WO1999047289A1 - Method of manufacturing sheet metal product having cylindrical portion at inner circumferential side thereof - Google Patents

Abstract

A method of manufacturing a sheet metal product having a cylindrical portion at the inner circumferential side thereof, capable of forming a cylindrical portion (84) at the inner circumferential side of a sheet metal work (W) without using welding and burring processes, making unnecessary a welding operation which is troublesome, and which deteriorates the working environment, and reducing the restrictions on the increasing of the axial length of the cylindrical portion (84). The gist of the method resides in that a process for rolling a cylindrical portion (84) on an opened edge section (82) of a sheet metal work (W), which has an opening (81), by pressing a surface (26) of an inner mold (25) provided in the opening (81) against the opened edge section (82) with the inner mold (25) moved in the diametrically outward direction of the work (W) as the sheet metal work (W) is turned around the axis of the opening (81) with the work (W) set in a predetermined position is carried out. According to this method, a cylindrical portion (84 ) can be formed at theinner circumferential side of the sheet metal work (W) without using welding and burring processes.

Description

 Description Manufacturing method of sheet metal products having a cylindrical part on the inner circumference

 The present invention relates to a method for manufacturing a sheet metal product having a cylindrical portion on an inner periphery. Specific examples of the sheet metal product manufactured according to the present invention include Puri. Further, the tubular portion of the sheet metal product manufactured according to the present invention serves, for example, as a boss portion for attaching the sheet metal product to a shaft. Background art

When a tube is provided on the inner periphery of a sheet metal work having an opening, conventionally, a separately manufactured tube is welded to the inner periphery of the work, or the work is subjected to pearling. The start of the tube was being performed. However, there was a problem that the welding operation was troublesome and the working environment was deteriorated. On the other hand, the cylindrical part formed by the cooling process has many restrictions on increasing the axial length, and both the one side and the other side of the work SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a problem that a cylindrical portion cannot be set up in a conventional manner. Tube section on inner circumference of sheet metal work In order to be able to form a work, it is troublesome to perform welding that deteriorates the working environment and to increase the shaft length. An object of the present invention is to provide a method for forming a tubular portion having no connection portion on the inner periphery of a sheet metal work, in other words, a method for manufacturing a sheet metal product having a tubular portion on the inner periphery. ing. Disclosure of the invention

 In order to achieve the above object, a method for manufacturing a sheet metal product having a cylindrical portion on the inner periphery according to the present invention is a method for manufacturing a sheet metal product having an opening, and having an inward bifurcated annular protrusion at an opening edge thereof. While rotating the work in a fixed position around the axis of the opening, the inner die provided in the opening is moved outward in the radial direction of the work to move the inner die. The step of pressing the mold surface against the annular protruding piece and extending the annular protruding piece in a direction along the axis of the opening to form a cylindrical portion is performed.

 According to this method, the tubular portion can be formed on the inner periphery of the sheet metal product without using welding or burring.

 At this time, while rotating the circular sheet metal work, press the outer mold that has been moved inward in the radial direction of the work to form a groove on the outer periphery of the work. A method of performing the processing is disclosed, for example, in Japanese Patent Publication No. 5-81339.

However, a tube is provided on the inner periphery of the sheet metal work. Conventionally, the above-mentioned welding and burring processes have been performed, and as in the present invention, a sheet metal work is rotated and arranged in an opening of the work while rotating the work. By moving the mold outward in the radial direction, the mold surface of the inner mold is pressed against the inward bifurcated annular protruding piece, and the annular protruding piece is stretched. The method of forming a part has been proposed according to the present invention. In addition, when some processing is performed on a sheet metal work using a mold, at present, a method of moving an outer mold disposed outside the work with respect to the work is a usual means. Therefore, by adopting the means of moving the inner die radially outward within the opening of the rotating sheet metal work as in the present invention, the inner peripheral portion has a cylindrical portion. The method of manufacturing a sheet metal product is not in line with the technology disclosed in the above-mentioned Japanese Patent Publication No. 5-81339.

