between the upper part of the peripheral wall portion of the bulging portion and the ignition plug. As a means for eliminating this risk, it is conceivable to form a side-view notch-shaped wall portion (notch-shaped wall portion) on the upper part of the peripheral wall portion of the bulging portion. However, when such a notch-shaped wall portion is provided, there is a risk of forming a raised portion on the upper wall portion of the bulging portion (see Comparative Example 1 described later with reference to FIG. 11). In this case, when placing the burner cap on the upper wall portion of the bulging portion, the raised portion may become an obstacle, and there is a risk that it may be difficult to set the burner cap in a horizontal posture.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2001-21147 [Patent Document 2] Patent No. 3739915 [Patent Document 3] Japanese Patent Publication No. 2019-27669 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention was conceived under the circumstances described above, and its objective is to provide a method for manufacturing a stove burner mixing tube component that, when manufacturing a stove burner mixing tube component by processing a metal plate, can appropriately form a notched wall portion on the peripheral wall portion of a bulge portion, while preventing the formation of a raised portion on the upper wall portion of a predetermined bulge portion, in order to avoid interference and the like. [Means for solving the problem]

[0007] To solve the above problems, the present invention employs the following technical measures.

[0008] The method for manufacturing a mixing tube component of a stove burner provided by the present invention involves deep drawing a metal sheet as a raw material using a punch and die, and from the plate-like region of the metal sheet upward A method for manufacturing a mixing tube component of a stove burner, comprising: a bulge forming step of forming a bulge having a cylindrical peripheral wall portion standing upright in a certain direction and an upper wall portion connected to the upper part of the peripheral wall portion; and a notched wall portion forming a notched wall portion in which a part of the circumferential direction of the upper part of the peripheral wall portion is notched in side view, characterized in that, when executing the bulge forming step, the punch used is one in which a notch portion corresponding to the notched wall portion is formed, and the die used is one that is cylindrical and does not correspond to the notch portion of the punch.

[0009] With this configuration, it is possible to manufacture a mixing tube component in which a notched wall portion, which is notched in side view, is formed on the upper part of the peripheral wall portion of the bulge. Therefore, for example, a burner cap can be placed on the upper side of the bulge, and a spark plug can be placed close to the side of the bulge, and the notched wall portion can be used to avoid interference with (or close proximity to) the spark plug. In addition to these effects, the following further effects can be obtained. In other words, during the bulge formation process, a punch with a notch corresponding to the notched wall portion is used, and a cylindrical die that does not correspond to the notch portion is used. This allows for a partially recessed area at the location where the notched wall portion is formed, while minimizing the generation of large loads and stresses in that area. According to the present invention, it is not necessary to form the notched wall portion by pressing the peripheral wall portion of the bulge portion from the outside, and it is possible to prevent the formation of a raised portion on the upper wall portion of the bulge portion that would result from the formation of the notched wall portion. This is preferable when, for example, a burner cap is placed on the upper wall portion of the bulge portion in a horizontal position.

[0010] In the present invention, preferably, the deep drawing process in the bulge formation step is performed multiple times, and each time it is performed, the size of the bulge is changed to approach the final target size, and at least during the final deep drawing, a punch with the notch formed therein is used as the punch.

[0011] With this configuration, it is possible to finish the entire bulge to the desired final target size while avoiding, as much as possible, the generation of large stresses in each part of the bulge. Furthermore, at the stage when the final deep drawing process is completed, a region corresponding to the punch notch can be appropriately formed in the bulge.

[0012] In the present invention, preferably, the notched wall forming step is performed after the bulge forming step, and a punch having the notch formed therein is used as the punch, and a die having a projection corresponding to the notch formed therein is used as the die.

[0013] With this configuration, the notched wall portion provided in the bulging section can be appropriately finished to the desired final target size.

[0014] In the present invention, preferably, after the bulge formation step, a burring hole formation step is further included in which a burring hole is formed in the upper wall portion, in which a cylindrical burring portion projecting downward is located at the periphery. Furthermore, as a step performed before the burring hole formation step, a step pressing step is further included in which a downwardly convex and upwardly concave stepped pressing portion is formed in the central region of the upper wall portion of the bulge portion, and a pilot hole is provided in the stepped pressing portion, which has a smaller diameter than the stepped pressing portion and the burring hole. In the burring hole formation step, the burring hole is provided in the stepped pressing portion, and a part of the stepped pressing portion is formed as the burring portion.

