JP5608537B2 - Manufacturing method of pipe with flange - Google Patents

Description

  The present invention relates to a flanged pipe manufacturing method in which a flange portion is formed on an end surface of a pipe member used for a bush, a sleeve, or the like.

  There are two methods for forming the shape of the flanged pipe by press working: sheet metal press forming and cold forging. As shown in FIG. 6a, when using sheet metal press molding, drawing, piercing, burring, ironing (one step), and ironing (two steps) are sequentially performed on the material. These consist of five steps. Approximate loads in each process are drawing processing: 430 kN, piercing processing 230 kN, burring / restricting processing: 1010 kN, ironing processing (one step): 230 kN, ironing processing (two steps): 170 kN, and a total of 2070 kN. FIG. 7 shows a cross-sectional shape of the flanged pipe obtained by the sheet metal press molding. The flanged pipe 100 has an R-shaped (arc-shaped) sag at a portion (flange portion opening end) 103 where the lower surface of the flange portion 101 and the inner surface of the pipe portion 102 are continuous.

  In the case of using cold forging, as shown in FIG. 6b, annealing / bonding of the material → forward extrusion process → piercing process → heading process is sequentially performed. These consist of four steps. The approximate load of each process is forward extrusion: 8350 kN, piercing: 1050 kN, heading: 3700 kN, for a total of 13100 kN.

  In addition, there are Patent Documents 1 to 5 as molding methods for suppressing a reduction in the thickness of the pipe portion due to burring. Patent Document 1 discloses a method of forming a thick boss portion by necking and burring a pierced portion. Patent Document 2 describes a method of compressing a cylindrical burring in the axial direction to increase the thickness. In addition, it is disclosed that a process of performing heading, ironing, or the like for reducing the radius of the sag (R shape) of the portion is added to the opening end of the flange portion. Patent Document 3 discloses that the bottom wall in which the lower hole is formed is drawn, and then the lower hole is subjected to burring so as to extrude the bottom wall portion into the cylindrical wall portion to make it thick. Yes. Patent Document 4 discloses that a burring process is performed after the thickness is increased by drawing. Patent Document 5 discloses that a cylindrical portion by burring is subjected to a drawing process.

  Furthermore, there is Patent Document 6 as a method for eliminating sagging and overlapping of corners. For this purpose, it is disclosed that one member of an L-shaped part is compressed in the axial direction from the outer surface while being ironed between the outer surface of the other member.

JP 2000-79438 A JP 2002-239663 A JP 2010-75931 A Japanese Patent Laid-Open No. 10-118722 JP 2009-8126 A JP-A-8-309469

  In order to eliminate the sag (see reference numeral 103 in FIG. 7) generated in the flanged pipe obtained by press molding, further processing such as heading is required. However, when such processing is performed, defects such as pulling and overlapping are likely to occur in the portion 104 on the surface opposite to the flange portion opening end 103.

  On the other hand, sagging does not occur in a flanged pipe formed by cold forging. However, for the forging process, the material requires special lubrication such as annealing and bonding. In addition, since a large molding force and energy are required for molding, a press facility with a large capacity is required.

  In the forming method by burring processing in Patent Documents 1 to 5, sagging is likely to occur at the corner between the inner surface of the pipe portion and the outer surface of the flange portion during processing. And additional work is necessary to remove the sagging. The molding of Patent Document 6 is also performed after the primary molding.

  Then, this invention makes it a subject to provide the method of manufacturing the pipe with a flange which removed the sagging by the simple method with the small forming force.

The flanged pipe manufacturing method according to the present invention (Claim 1) is a flanged pipe manufacturing method, in which a pipe portion is formed by performing burring on the inner peripheral edge of a central hole of a member to be processed. The burring punch is used as an inner mold, and the outer mold applies a compressive force radially inward from the outer periphery of the member to be processed , and the outer mold has a gap between the outer periphery of the burring punch. A tapered surface having a smaller diameter toward the proximal end in the axial direction of the burring punch is formed on the inner surface thereof, and the tube is formed from the side opposite to the burring punch with respect to the member to be processed. By moving the ring-shaped ring punch into the gap relative to the burring punch, the outer mold is moved in the same direction as the burring punch with respect to the member to be processed. It is a pair movement, whereby the compressive force applied to the member to be processed by the tapered surface of the outer mold, characterized in that.