In the present invention, the inward bifurcated annular protruding piece can be formed by rubbing an opening edge of an opening provided in a plate portion of a sheet metal work at a middle portion in a thickness direction thereof. It is. In this case, while rotating the work made of sheet metal at a fixed position around the axis of the opening, the inner mold for scraping provided in the opening is moved outward in the radial direction of the work. Further, for the rubbing, a V-shaped rubbing surface provided in the inner mold is pressed against the middle in the thickness direction of the opening edge of the opening, and the opening edge is cracked. By performing the steps described above, it is possible to adopt a method of forming the annular protruding piece having an inward bifurcated shape. The process of pressing the inner mold for rubbing against the edge of the opening of the work and rubbing it is the same as described above for the same reason as described above. It is not intended to be in line with the technology disclosed in the above publication.

 In order to achieve the above object, another method of manufacturing a sheet metal product having a tubular portion on the inner periphery according to the present invention is to rotate a sheet metal work having an opening at a fixed position around the axis of the opening. Then, by moving the inner mold provided in the opening to the outside in the radial direction of the work, the mold surface of the inner mold is pressed against the opening edge of the work to open the work. O Rolling the cylindrical part to the edge.

 According to this method as well, it becomes possible to form a tubular portion on the inner periphery of a sheet metal product without using welding or burring.

 The process of pressing the mold surface of the inner mold placed in the opening of the work against the edge of the opening of the work and rolling the cylindrical portion on the opening edge is performed for the same reason as described above. Therefore, it is not something that is in line with the technology disclosed in the above-mentioned Japanese Patent Publication No. 5-813339.

The step of rolling the opening edge of the work into a cylindrical shape can be performed irrespective of the thickness of the sheet metal work. In other words, when the work is thick enough to roll the cylinder, the opening edge It is possible to form the cylindrical part by pressing the inner mold surface directly on the part. On the other hand, if the work is too thin to roll the cylinder before, the process of thickening the opening edge of the work is performed. After that, the above rolling may be performed.

 The step of thickening the edge of the opening of the work includes rotating the work having the opening at a fixed position around the axis of the opening while increasing the thickness of the work provided in the opening. The inner mold is moved radially outward of the work so that the molding surface for thickening the inner mold is pressed against the opening edge of the work. It is possible. The process of increasing the thickness of the opening edge in this manner is disclosed in the above-mentioned Japanese Patent Publication No. 5-8133 9 for the same reason as described above. It's not about keeping pace with technology.

 The sheet metal product manufactured by the present invention has a cylindrical portion protruding on both one side and the other side, but has a cylindrical portion protruding only on one side. It may be.

In the case of manufacturing a sheet metal product having a cylindrical portion protruding from both the one surface side and the other surface side, the step of rolling the cylindrical portion includes removing the meat of the opening edge of the work from the work. It is desirable that this is a process of forming a cylindrical shape on one side and the other side. According to this method, it is possible to perform the cylindrical portion protruding on one side and the other side in one process. In the case of manufacturing a sheet metal product in which the cylindrical portion protrudes on both the one surface side and the other surface side, when performing the above-described thickening step, the thickening step is performed as described above. It is desirable that the process be a process in which the meat at the edge of the opening of the work is bulged in one side and the other side of the work. In addition, it is desirable that the step of rolling the cylindrical portion is a step of forming the meat at the opening edge of the work into a cylindrical shape on one side and the other side of the work. . According to these methods, it is possible to easily increase the protruding length from one side of the cylindrical portion and the protruding length from the other side.

On the other hand, in the case of manufacturing a sheet metal product having a cylindrical portion protruding only on one surface side, the step of rolling the cylindrical portion involves removing the meat at the opening edge of the work on one surface of the work. It is desirable that this is a process in which only the side is raised in a cylindrical shape. Also, in the case of manufacturing a sheet metal product having a cylindrical portion protruding only on one side, when performing the above-described thickening step, the thickening step is performed by opening the work. Desirably, the process is to bulge the edge meat only on one side of the work. Further, it is preferable that the step of rolling the cylindrical portion is a step of forming the meat at the opening edge of the work into a cylindrical shape only on one surface side of the work. According to these methods, it is possible to easily increase the protruding length of the cylindrical portion from one surface side. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a partially cutaway front view showing a preparation stage for a first embodiment of the manufacturing method according to the present invention.