[0015] With this configuration, even if the upper wall portion of the bulge of the manufactured mixing tube component is When a burner cap is placed on top, the burner ring hole can be appropriately used as a cylindrical portion provided in the burner cap, or as a hole through which a temperature sensor or the like is inserted. On the other hand, since the burring portion of the burring hole is formed using a part of the stepped recess formed on the upper wall of the bulging portion, it is possible to suppress thinning of the burring portion and make it less prone to cracking.

[0016] Other features and advantages of the present invention will become more apparent from the description of embodiments of the invention given below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0017] [Figure 1] (a) is a schematic cross-sectional view of a main part showing an example of a convector burner. Among the pair of upper and lower mixing tube constituent members of the convector burner shown in this figure, the upper mixing tube constituent member corresponds to an example of a manufacturing target of the manufacturing method according to the present invention, and (b) is a cross-sectional view taken along the line Ib-Ib of (a). [Figure 2] It is a schematic perspective view of a pair of upper and lower mixing tube constituent members of the convector burner shown in FIG. 1. [Figure 3] (a) is a cross-sectional view of the upper mixing tube constituent member shown in FIGS. 1 and 2, and (b) is a cross-sectional view taken along the line IIIb-IIIb of (a). [Figure 4] (a) is a cross-sectional view of the lower mixing tube constituent member shown in FIGS. 1 and 2, (b) is a plan view of (a), and (c) is a cross-sectional view of a main part showing an example of a deep drawing state using a punch and a die of (a). [Figure 5] An example of the first step in manufacturing a mixing tube constituent member by the manufacturing method of the present invention is shown. (a) is a perspective view, and (b) is a cross-sectional view thereof. [Figure 6] An example of the second step in manufacturing a mixing tube constituent member by the manufacturing method of the present invention is shown. (a) is a perspective view, (b) is a cross-sectional view thereof, (c) is a cross-sectional view of a main part showing an example of a deep drawing state using a punch and a die, and (d) is a partially enlarged cross-sectional view of (c). [Figure 7] An example of the third step in manufacturing a mixing tube constituent member by the manufacturing method of the present invention is shown. (a) is a perspective view, (b) is a cross-sectional view thereof, (c) is a cross-sectional view of a main part showing an example of a deep drawing state using a punch and a die, and (d) is a cross-sectional view of a main part showing an open state of the punch and the die shown in (c). [Figure 8] An example of the fourth step in manufacturing a mixing tube constituent member by the manufacturing method of the present invention is shown. (a) is a perspective view, and (b) is a cross-sectional view thereof. [Figure 9] An example of the fifth step in manufacturing a mixing tube constituent member by the manufacturing method of the present invention is shown. (a) is a perspective view, and (b) is a cross-sectional view thereof. [Figure 10] It is a cross-sectional view showing an example of the sixth step in manufacturing a mixing tube constituent member by the manufacturing method of the present invention. [Figure 11] (a) and (b) are cross-sectional views of the main parts showing the proportion to the present invention. [Modes for carrying out the invention]

[0018] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0019] First, for ease of understanding, the configuration of the stove burner B shown in Figure 1 will be explained. In this embodiment, the upper mixing pipe component MU of the stove burner B, which will be described later, is the object of manufacture.

[0020] The stove burner B comprises a mixing tube M, a burner cap 50, a temperature sensor 53, an ignition plug 51, and a gas nozzle 52. The mixing tube M is composed of a pair of upper and lower mixing tube components MU and ML, which combine to form a mixed gas flow path 6. Fuel gas is ejected from the gas nozzle 52 from near the air intake port 60 into the tubular flow path 6a of the mixed gas flow path 6. Consequently, primary air flows into the mixed gas flow path 6 from the air intake port 60, and the mixture of this primary air and the fuel gas travels through the mixed gas flow path 6 and is ultimately guided to a plurality of flame holes 50b provided in the head portion 50a of the burner cap 50. The fuel gas in the mixture that flows out to the outside from these multiple flame holes 50b is ignited by the spark plug 51 and combusted.

[0021] The upper mixing tube component MU is formed by press-forming a metal plate, such as a stainless steel plate. As is clearly shown in Figures 2 and 3, this mixing tube component MU has a bulge 4 and an upward-facing convex portion 30. The bulge 4 has a cylindrical peripheral wall portion 40 that rises upward from the plate-like region 3, and an upper wall portion 41 connected to the upper part of this peripheral wall portion 40, and a burring hole portion 43 is provided in the upper wall portion 41. The upward-facing convex portion 30 has a substantially semicircular cross-section that constitutes the upper wall portion of the tubular flow channel portion 6a and forms a recessed groove portion 30a on its lower surface side.

