JP2008119731A - Method of manufacturing center-bulged plate member with large thickness - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a method of manufacturing a center-bulged plate member with large thickness by which the target plate member can be manufactured without wasting material by employing a method of forming a base stock composed of a round bar into a special shape instead of a conventional method of obtaining a blank material by blanking a platy material with a press. <P>SOLUTION: The method of manufacturing the center-bulged plate member with large thickness includes: a first step in which the base stock obtained by cutting off the round bar is axially compressed with a die and both end parts of the resultant base stock are formed hemispherical and also the center part thereof is bulged to a large diameter, and a first semi-formed material is formed by connecting the interval between both hemispherically formed end parts and the bulged center part by means of an intermediate part having suitable shape; and a second step in which the above first semi-formed material is deformed into the platy shape between two pieces of the dies having two sandwiching and pressing surfaces parallel to each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an outer bulging plate member (hereinafter simply referred to as a bracket) having a large thickness, a small end, and a large central portion, such as an exhaust pipe bracket for coupling an engine and an exhaust pipe of a motorcycle. The present invention relates to a manufacturing method suitable for manufacturing the material by press working.

  The exhaust pipe bracket 10 is used to attach the exhaust pipe 50 to the engine 51 (see Patent Document 1). As shown in FIGS. 4 and 5, the exhaust pipe bracket 10 includes the exhaust pipe 50. Used for attachment to the engine 51, a relatively large exhaust pipe hole 10a for passing the exhaust pipe 50 through the center, and two relatively small attachment holes 10b for passing bolts 52 planted in the engine 51. 10b, so that the outer shape is the middle-bulged shape. Since a strong force for fixing the exhaust pipe 50 to the engine 51 acts on the bracket 10, the thickness of the bracket 10 is about 8 mm despite being a relatively small part of about 100 mm × 70 mm.

  As shown in FIG. 3A, the bracket 10 having such a shape is manufactured by using a strip-shaped steel plate 61 as a raw material and punching it with a press using a punch 62, that is, a blank material 63. . Next, as shown in FIG. 2 (2), the exhaust pipe hole 10a and the mounting hole 10b are perforated by drilling or pressing, and the edge of each hole is shown in FIG. 3 (3). Chamfer and finish.

  However, in the step of punching the blank material 63 from the steel plate 61, when the blank material 63 is punched from the steel plate 61 as a raw material, the remaining material 61a is greatly deformed, and the portion where the steel plate 61 is not deformed to continue the processing. If it is going to punch out from, the steel plate 61 must be sent large, and therefore the portion to be discarded becomes large. Therefore, not only was the material yield wasted and resources were wasted, but also the product price was adversely affected.

  As a measure to improve this, it was conceived that multiple members of the same shape formed using a thin plate material could be overlapped and welded to make them thicker, but the number of forming increases as well as the welding process. However, the manufacturing cost increased.

Further, in the conventional manufacturing method, since the blank material is perforated and chamfered, the material of the hole portion and the chamfered portion is discarded as scrap material, which further increases the waste of material. .
JP 2001-280127 A

  It is intended to obtain a new manufacturing method in place of the conventional method of punching a plate-shaped material by a press and obtaining a blank material. In order to obtain a plate-shaped member without using a plate material as a material, it is conceivable to crush a round bar with a press machine, but even if it is simply crushed, only a single material can be obtained. Therefore, it is required to obtain a crushing method that minimizes processing after processing or material waste.

  In the present invention, a material obtained by cutting a round bar is clamped between two molds that move forward and backward facing each other, compressed in the axial direction to form both ends into a substantially hemispherical shape, and the central portion is substantially A first step of forming a first semi-finished product having a spherical shape and connecting the both end portions and the central portion with an appropriately shaped intermediate portion, and two pressing surfaces parallel to each other. And a second step of deforming by pinching between two molds having a main feature.