 FIG. 2 (a) is a partially broken front view in which the main part of FIG. 1 is enlarged, and FIG. 2 (b) is a partially broken front view for explaining the scraping process. FIG. 7 is a partially broken front view showing another preparation stage.

 FIG. 4 (a) is a partially broken front view in which the main part of FIG. 3 is enlarged, and FIG. 4 (b) is a partially broken front view for explaining a tubular portion forming step.

 FIG. 5 is a partially broken front view showing a preparation stage for a second embodiment of the manufacturing method according to the present invention.

 Fig. 6 (a) is a partially cutaway front view in which the main part of Fig. 5 is enlarged, and Fig. 6 (b) is a partially cutaway front view for explaining the preceding thickening step.

 FIG. 7 is a partially broken front view showing another preparation stage for the second embodiment.

 FIG. 8 (a) is a partially broken front view in which the main part of FIG. 7 is enlarged, and FIG. 8 (b) is a partially broken front view for explaining the subsequent thickening step.

 FIG. 9 is a partially cutaway front view showing still another preparation stage for the second embodiment.

Fig. 10 (a) is a partially cutaway front view in which the main parts of Fig. 9 are enlarged. Figure (b) is a partially cutaway front view for explaining the cylindrical part rolling process.

 FIG. 11 is a partially broken front view showing a preparation stage for a third embodiment of the manufacturing method according to the present invention.

 Fig. 12 (a) is a partially broken front view in which the main parts of Fig. 11 are enlarged, and Fig. 12 (b) is a partially broken front view for explaining the thickening process.

 FIG. 13 is a partially cutaway front view showing still another preparation stage for the first embodiment.

FIG. 14 (a) is a partially cutaway front view in which the main part of FIG. 13 is enlarged, and FIG. 14 (b) is a partially cutaway front view for explaining the cylindrical portion rolling process. BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to FIGS. In the embodiment shown here, the step of forming an inward bifurcated annular projecting piece 8 3 at the opening edge 8 2 of a flat circular sheet-metal work W having an opening 81 (an annular projecting piece forming step) Step) and a step of forming the inward bifurcated annular protruding piece 83 of the sheet metal work W having undergone this annular protruding piece forming step into a cylindrical shape (cylindrical portion forming step). The work W made of sheet metal prepared in the annular projecting piece forming step may be formed as a flat plate portion W1 around the opening 81, and the overall shape of the work W is as shown in the figure. Even a flat thing, Alternatively, it may be in the form of a force.

As shown in Fig. 1 and Fig. 3, working equipment with the same structure is used in the above two processes. This working device includes a work holding member 1 and a slide mechanism 3. The work clamping member 1 has a rotary mounting table 12 around which the drive belt 11 is wound and a presser table 13 arranged opposite to the rotary mounting table 12. The work W is held between the rotary mounting table 12 and the presser table 13 and held at a fixed position. The arrow a indicates the pressing direction of the holding table 13. In the above two processes, two types of inner dies 21 and 25 are used separately. The slide mechanism 3 includes a cam plate 31 and a movable base 32 that is horizontally slid by rotation of the cam plate 31, and is mounted on the movable base 32. The inner mold 21 or the inner mold 25 is connected to the rotary drive shaft 33. The rotational drive shaft 33 has a fixed position with respect to the movable base 32, and its rotation axis coincides with the axis of the inner die 21 or the inner die 25 mounted on the movable base 32. Therefore, when the rotational force is transmitted to the rotary drive shaft 33, the inner die 21 or the inner die 25 mounted on the movable base 32 together with the rotary drive shaft 33 rotates as indicated by the arrow R1. When the cam plate 31 is rotated, the inner die 21 or the inner die 25 mounted on the movable base 32 together with the movable base 32 slides and moves in the horizontal direction (arrow S). In addition, rotating the inner die 21 or the inner die 25 mounted on the movable base 32 and moving the inner die 25 in the horizontal direction are performed simultaneously. Has become possible.