Further, on the outer periphery of the burring punch, a straight surface of the punch parallel to the axial direction and a taper surface of the punch so as to taper from an end of the straight surface are formed, and on the inner peripheral surface of the ring punch, The straight surface of the ring parallel to the straight surface of the punch is spaced from the straight surface of the punch, and the burring punch straight surface and the straight surface of the ring punch are further subjected to ironing (Claim 2 ).

In addition, a straight surface is formed from the lower end of the tapered surface of the outer mold, and the boundary between the straight surface and the tapered surface is the same position in the axial direction from the boundary between the straight surface and the tapered surface on the outer periphery of the burring punch. Or, when the diameter of the opening of the member to be processed is increased by the taper surface of the burring punch, the compressive force is radially inward from the outer periphery of the member to be processed by the outer mold. (Claim 3 ) is preferable.
Furthermore, a tapered surface is formed near the tip of the burring punch, and the angle formed with the axis of the tapered surface of the outer mold is equal to or smaller than the angle formed with the taper surface of the burring punch. What is set is preferable (claim 4).

According to the flanged pipe manufacturing method of the present invention (Claim 1), when the pipe portion is formed by the burring punch, the burring punch is used as the inner mold, and the radially inner portion of the member to be processed by the outer mold is used. Since the compressive force in the direction is applied, the opening end of the flange portion can be filled with the material by flowing the material toward the inner diameter side. Therefore, the occurrence of sagging near the opening end can be prevented. Further, since the material is caused to flow toward the inner diameter side, the plate thickness of the flange portion can be made thicker than the plate thickness before processing.

In such a manufacturing method, the outer mold is a cylindrical shape arranged with a gap between the outer periphery of the burring punch, and the inner surface thereof has a taper that decreases in diameter toward the proximal end side in the axial direction of the burring punch. A surface is formed, and a radial inward compressive stress is applied by moving relative to the member to be processed in the same direction as the burring punch, so that the effect of causing the material to flow toward the inner diameter side is further enhanced.

Then, from the opposite side to the burring punch against members to be processed into said tubular ring punch clearance, by relatively moving with respect to the burring punch, so to impart the compressive force, radially with a simple configuration An inward compression force can be applied.

In addition, a straight surface of the punch parallel to the axial direction and a taper surface of the punch so as to taper from an end of the straight surface are formed on the outer periphery of the burring punch, and a punch surface is formed on the inner peripheral surface of the ring punch. When the straight surface of the ring parallel to the straight surface is spaced from the straight surface of the punch, and the ironing is further performed by the straight surface of the burring punch and the straight surface of the ring punch ( According to the second aspect of the present invention, the pipe portion can be formed by ironing the straight surface of the burring punch and the straight surface of the ring punch. Since all processing can be performed at once, the molding force can be reduced.

In addition, a straight surface is formed from the lower end of the tapered surface of the outer mold, and the boundary between the straight surface and the tapered surface is the same position in the axial direction from the boundary between the straight surface and the tapered surface on the outer periphery of the burring punch. Or, when the diameter of the opening of the member to be processed is increased by the taper surface of the burring punch, the compressive force is radially inward from the outer periphery of the member to be processed by the outer mold. when granting (claim 3), when the burring punch increase the diameter of the opening of the member to be processed, to compress the outer periphery of the outer mold member to be processed by the tapered surface of the inwardly sagging The resulting site can be filled with material.

FIG. 1 shows a schematic view of the production method of the present invention. FIG. 2 is a schematic side view of an apparatus used in the production method of the present invention. FIG. 3 is a process diagram showing details of the manufacturing method. FIG. 4 is a partially enlarged view of steps S1 to S4 in FIG. FIG. 5 is a partially enlarged view of steps S5 to S7 in FIG. FIG. 6a is a conventional schematic process diagram showing a method of forming a flanged pipe using sheet metal press working, and FIG. 6b is a conventional schematic process diagram showing a method of forming a flanged pipe using cold forging. FIG. 7 is a cross-sectional view showing an example of a flanged pipe obtained by a conventional forming method.