  According to the present invention, a round bar is used as a raw material, and a blank material is made by enlarging a necessary portion of a relatively small material. Therefore, a conventional manufacturing method for making a blank material by deleting unnecessary portions from a large material. Compared with this, the yield of the material is good and the resource can be saved.

  Hereinafter, the manufacturing method according to the present invention will be described with reference to the illustrated embodiments. In FIG. 1 and FIG. 2, reference numeral 10 denotes a thick middle expansion plate member, specifically, an exhaust pipe mounting bracket. The bracket 10 is obtained by cutting a material 11, that is, a steel round bar into predetermined dimensions. The outer diameter of the material 11 is selected to be thicker than the thin shaft portion 12d of the first semi-finished product 12 described later and thinner than the central portion 12b. Further, the length of the material 11 is set to be shorter than that of the first semi-finished product 12.

  FIG. 1 (2) shows the appearance of the first semi-finished product 12 made in the first step. As shown in FIG. 2 (2), the first semi-finished product 12 clamps the material 11 in the axial direction by a first mold 31 composed of two mold members 31a and 31b which are opposed to each other. Made. In addition, the 1st process here means the whole operation process until the 1st semi-finished product is made, and is different from each operation | work (every 1 type).

  The mold members 31a and 31b have symmetrical mold surfaces, and squeeze the material 11 in the axial direction while narrowing the vicinity of the end to a small diameter. That is, the end portion of the material 11 is squeezed by the mold members 31a and 31b, moved in the direction opposite to the traveling direction, and pushed into the escape portion 32a while being hemispherically swelled. 12a and the small-diameter thin shaft portion 12d are simultaneously molded.

  At that time, as both mold members 31a and 31b advance, most of the material is pushed in the traveling direction and flows toward the center in the axial direction. Therefore, the center of the raw material 11 is pushed by the material flowing in from both sides and swells in a spherical shape in the circumferential direction, and an elongated spherical central portion 12b whose center swells outward is formed. Reference numerals 12c and 12c denote substantially conical intermediate portions connecting the narrow shaft portion 12d and the enormous central portion 12b, and will be described later by appropriately selecting the angles of the intermediate portions 12c and 12c. It is possible to arbitrarily adjust the line connecting the both end portions 12a, 12a and the enormous central portion 12b to be convex outward from the tangent or convex inward.

  FIG. 1 (3) shows the appearance of the second semi-finished product 15 made in the second step. FIG. 2 (3) shows the second semi-finished product 15 sandwiched between an upper die 35a and a lower die 35b forming a second die 35 used in the second step. In the second step, the first semi-finished product 12 is crushed flat by the second mold 35. At this time, the hemispherical ends 12a, 12a are formed into spherical portions of the mounting holes 10b, 10b. The enormous central portion 12b becomes a portion of the exhaust pipe hole 10a.

  And since the said intermediate part 12c and the thin shaft part 12d become flat, expanding outward, it changes to the part which connects both the end parts 12a and 12a and the enormous center part 12b. In order to reduce the weight of the bracket 10, this shape is set so as to be slightly recessed from the tangent line connecting the both end portions 12a, 12a and the enormous central portion 12b.

  The upper mold 35a and the lower mold 35b that sandwich the second semi-finished product 15 are provided with projections 35c and 35c at positions corresponding to the exhaust pipe hole 10a and the mounting hole 10b, respectively. Pilot holes 15a and 15b for the perforating process are formed. Further, a relief space 35d is formed on the side in the advancing direction so that the flow of the material is not hindered when the second semi-finished product 15 is sandwiched from above and below between the molds 35a and 35b. The surplus extruded from the space bulges into the arc. Therefore, when the excessively expanded portion is removed in the step of trimming the outer shell in the subsequent third step, the edge portion is left without being removed and left as the chamfered portion 15c on the outer surface. In FIG. 2 (3), a two-dot chain line 15e indicates a position to be removed in the process of trimming the outer shell.