 The mark W used in the annular projecting piece forming process shown in FIGS. 1 and 2 is circular, and has a circular opening 81 in a plate portion W1 at the center thereof. 2 is the target part. Then, when the rotary mounting table 12 of the work holding member 1 is driven to rotate, the work W is pressed against the rotary mounting table 12 by the presser table 13 and the opening 8 1 Rotate as shown by the arrow R 2 at a fixed position around the axis of.

 The work W used in the tubular portion forming step shown in FIGS. 3 and 4 is a work that has undergone an annular projecting piece forming step, and has an opening edge 8 2 at its opening edge 8 2. 3 and its annular projection 83 is the target portion. Then, when the rotary mounting table 1 2 of the work holding member 1 is driven to rotate, the work W is pressed against the rotary mounting table 12 by the presser table 13, and the opening 8 1 of the opening 8 1 is closed. Rotate in a fixed position around the axis as indicated by arrow R2.

 Next, the annular projecting piece forming step and the tubular part forming step will be described.

Glue ring piece forming process>

As shown in FIGS. 1 and 2, the inner die 21 used in the annular projecting piece forming step is a split inner die having a split surface 22 having a V-shaped cross section. In the preparation stage of this process, as shown in Fig. 1, the work W is clamped by the work clamping member 1 and held in a fixed position, and the inner mold for friction 21 is mounted on the movable base 32. Opening of Work W 8 Deployed within 1. Figure 2 (a) shows the positional relationship between the work W and the inner mold 21 for scraping in this preparation stage.

 As shown in Fig. 2 (a), the work W is rotated at a fixed position around the axis of the opening 81 as indicated by an arrow R2, and at the same time, the inner mold 21 for scraping is rotated by an arrow R1. While rotating as shown in Fig. 2 (b), slide laterally as indicated by the arrow S in Fig. 2 (b) to move the workpiece W radially outward. By doing so, the rubbing surface 2 2 of the inner mold for rubbing 2 presses the opening edge 8 2 of the work W shown in FIG. As shown in FIG. 2 (b), the rubbing surface 22 rubs the opening edge 81 at the middle portion in the thickness direction as shown in FIG. O

Tube forming process>

 As shown in FIGS. 3 and 4, the inner mold 25 used in the tubular portion forming step has a concavely shaped mold surface 26 formed by a cylindrical surface. In the preparation stage of this process, as shown in FIG. 3, the work W having undergone the above-described annular projection forming process is held by the work holding member 1 to be held at a fixed position, and the inner die 25 is movable. It is mounted on the platform 32 and placed in the opening 81 of the work W. Figure 4 (a) shows the positional relationship between the work W and the inner mold 25 at this preparation stage.

As shown in Fig. 4 (a), the stroke W is rotated at a fixed position around the axis of the opening 81 as indicated by the arrow R2, and at the same time, the inner mold 25 is rotated by the arrow R1. Rotate as shown by arrow S in Fig. 4 (b). And move it outward in the radial direction of the work W. In this case, the mold surface 26 of the inner mold 25 presses the inward bifurcated annular projection 83 of the work W shown in FIG. 4A, and the annular projection 83 is formed. It is extended in a direction along the axis of the opening 81 to form a cylindrical portion 84. This produces the sheet metal product M ο

 The sheet metal product M manufactured in this manner has a cylindrical portion 84 standing up on both one side and the other side. In such a sheet metal product M, the cylindrical portion 84 can be used, for example, as a boss portion through which a shaft passes.

 When performing the above-described annular projecting piece forming step or tubular section forming step, when the inner dies 21 and 25 are pressed against the opening edge portion 82 of the work W or the annular projecting piece 83, they do not slip. It is desirable that it rotates in a state. For this purpose, the inner dies 21 and 25 should be rotated in synchronization with the work W. In this manner, the smoothness of the inner surface (surface) of the annular projection 83 and the cylindrical portion 84 is improved, and the inner surface of the cylindrical portion 84 is also used as a contact surface with the seal ring. become able to.