  The outline of the manufacturing method (henceforth, manufacturing method) of the flanged pipe of this invention is demonstrated using FIG. In the manufacturing method 10, a member 13 to be processed (hereinafter referred to as a semi-finished product) 11 is subjected to a step 13 of burring, and in the step 13, a radially inward compressive force is applied from the outer periphery of the semi-finished product 11. The process 14 which performs the process to perform is performed, and the flanged pipe 12 is obtained.

  As shown in the figure, the semi-finished product 11 processed by the present manufacturing method 10 is a plate-like member having a central hole 11a formed at the center. The outer shape and the central hole 11a are, for example, circular.

  The flanged pipe 12 includes a pipe portion 12a and a flange portion 12b extending outward from the open end of the pipe portion 12a. The thickness T of the flange portion 12 b is thicker than the plate thickness t of the semi-finished product 11.

  FIG. 2 shows an apparatus (mold) used in the manufacturing method 10 (see FIG. 1). The apparatus 1 includes a burring punch (inner die) 2 for performing burring and an outer die 3 (hereinafter referred to as a die) arranged concentrically with a gap 1a between the outer periphery of the burring punch. I have. Further, a cylindrical ring punch 4 is provided so as to be movable relative to the burring punch from the side opposite to the burring punch 2 to the gap 1a with respect to the semi-finished product 11. Further, a knockout block 5 is provided so as to be movable relative to the burring punch so that the ring punch 4 and the tip end face each other.

  The burring punch 2 is a cylindrical member, and its peripheral surface has a tapered shape in which a straight surface 2b parallel to the axial direction and a tapered surface 2a continuous from the straight surface 2b are formed. In the figure, the angle formed with the axis of the tapered surface 2a of the burring punch is indicated by the symbol α. The cross-sectional shape of the burring punch 2 may be a polygonal shape in addition to a circular shape.

  The die 3 is attached together with the burring punch 2 to, for example, a bolster (not shown) of a press machine, and the ring punch 4 is attached to a slide (not shown). The semi-finished product 11 is pushed by the lowering of the ring punch 4 attached to the slide. Thereby, the die 3 is movable relative to the semi-finished product 11. The die 3 has a tapered surface 3a formed of a conical surface that tapers from the tip end in the axial direction of the burring punch 2 toward the base end side on the inner surface on the upper side thereof. On the other hand, the lower inner surface is formed with the straight surface 3b of the die 3 so as to face the straight surface 2b of the burring punch from the lower end of the tapered surface 3a, and continues to the lower open end. Note that the cross-sectional shape of the die 3 may be a polygonal shape in addition to a circular shape.

Further, the angle β formed with the axis of the taper surface 3a of the die is appropriately processed by the burring process 13 (see steps S2 to S4 in FIG. 4), so that the taper surface 2a of the burring punch is formed. It is preferable to set it equal to or smaller than the angle α. Thereby, the part near the center hole 11a of the semifinished product 11 is expanded in diameter by the tapered surface 2a of the burring punch (becomes the pipe portion 12a), and the part outside the semifinished product 11 (the side far from the center hole 11a) is It is compressed inward by the tapered surface 3a of the die.
Further, by placing the ring punch 4 closer to the die 3 of the semi-finished product 11, the side near the center hole 11a of the semi-finished product 11 can be expanded in diameter by the tapered surface 2a of the burring punch. 13, the pipe portion 12a can be appropriately processed (see steps S2 to S4 in FIG. 4).
Furthermore, it is preferable that the boundary (see reference numeral 3c) between the taper surface 3a and the straight surface 3b of the die is arranged at the same height as or below the boundary 2c of the burring punch. When the burring punch expands the diameter of the central hole 11a of the semi-finished product, the outer periphery of the semi-finished product 11 is compressed inward by the taper surface 3a of the die 3, and the inward material flow of the semi-finished product 11 is formed. This is to make it smooth.