[0022] The bulge portion 4 functions as a support base for the burner cap 50. The burring hole portion 43 (and the burring hole portion 23 described later) is used as a guide hole for insertion of the cylindrical portion 50c of the burner cap 50 and the temperature sensor 53. There is a gap between the burring portion 44 of the burring hole portion 43 and the cylindrical portion 50c of the burner cap 50, and the air-mixed gas supplied to the second region 61b of the chamber 61 of the air-mixed gas flow path 6, described later, is guided to the flame hole 50b of the burner cap 50 by passing through this gap. A notch portion 49 is formed in part of the burring hole portion 43, which is used for positioning the burner cap 50, etc.

[0023] Furthermore, a notched wall portion 45 is formed on the upper part of the peripheral wall portion 40 of the bulging portion 4, which is notched in side view. This notched wall portion 45 is a part of the upper part of the peripheral wall portion 40 that is partially recessed in a circumferential direction, as if it were cut out in side view. The outer surface of this notched wall portion 45 may be flat or curved. As shown in Figure 1, this notched wall portion 45 serves as a part to avoid interference (or a part to avoid close proximity) between the spark plug 51 and the bulging portion 4.

[0024] The lower mixing tube component ML, like the upper mixing tube component MU, is formed by press-forming a metal plate such as a stainless steel plate. As is clearly shown in Figures 2 and 4, this mixing tube component ML has a bulge 2 and a downward-facing convex portion 10. The bulge 2 has a cylindrical peripheral wall portion 20 that rises upward from the plate-like region 1 and an upper wall portion 21 connected to the upper part of this peripheral wall portion 20, and a burring hole portion 23 is provided in the upper wall portion 21. The downward-facing convex portion 10 has a substantially semicircular cross-section that constitutes the lower wall portion of the tubular flow path portion 6a and forms a recessed groove portion 10a on its upper surface.

[0025] As shown in Figure 1, the bulge portion 2 is fitted into the lower part of the bulge portion 4 of the upper mixing tube component MU, thereby forming a chamber 61 of the mixed gas flow path 6 between the two bulge portions 2 and 4. The chamber 61 includes a first region 61a sandwiched between the peripheral walls 20 and 40 of the two bulge portions 2 and 4, as well as a second region 61b sandwiched between the upper walls 21 and 41 of the two bulge portions 2 and 4. The peripheral wall 20 of the bulge portion 2 has a pair of stepped portions 22 (see Figures 2 and 4) that extend inclined in the vertical direction. Between the two peripheral walls 20 and 40, the portion closer to the tubular flow path 6a than the pair of stepped portions 22 is formed the first region 61a of the chamber 61, and the second region 61b of the chamber 61 and the tubular flow path 6a are in communication via this first region 61a.

[0026] The bulging portion 2 is provided with an upper wall portion 21 connected to the upper part of the peripheral wall portion 20, and a burring hole portion 23 is provided in this upper wall portion 21. This burring hole portion 23 is a portion in which a cylindrical burring portion 24 protrudes downward from its peripheral edge. As shown in Figure 1, the cylindrical portion 50c of the burner cap 50 is fitted into this burring hole portion 23. Since airtight sealing is required in this fitted portion to prevent the mixed gas from leaking downward, its vertical width La is preferably set to a relatively long dimension.

[0027] Figures 5 to 10 show the first to sixth steps, respectively, as an example of a method for manufacturing the upper mixing tube component MU described above. In this embodiment, these steps are executed sequentially. Here, The first and second steps correspond to specific examples of the "bulge formation step" as defined in this invention. The third step corresponds to specific examples of the "notched wall formation step" and the "step pressing step" as defined in the present invention. The fourth step corresponds to a specific example of the "step pressing process." Step 5 corresponds to a specific example of the "pre-drilling process". Step 6 corresponds to a specific example of the "burring hole formation step".

[0028] To manufacture the upper mixing tube component MU, the first step shown in Figure 5 is performed first. In this first step, a flat metal plate 3A is subjected to deep drawing to form an intermediate bulge 4A. This intermediate bulge 4A is the basis for the final finished bulge 4 (the final finished bulge 4 shown in Figures 1 to 3), and has a peripheral wall portion 40 and an upper wall portion 41 that rise upward from the plate-like region 3. However, this intermediate bulge 4A is lower in height and slightly larger in diameter than the final finished bulge 4. The final finished bulge 4 is taller than, for example, the bulge 2 of the lower mixing tube component ML (see Figure 1), and is difficult to form in a single deep drawing process. Taking this into consideration, the intermediate bulge 4A is formed first. The punch and die used in the first deep drawing process are the same as those used in general deep drawing processes, and their illustration and explanation are omitted. Furthermore, this first step may be repeated multiple times as a preliminary step before carrying out the second step, and each time it is repeated, the bulging portion 4A may be gradually changed to a shape and size suitable for carrying out the second step.