A second embodiment of the present invention will be described with reference to FIG. 5 to FIG. The embodiment shown here is a two-step process (a thickening process in the first stage and a thickening process in the second stage) of thickening the opening edge 8 2 of the circular sheet metal work W having the opening 81. The process of forming a cylindrical part on the inner periphery of the sheet metal work W that has undergone those thickening steps (the cylindrical part rolling) Manufacturing process). The sheet metal workpiece W prepared in the thickening process only needs to be formed as a flat plate portion W1 around the opening 81, and the overall shape of the work W is as shown in the figure. It may be flat or cup-shaped.

 As shown in Fig. 5, Fig. 7 and Fig. 9, in the thickening process and the cylindrical part rolling process, the same working equipment as that described in Fig. 1 and Fig. 3 is used. The code is attached.

 The work W used in the pre-thickening process shown in FIGS. 5 and 6 has a circular shape, and has a circular opening 81 in a plate portion W1 at the center thereof, and has an opening edge. 8 2 is the part to be machined. Then, when the rotary mounting table 12 of the work holding member 1 is driven to rotate, the work W is pressed against the rotary mounting table 12 by the presser table 13 and the opening 8 1 of the opening 8 1 is closed. Rotate in a fixed position around the axis as indicated by arrow R2.

 The work W used in the subsequent thickening step shown in FIGS. 7 and 8 is a work that has undergone the preceding thickening step, and its opening edge 82 is slightly thickened. The opening edge portion 82 with a slightly enlarged thickness and a glans-shaped cross section is the portion to be machined. Then, when the rotary mounting table 1 2 of the peak holding member 1 is driven to rotate, the park W is pressed against the rotary mounting table 1 2 by the presser table 13, and the opening 8 is formed. Rotate in a fixed position around the axis 1 as indicated by arrow R2.

Work used in the cylindrical part rolling process shown in Fig. 9 and Fig. 10 W is a work that has gone through each of the thickening processes of the former stage and the latter stage. The opening edge portion 82 is sufficiently thickened, and the cross-sectional outline of such a sufficiently thickened portion is shown. The circular opening edge 82 is the processing target portion. Then, when the rotary mounting table 12 of the work holding member 1 is driven to rotate, the work W is pressed against the rotary mounting table 12 by the presser table 13 and the opening 8 1 Rotate as shown by the arrow R 2 at a fixed position around the axis of.

 Next, the above-described first-stage thickening structure, second-stage thickening step, and cylindrical portion rolling step will be described.

<First-stage thickening process>

 As shown in Fig. 5 and Fig. 6, the inner die used in the former thickening process

Reference numeral 27a denotes a pre-thickening 內 type having a pre-thickening molding surface 28a recessed into a ship bottom shape. In the preparation stage of this process, as shown in Fig. 5, the work W is sandwiched by the work clamping member 1 and held in a fixed position, and the inner mold 27a for thickening the former stage is moved to the movable platform.

It is mounted on 32 and deployed in the opening 81 of Work W. Fig. 6 (a) shows the positional relationship between the work W and the inner mold 27a for thickening in the pre-stage at this preparation stage.

As shown in Fig. 6 (a), the work W is rotated in a fixed position around the axis of the opening 81 as shown by the arrow R2, and at the same time, the inner mold 27a for thickening the former stage is rotated by the arrow. While rotating as indicated by the symbol R 1, it is slid laterally as indicated by the arrow S in FIG. 6 (b) and moved outward in the radial direction of the work W. In this way, the inner mold for thickening the former stage 2 7a 6a presses the opening edge 82 of the work W shown in Fig. 6 (a), so that the opening edge 82 has the thickness corresponding to the pressing force at that time. The ridge W bulges on one side and the other side in a bulging shape, and the opening edge portion 82 of the ridge W becomes thicker, forming a glans cross section.

Thickening process at the later stage>

 As shown in Figs. 7 and 8, the inner die used in the subsequent thickening process

Reference numeral 27b denotes a rear thickening inner mold having a rear thickening molding surface 28b recessed into an arc-shaped cross section. In the preparation stage of this process, as shown in Fig. 7, the work W is held between the work holding members 1 and held at a fixed position, and the inner mold 27b for thickening the rear stage is moved to the movable platform.