The ring punch 4 is a cylindrical member that is passed through the gap 1 a and is arranged concentrically with the openings of the burring punch 2 and the die 3. Here, the gap 1a is a gap from the taper surfaces 2a and 3a of the burring punch 2 and the die 3 to the straight surfaces 2b and 3b. Both the cylindrical inner and outer surfaces of the ring punch 4 are formed in parallel with the straight surface 2b of the burring punch. Further, a gap 1b is formed between the inner peripheral surface of the ring punch 4 and the straight surface 2b of the burring punch. A tapered surface 4 a is formed on the inner surface side of the tip of the ring punch 4 so as to be inclined inwardly as it goes upward in the axial direction. Thereby, the taper surface corresponding to the taper surface 4a is formed also in the pipe part 12a of the pipe 12 with a flange.

  Moreover, it is preferable that the arrangement of the ring punch 4 with respect to the semi-finished product 11 is outside the center position in the radial direction from the opening edge of the center hole 11a to the outer peripheral edge. That is, it is for forming the pipe part 12a by the appropriate burring process 13. FIG. Even in such a case, the angle β of the taper surface 3a of the die may be set larger than the angle α of the taper surface 2a of the burring punch (gradiently inclined), contrary to the above.

  The knockout block 5 is a cylindrical member that is passed between the straight surface 2b of the burring punch and the straight surface 2b of the die, and is disposed so as to be movable relative to the burring punch 2 and the die 3. The knockout block 5 is pushed up and down by a knockout pin 6 disposed below the knockout block 5.

  Next, how the flanged pipe 12 is manufactured by the manufacturing method 10 will be described in detail with reference to FIGS. In the step S1 shown in FIG. 3, the semi-finished product 11 is placed in a state where the columnar portion on the upper side of the tapered surface 2a of the burring punch is passed through the central hole 11a (see FIG. 4). The ring punch 4 is arranged on the upper surface side of the semi-finished product 11. In the figure, the ring punch 4 is in contact with the upper surface of the semi-finished product 11 in the vicinity of the upper surface of the burring punch 2, but at the top dead center of the press machine, it is separated from the flanged pipe 12 as shown in step S7. 2 is moving above. Further, the arrangement of the ring punch 4 and the burring punch 2 can be turned upside down. Further, the semi-finished product 11 is previously formed with a circular central hole 11a by piercing or the like.

  Next, in step S <b> 2, the ring punch 4 moves downward with respect to the burring punch 2 and the die 3. When the semi-finished product 11 is pushed into the gap 1a by the ring punch 4, the semi-finished product 11 is curved upward at the portion around the central hole 11a by the tapered surface 2a (see FIG. 4) of the burring punch 2 (arrow W). ). At the same time, a compressive force (see symbol P) inward from the taper surface 3a of the die 3 is applied to the semi-finished product 11 from the outer periphery. As a result, a radially inward (arrow M) material flow occurs in the semi-finished product 11.

  Next, in step S3, when the semi-finished product 11 is pushed deeper by the ring punch 4, the inner circumference of the portion that becomes the tapered surface 2a of the burring punch 2 (see FIG. 4) and the pipe portion 12a of the semi-finished product 11 (see FIG. 1). Increases the contact area. For this reason, the reaction force P of the same magnitude acts in the opposite direction to the compression force P from the taper surface 3a of the die from the taper surface 2a of the burring punch. As a result, the material flow M is regulated, and the flange opening end (portion 15) is filled with the material, so that the R-shaped sagging (see symbol 103 in FIG. 7) is reduced. And the said material flow M arises with the compressive force of radial direction, and plate | board thickness T 'becomes larger than the thickness t (S1, refer FIG. 1) of the semi-finished product 11 before a process.