[0029] In the second step shown in Figure 6, the bulge 4A formed in the first step is further subjected to deep drawing to form a bulge 4'. This bulge 4' is taller than the bulge 4A, and an initial notched wall portion 45a is formed on the upper part of the peripheral wall portion 40. The initial notched wall portion 45a is the initial form portion (prototype portion) of the notched wall portion 45.

[0030] As shown in Figures 6(c) and 6(d), the punch 7 used for deep drawing in this second step has a notch 70 formed near the tip of its outer surface. This notch 70 is a part of the peripheral wall 40 of the bulge 4' that is intended to be avoided from actively pressing the part where the notched wall 45 is to be formed. The die 8 does not have a configuration in which a partial protrusion is provided in the area corresponding to the notch 70 of the punch 7, and has a configuration similar to that of a general deep drawing die (a cylindrical one). In the figure, reference numeral 79a indicates the workpiece holding member (reference numeral 79b in Figure 7(c) is the same). In a typical deep drawing process, a portion of the peripheral wall portion 40 of the bulge portion 4' is formed in the shape shown by the dashed line in Figure 6(d), for example. In contrast, according to the second step of this embodiment, the portion corresponding to the notch portion 70 is located inward from the shape shown by the dashed line, and the initial notched wall portion 45a is formed.

[0031] In the third step shown in Figure 7, the bulge 4' formed in the second step is further deep-drawn to form a bulge 4 with a final finish on the peripheral wall 40 and the notched wall 45. In addition, a stepped indentation 41b is formed on the upper wall 41 of the bulge 4, and a part 30' of the upward convex portion 30 is also formed on the plate-like region 3. The stepped indentation 41b is a portion that is convex on the lower side and concave on the upper side, located in the central region of the upper wall 41 of the bulge 4.

[0032] As shown in Figures 7(c) and 7(d), the punch 7A and die 8A used for deep drawing in this third step are equipped with a notch 70 and a protrusion 80. The notch 70 of the punch 7A is a part for actively pressing the area of ​​the peripheral wall 40 of the bulge 4 where the notched wall portion 45 is to be formed (the area where the initial notched wall portion 45a has already been formed). However, the notch 70 of the punch 7A can be the same shape and size as the notch 70 of the punch 7 shown in Figure 6, and in this embodiment, such a configuration is used. The protruding portion 80 of the die 8A is a part that protrudes so as to be able to sandwich a part of the peripheral wall portion 40 between itself and the notched portion 70 of the punch 7A. By using the deep drawing process described above with the punch 7A and die 8A, a notched wall portion 45 in the final finished state can be formed on the peripheral wall portion 40 of the bulging portion 4. Furthermore, the punch 7A and die 8A are also provided with a combination of a recess 78 and a convex portion 88 for forming the stepped pressing portion 41b, as well as a combination of a convex portion 77 and a recess 87 for forming a part 30' of the upward convex portion 30.

[0033] In the fourth step shown in Figure 8, the stepped indentation portion 41b and the upward convex portion 30 of the upper wall portion 41 of the bulging portion 4 are subjected to finishing processes to form them to the final target shape and size. As previously described, the stepped indentation portion 41b is located in the central region of the upper wall portion 41 of the bulging portion 4, and is convex on the lower side and concave on the upper side.

[0034] In the fifth step shown in Figure 9, a pilot hole 43a for the burring hole 43 is formed in the stepped pressing portion 41b. This pilot hole 43a has a smaller diameter than both the stepped pressing portion 41b and the burring hole 43. In this fifth step, a slit 49a is also formed to facilitate the formation of the notch 49.

[0035] In the sixth step shown in Figure 10, a burring hole 43, slightly larger in diameter than the pilot hole 43a, is formed in the stepped recess 41b of the upper wall portion 41 of the bulging portion 4. At this time, the remaining portion of the stepped recess 41b that was on the outer circumference of the pilot hole 43a is pressed downward to form a burring portion 44. In this sixth step, the area where the slit 49a of the upper wall portion 41 was formed is also processed to create a notch 49.

[0036] Through the series of processes described above, it is possible to properly manufacture the upper mixing tube component MU shown in Figures 2 and 3. According to the manufacturing process described above, it is possible to prevent the formation of a raised portion on the upper wall portion 41 of the bulging portion 4.