  As is apparent from the cross-sectional view shown in the lower side of FIG. 2 (3), the shapes of both the lower holes 15a and 15a are larger than the product dimensions indicated by the two-dot chain line 15f in the figure, and the bottom. Is a dish-shaped portion smaller than the product size, and is formed from both sides at the same position. That is, when the exhaust pipe hole 10a and the mounting hole 10b having a predetermined diameter are drilled in the subsequent third step, the entrance portion of the dish-shaped slope is left as the chamfered portion 15d around the hole.

  1 (4) and 2 (4) show the final molded product after the third step. In the third step, processing such as drilling and trimming (including thin shaving, so-called shaving) is added to the lower holes 15a, 15a provided in the second semi-finished product 15 made in the previous step and the outer shell. Finish to the specified dimensions. Therefore, if this molded final product is subjected to plating or other heat-resistant surface treatment, it becomes a bracket 10 as a product.

  64 is waste material removed from the portions of the lower holes 15a and 15a in the third step, and 65 is waste material removed from the contour portion. Since the outer shape of the outer shell at the end of the second step is excellent in a loose arc shape with the outer edge bulging outward and the appearance, the step of trimming the outer shell portion is essential in the third step. By removing this process instead of the process, there is an advantage that the appearance is improved and the problem that the hand is cut is eliminated.

  As described above, according to this embodiment, as compared with the conventional manufacturing method using a blank material punched out from a strip-shaped material larger than a bracket as a product as a material, the small material that is cut out from a rod-shaped steel material is not much different from the bracket. In addition to avoiding large material loss due to the use of rods, it is also possible to obtain products by removing holes and chamfers for bolts and exhaust pipes from flat plate blanks during molding. In contrast, a plate-shaped pilot hole is made in the process of crushing a round bar into a flat plate shape, so chamfering is unnecessary and only the bottom of the pilot hole needs to be drilled. There is no.

It is an external view which shows the deformation | transformation process of the raw material by the manufacturing method which concerns on this invention. It is process drawing which shows the shape of the product by the manufacturing method shown in FIG. It is an external view equivalent to FIG. 1 which shows the conventional manufacturing method. It is an external view which shows the combined state of an engine and an exhaust pipe. FIG. 5 is a cross-sectional view showing a main part of FIG.

Explanation of symbols

10 Bracket 10a Exhaust pipe hole 10b Mounting hole 11 Material 12 First semi-finished product 12a Both ends 12b Central portion 12c Intermediate portion 12d Fine shaft portion 15 Second semi-finished product 15a, 15b Lower hole 15c Chamfered portion 15d Chamfered portion around hole 31st 1 mold 31a, 31b mold member 35 second mold 35a upper mold 35b lower mold 35c protrusion 35d relief space 50 exhaust pipe 51 engine 52 bolt 61 strip-shaped steel plate 61a remaining material 62 punch 63 part to be a bracket (blank material) )
64, 65 Waste material 15e, 15f Two-dot chain line

Claims (3)

  The material obtained by cutting the round bar is clamped between two molds that move forward and backward facing each other, compressed in the axial direction to form both ends into a substantially hemispherical shape, and the center part is enlarged into a substantially spherical shape. , A first step of forming a first semi-finished product having a shape in which the both end portions and the central portion are appropriately connected by an intermediate portion, and two pieces having two clamping surfaces parallel to each other. A method for manufacturing a thick-walled medium-bulged plate member, including a second step of deforming by clamping between the molds.   2. The manufacture of a thick-walled medium-expansion plate member according to claim 1, wherein a protrusion having an appropriate shape is provided on at least one surface of the two clamping surfaces used in the second step, and a prepared hole is formed in a subsequent drilling step. Method.   2. The production of a thick-walled medium-expansion plate member according to claim 1, wherein at least one of the semi-finished pilot hole or outer shell formed in the second step includes a third step of trimming leaving the lower hole or outer edge. Method.

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