It is mounted on 32 and deployed in the opening 81 of Work W. Fig. 8 (a) shows the positional relationship between the work W and the inner mold 27b for thickening the latter stage in this preparatory stage.

As shown in Fig. 8 (a), the work W is rotated at a fixed position around the axis of the opening 81 as shown by the arrow R2, and at the same time, the inner mold 27b for the rear-stage thickening is moved by the arrow. While rotating as indicated by the symbol R 1, it is slid laterally as indicated by the arrow S in FIG. 8 (b) and moved outward in the radial direction of the work W. In this way, the rear thickening molding surface 28 b of the rear thickening inner die 27 b presses the opening edge 82 of the work W shown in FIG. 8 (a). According to the pressing force at that time, the flesh of the opening edge portion 82 bulges in a bulging shape on one side and the other side of the work W, and the opening edge portion 82 is thickened, and a substantially circular cross section is formed. It takes shape.

Glue Rolling Process>

 As shown in FIG. 9 and FIG. 10, the inner die 41 used in the cylindrical part rolling step has a concave die surface 42 formed by a cylindrical surface. In the preparatory stage of this process, as shown in FIG. 9, the work W having undergone the above-described thickening process of the first and second stages is sandwiched by the workpiece clamping member 1 and held in a fixed position. The inner die 41 is mounted on the movable base 32 and disposed in the opening 81 of the work W. Figure 10 (a) shows the positional relationship between the work W and the inner mold 41 in this preparation stage.

 As shown in Fig. 10 (a), the work W is rotated in a fixed position around the axis of the opening 81 as shown by the arrow R2, and at the same time, the inner die 41 is moved by the arrow R1. With the force not rotated in this manner, the workpiece is slid in the horizontal direction as indicated by the arrow S in FIG. 10 (b) and moved outward in the radial direction of the work W. In this case, the mold surface 42 of the inner mold 41 presses the sufficiently thick opening edge 82 of the work W shown in FIG. The meat of the opening edge portion 82 rises in a cylindrical shape on one surface side and the other surface side of the work W, and the cylindrical portion 84 is formed by rolling. As a result, a sheet metal product M is manufactured.

As for the sheet metal product M thus manufactured, similarly to the one shown in FIG. 4 (a), the cylindrical portion 84 stands on both one side and the other side. Therefore, in such a sheet metal product M, the cylindrical portion 84 is, for example, a boss portion through which a shaft passes. Available.

 When performing the above-described cylindrical part rolling process, it is desirable that the inner die 41 and the opening edge part 82 of the work W rotate without slipping. For this purpose, the inner die 41 may be rotated in synchronization with the work W. By doing so, the smoothness of the inner surface (surface) of the cylindrical portion 84 is improved, and the inner surface of the cylindrical portion 84 can be used as a contact surface with the seal ring. Become.

 In the second embodiment described with reference to FIGS. 5 to 10, the thickening step is divided into a first thickening step and a second thickening step, so that the work W is seated at the time of thickening. It is hard to buckle. Of course, if there is no fear of buckling, the thickening step may be performed in a single step.

 A third embodiment of the present invention will be described with reference to FIG. 11 to FIG. In the embodiment shown here, the step of thickening the opening edge portion 82 of the circular sheet metal work W having the opening 81 (thickening step), and the sheet metal working through the thickening step are described. Forming a cylindrical portion on the inner periphery of the work W (a cylindrical portion rolling process).

 As shown in Figs. 11 and 13, in the thickening process and the cylindrical part rolling process, the same working equipment as that described in Figs. 1 and 3 is used, so the same parts are used. The code is attached.

The work W used in the thickening process shown in FIGS. 11 and 12 has a circular shape, and has an opening 81 in a plate portion W1 at a central portion thereof. 2 is the target part. So Then, when the rotary mounting table 1 2 of the work holding member 1 is driven to rotate, the opening 8 1 is maintained while the work W is pressed against the rotary mounting table 12 by the presser table 13. Rotate as shown by the arrow R 2 in a fixed position around the axis of the. The work W made of sheet metal prepared in the thickening process only needs to be formed as a flat plate portion W1 around the opening 81, and the entire shape of the work W is as shown in the figure. It may be flat or cup-shaped.