[0037] Figure 11 shows the proportion 1 of this embodiment. In this proportion 1, after forming the bulge 4, the upper part of the bulge 4 is pressed from the outside to form a notched wall portion 45e. With this method, a part of the notched wall portion 45e is raised by an appropriate dimension Lb on the upper wall portion 41 of the bulge 4, making it difficult to properly place the burner cap 50 on the upper wall portion 41. In contrast, this embodiment makes it possible to avoid such a risk.

[0038] Furthermore, according to this embodiment, in the third step shown in Figure 7, the notched portion 70 of the punch 7A and the protruding portion 80 of the die 8A are used to compress and form the notched wall portion 45, and this notched wall portion 45 is ultimately finished to the desired shape and size. However, in the preceding second step, when forming the initial notched wall portion 45a, the area to be formed of the notched wall portion 45 is not strongly compressed by both the punch 7 and the die 8. Therefore, it is possible to avoid generating excessive stress in the area to be formed of the notched wall portion 45.

[0039] Furthermore, as a method for forming the burring hole portion 43, a stepped indentation portion 41b is formed on the upper wall portion 41 of the bulging portion 4, and a part of this stepped indentation portion 41b is formed as the burring portion 44. This suppresses thinning of the burring portion 44 and makes it less likely for cracks to occur in the burring portion 44.

[0040] The present invention is not limited to the embodiments described above. The specific configuration of each step in the method for manufacturing the mixing tube component of a stove burner according to the present invention can be modified in various ways within the scope intended by the present invention.

[0041] In the above-described embodiment, a notched wall portion, which is notched in side view, was formed on the peripheral wall of the bulging portion through a total of two steps, the second and third steps. However, the present invention is not limited thereto. The notched wall portion may be formed in only one step, or through three or more steps. The specific shapes and sizes of each part of the mixing tube components to be manufactured, such as bulging sections and notched wall sections, are not limited. [Explanation of symbols]

[0042] B. Stove burner M mixing tube MU mixing tube component (upper mixing tube component) 3. Plate-like region 3A metal plate 4 Bulge 40 Peripheral wall section 41 Upper wall 41b Stepped Pressing Section 43 Burring hole 43a Pilot hole (for burring hole) 44 Burring section 45 Notch wall 45a Initial notch wall 7,7A Punch 70 Notch (of the punch) 8.8A die

Claims

1. A bulge formation step involves using a punch and die to deep draw a metal sheet as raw material, thereby forming a bulge having a cylindrical peripheral wall portion that rises upward from the plate-like region of the metal sheet and an upper wall portion connected to the upper part of this peripheral wall portion. A notched wall forming step, in which a part of the circumferential direction of the upper part of the peripheral wall is made into a notched wall portion in a side view, A method for manufacturing a mixing tube component of a stove burner, having the following characteristics: A method for manufacturing a mixing tube component of a stove burner, characterized in that, during the execution of the bulge formation step, the punch used is one having a notch formed therein corresponding to the notched wall portion, and the die used is one that is cylindrical and does not correspond to the notch of the punch.

2. A method for manufacturing a mixing tube component of a stove burner according to claim 1, The deep drawing process in the bulge formation step is performed multiple times, and each time it is performed, the size of the bulge is changed to approach the final target size. A method for manufacturing a mixing tube component of a stove burner, wherein, at least during the final deep drawing process, a punch having the notched portion formed therein is used as the punch.

3. A method for manufacturing a mixing tube component of a stove burner according to claim 1 or 2, A method for manufacturing a mixing tube component of a stove burner, wherein the notched wall forming step is performed after the bulging step, and the punch used is one in which the notch is formed, and the die used is one in which a projection corresponding to the notch of the punch is formed.

4. A method for manufacturing a mixing tube component of a stove burner according to claim 1, The process further includes a step of forming a burring hole in the upper wall, in which a burring hole is formed in the upper wall, in which a cylindrical burring portion that protrudes downward is located at the periphery, As a step performed before the burring hole formation step, A step-pressing step is performed to form a stepped portion that is convex on the lower side and concave on the upper side in the central region of the upper wall of the bulging portion, The process of drilling a pilot hole in the stepped portion, which is smaller in diameter than the stepped portion and the burring hole, Furthermore, it possesses A method for manufacturing a mixing tube component of a stove burner, wherein in the step of forming the burring hole, the burring hole is provided in the stepped pressing portion, and a part of the stepped pressing portion is formed as the burring portion.

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