  In step S4, the ring punch 4 pushes the semi-finished product 11 further. As a result, both the inner and outer surfaces of the part that becomes the flange portion 12b (see FIG. 1) of the semi-finished product 11 reach the boundaries 2c and 3c (see FIG. 4) of the burring punch 2 and the die 3, and the gap 1a is straight. It is narrowed between the surfaces 2b and 3b. Thereby, ironing is performed and the outer diameter dimension of the flange portion 12b is set to a predetermined value. This ironing process fills the reduced sagging (the portion indicated by reference numeral 15 in S3) with material, and the sagging is corrected.

  In step S5, after the flange portion 12b passes through the boundaries 2c and 3c, the pipe portion 12a passes through the boundaries 2c and 3c (see FIG. 5). At this time, the pipe portion 12a is ironed by the inner surface of the ring punch 4 and the straight surface 2b of the burring punch. Thereby, the thickness is reduced and the length is increased. In addition, the shaping | molding force to process S1-S5 is about 700 kN.

  In step S6, the flange portion 12b is sized by the ring punch 4 and the knockout block 5 at the bottom dead center of the press machine, and the bottom surface of the flange portion 12b is formed into a flat surface. In addition, the molding force of this process is about 900 kN.

  In step S7, the knockout block 5 is raised by the knockout pin 6, and the flanged pipe 12 as a product is taken out from the gap 1a between the burring punch 2 and the die 3.

1 Equipment (mold)
1a Clearance between burring punch and outer die 1b Clearance between burring punch and ring punch 2 Burling punch 2a Tapered surface of burring punch 2b Straight surface of burring punch 2c Bounding of burring punch 3 Outer die (die)
3a Tapered surface 3b of outer die (die) Straight surface 3c of outer die (die) 4 Boundary of die 4 Ring punch 4a Tapered surface 5 of ring punch Knockout block 6 Knockout pin 10 Manufacturing method 11 Member to be processed (semi-finished product)
11a Central hole 12 Flange pipe 12a Pipe part 12b Flange part 13 Burring process 14 Compression process 15 Sag P Compressive force M Material flow t Semi-finished sheet thickness T Flange pipe flange thickness α Burring punch taper Surface angle β Die taper surface angle

Claims (4)

A method of manufacturing a flanged pipe,
When forming the pipe part by burring the inner peripheral edge of the center hole of the member to be processed, the outer ring is compressed radially inward from the outer periphery of the member to be processed using the burring punch as the inner mold To give power ,
The outer mold is a cylindrical shape arranged with a gap between the outer periphery of the burring punch, and a taper surface having a smaller diameter toward the proximal end in the axial direction of the burring punch is formed on the inner surface thereof,
The cylindrical ring punch is moved relative to the burring punch from the opposite side of the burring punch with respect to the member to be processed, and the outer die is processed in the same direction as the burring punch. Move relative to the member to be
Thereby, the manufacturing method of the pipe with a flange which provides the said compression force to the member which should be processed by the taper surface of the said outer type | mold . On the outer periphery of the burring punch, a straight surface of the punch parallel to the axial direction, and a taper surface of the punch so as to taper from an end of the straight surface,
On the inner peripheral surface of the ring punch, a straight surface of the ring parallel to the straight surface of the punch is formed so as to be spaced from the straight surface of the punch,
Wherein the the straight surface and the straight surface of the ring punch burring punch, flanged pipe manufacturing method of further facilities to claim 1, wherein the ironing. A straight surface is formed from the lower end of the tapered surface of the outer mold,
The boundary between the straight surface and the taper surface is the same position in the axial direction as the boundary between the straight surface and the taper surface on the outer periphery of the burring punch, or the base end side from it.
3. With a flanged flange according to claim 2 , wherein when the diameter of the opening of the member to be processed is expanded by the tapered surface of the burring punch, a compressive force is applied radially inward from the outer periphery of the member to be processed by the outer mold. Pipe manufacturing method. A tapered surface is formed near the tip of the burring punch,
4. The flanged pipe according to claim 1, wherein an angle formed with the axis of the outer tapered surface is set to be equal to or smaller than an angle formed with the tapered surface of the burring punch. 5. Manufacturing method.

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