 The work W used in the cylinder rolling process shown in FIGS. 13 and 14 is a work that has undergone a thickening process, and its opening edge portion 82 is sufficiently thickened. Thus, the opening edge portion 82 having a substantially circular cross-section and having a sufficiently large thickness is a portion to be processed. Then, when the rotary mounting table 1 2 of the work holding member 1 is driven to rotate, the mark W is pressed against the rotary mounting table 12 by the presser table 13, and the circumference of the axis of the opening 8 1 is maintained. Then rotate in the fixed position as indicated by arrow R2.

 Next, the above-described thickening step and cylindrical section rolling step will be described. Thickening process>

As shown in FIGS. 11 and 12, the inner mold 43 used in the thickening step is an inner mold having a concave-shaped thickened molding surface 44. In the preparation stage of this process, as shown in FIG. 11, the work W is clamped by the work clamping member 1 and held in a fixed position, and the thickening inner mold 4 4 is moved by the movable base 3 2. Work W Deployed in mouth 81. Figure 12 (a) shows the positional relationship between the work W and the inner mold 43 for thickening in this preparation stage.

 As shown in Fig. 12 (a), the work W is rotated in a fixed position around the axis of the opening 81 as indicated by an arrow R2, and at the same time, the inner mold 43 for thickening is indicated by an arrow. While rotating as R 1, slide in the horizontal direction as indicated by the arrow S in Fig. 12 (b) and move it outward in the radial direction of the work W. In this way, the thickened molding surface 44 of the thickening inner mold 43 presses the opening edge 82 of the work W shown in Fig. 12 (a). According to the pressing force, the meat of the opening edge portion 82 rises in a bulging shape on one surface side of the work W, and the opening edge portion 82 becomes thick.

Kubushi Roll Forming Process>

As shown in FIGS. 13 and 14, the inner die 45 used in the cylindrical part rolling step has a concave die surface 46 formed by a cylindrical surface. In the preparation stage of this process, as shown in FIG. 13, the work W that has undergone the above-described thickening process is held in place by being held by the work holding member 1 and the inner mold 45 is formed. Is mounted on the movable base 32 and is arranged in the opening 81 of the work W. The positional relationship between the work W and the inner mold 41 in this preparation stage is shown in Fig. 14 (a), as shown in Fig. 14 (a). At the same time, the inner die 45 is rotated at a fixed position around the axis of the opening 81, and at the same time, the inner die 45 is rotated as shown by the arrow R1 while the inner die 45 is rotated as shown by the arrow S in FIG. 14 (b). And slide it to the outside in the radial direction of the work W. In this case, the mold surface 46 of the inner mold 45 presses the sufficiently thick opening edge 82 of the work W shown in FIG. The meat of the opening edge portion 82 rises in a cylindrical shape on one surface side of the work W, and the cylindrical portion 84 is formed by rolling. As a result, a sheet metal product M is manufactured.

 As for the sheet metal product M thus manufactured, the cylindrical portion 84 stands up only on one side thereof. In such a sheet metal product M, the cylindrical portion 84 can be used, for example, as a boss portion through which a shaft passes.

 It is desirable that the inner die 45 and the opening edge portion 82 of the work W rotate in a non-slip state when performing the above-described cylindrical portion rolling process. For this purpose, the inner mold 45 may be driven to rotate in synchronization with the peak power W. By doing so, the smoothness of the inner surface (surface) of the cylindrical portion 84 is improved, and the inner surface of the cylindrical portion 84 can be used as a contact surface with the seal ring. become.

In the third embodiment, the step of increasing the thickness of the opening edge 82 of the work W is performed by expanding the thickness of the opening edge 82 of the work W to only one side of the work W. Since it is a process of building up in a protruding state, it is possible to easily obtain a sheet metal product M in which the cylindrical portion 84 is raised only on one surface side by performing the cylindrical portion rolling process. . Industrial applicability As described above, according to the method for manufacturing a sheet metal product having a tubular portion on the inner periphery according to the present invention, a sheet metal product having a tubular portion on the inner periphery can be obtained without using welding-over ring processing. It can be manufactured. According to the present invention, it is possible to easily obtain a sheet metal product in which the cylindrical portion protrudes on both the one surface side and the other surface side, and a sheet metal product in which the cylindrical portion protrudes only on one surface side. . Then, the manufactured sheet metal product can be used as a boss for fitting the inner cylindrical portion to a shaft or the like.

Claims

The scope of the claims  1. An inner mold provided in the opening while rotating a sheet metal work having an opening and having an inwardly forked annular protruding piece at the opening edge at a fixed position around the axis of the opening. The inner surface of the inner die is pressed against the annular protrusion by extending the outer surface of the work in the radial direction of the work, and the annular protrusion is extended in the direction along the axis of the opening to thereby extend the cylindrical portion. A method for manufacturing a sheet metal product having a cylindrical portion on an inner periphery, which comprises performing a forming step.  2. The inward bifurcated annular protruding piece is formed by rubbing an opening edge of an opening provided in a plate portion of a sheet metal work at an intermediate portion in a thickness direction thereof. A method for manufacturing a sheet metal product having a cylindrical portion on an inner periphery according to claim 1.  3. While rotating the sheet metal work at a fixed position around the axis of the opening, the inner mold for scraping provided in the opening is moved outward in the radial direction of the work. A step of pressing a V-shaped rubbing surface provided in the inner mold for rubbing against an intermediate portion in the thickness direction of the opening edge of the opening to rub the opening edge. 3. The method for manufacturing a sheet metal product having a cylindrical portion on an inner periphery according to claim 2, wherein the annular protruding piece having an inward bifurcated shape is formed. 4. While rotating the sheet metal work having the opening in a fixed position around the axis of the opening, the inner die provided in the opening is moved outward in the radial direction of the pocket. Up the inner mold surface A method for manufacturing a sheet metal product having a cylindrical portion on an inner periphery, wherein a step of pressing the opening against the opening edge of the work and rolling the cylindrical portion on the opening edge is performed.  5. Prior to rolling the cylindrical portion at the opening edge of the work, a step of thickening the opening edge of the work is performed. Manufacturing method of sheet metal products.  6. The step of increasing the thickness of the opening edge of the work is performed by rotating the work having the opening at a fixed position around the axis of the opening, and disposing the thick wall in the opening. The method according to claim 5, wherein the inner mold is moved outward in the radial direction of the work, so that the thickened molding surface of the inner mold is pressed against the opening edge of the work. Of manufacturing a sheet metal product having a cylindrical portion on the inner periphery thereof.  7. The step of thickening the opening edge of the work is a step of bulging the meat of the opening edge of the work on one side and the other side of the work. 6. The method for manufacturing a sheet metal product having a cylindrical portion on the inner periphery according to 6.  8. The inner periphery according to claim 4, wherein the step of rolling the cylindrical portion is a step of forming the wall of the opening of the work into a cylindrical shape on one side and the other side of the work. A method for manufacturing a sheet metal product having a cylindrical portion. 9. The inner circumference according to claim 7, wherein the step of rolling the cylindrical portion is a step of forming the meat at the opening edge of the work into a cylindrical shape on one side and the other side of the work. Of a sheet metal product having a tubular part Production method.  10. The method according to claim 6, wherein the step of thickening the opening edge of the work is a step of bulging the meat of the opening edge of the work only on one surface side of the work. The described method for manufacturing a sheet metal product having a cylindrical portion on the inner periphery.  11. The step of rolling the cylindrical portion is a step of forming the meat at the opening edge of the work into a cylindrical shape only on one surface side of the work. A method for manufacturing a sheet metal product having the following.  12. The step of rolling the cylindrical portion is a step of forming the meat at the opening edge of the work into a cylindrical shape only on one surface side of the work, wherein the cylindrical portion is formed on the inner periphery according to claim 10. A method for producing a sheet metal product having the following.