JP2017185531A - Manufacturing method and manufacturing apparatus for expanded diameter pipe parts - Google Patents

Abstract

A general portion having a predetermined diameter and a shaft formed at the tip of a cylindrical body and having a diameter expanded to a predetermined size with respect to the general portion and eccentric at a predetermined crossing angle with respect to the axial direction of the general portion. An enlarged diameter pipe having an enlarged diameter portion having a direction and a varying portion formed between the general portion and the enlarged diameter portion and expanding at a predetermined inclination angle from the general portion toward the distal end, arranged in the axial direction. A part manufacturing method and manufacturing apparatus are provided. A concentric tube expansion process for manufacturing a first intermediate molded product by performing concentric tube expansion processing on a cylindrical body with a concentric tube expansion punch, and an eccentric tube expansion punch having a shape that matches the change part are installed in the mold. an eccentric tube expanding step of pressing into the first intermediate molded product to produce a second intermediate molded product having a shape of a changed part and having an end portion expanded more than the diameter-expanded pipe part as the final product; a diameter reducing step of pressing a diameter reducing punch having a shape that matches the diameter portion to the outside of the end portion of the second intermediate molded product. [Selection drawing] Fig. 2

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for a diameter-expanded pipe component.

  Generally, parts that have been subjected to pipe expansion processing (mouth expansion processing) are used for exhaust system parts of automobiles and motorcycles. These are desired to be integrally formed from the viewpoint of welding-less and cost reduction.

  On the other hand, for example, a special shape is required, such as having a tip portion that is eccentric and expanded in diameter at the end of the metal tube.

  As a specially-shaped tube-expanded part, a general part having a predetermined diameter and a tip of the cylindrical body are formed and the diameter of the general part is increased to a predetermined size. A diameter-enlarged portion having an axial direction that is eccentric with respect to a predetermined crossing angle, and a change portion that is formed between the general portion and the enlarged-diameter portion and expands to a predetermined inclination angle from the general portion toward the tip portion. There is an expanded pipe part having the

  As a method for processing a special shape in a metal tube, as disclosed in Patent Documents 1 to 3, a forming method for performing bulge forming (hydroforming) has been proposed.

  Further, as disclosed in Patent Documents 4 to 6, spinning processing, which is one method of plastic processing in which a tubular material is pressed against a rotating mold with a processing roller or spatula, is proposed.

JP 2000-225422 A JP 2004-268096 A JP 2000-045767 A Japanese Patent Laid-Open No. 2000-190038 Japanese Patent Laid-Open No. 2003-010935 JP 2009-018342 A

  However, in bulge forming and spinning processing, in addition to the large and expensive processing equipment, the cycle time is long, the productivity is low, and in the case of a molded product with a large degree of processing at the end, the thickness of the molded product is increased. There is a problem that variations occur and cracks and wrinkles are likely to occur. In particular, in the processing of high-strength materials and welded pipes, it is difficult to manufacture a molded product having a large end portion processing degree by bulge forming or spinning processing.

  Under such circumstances, there is a demand for a manufacturing method and a manufacturing apparatus capable of manufacturing a diameter-expanded pipe part having a large end portion processing degree with low cost and low tact time with high productivity.

  The objective of this invention is providing the manufacturing method and manufacturing apparatus of the said enlarged diameter pipe component.

  The present invention is listed below.

(1) A cylindrical body, which is a metal material, is processed to form a general portion having a predetermined diameter and a tip of the cylindrical body, and the diameter is increased to a predetermined size with respect to the general portion. A diameter-enlarged portion having an axial direction decentered at a predetermined crossing angle with respect to the axial direction of the general portion, and the diameter-expanded portion formed between the general portion and the diameter-expanded portion. A method of manufacturing a diameter-expanded pipe component having a change portion that expands to a predetermined inclination angle toward the axial direction,
At least one concentric tube expansion step for producing a first intermediate molded product by pushing a concentric tube expansion punch in the axial direction of the tube body and performing concentric tube expansion on the tube body;
The concentric tube expansion process in the first intermediate molded product in which an eccentric tube expansion punch having an outer surface shape that matches the inner surface shape of the changing portion is installed in a mold having an inner surface shape that matches the outer surface shape of the changing portion is performed. By pushing in the axial direction of the portion that has been performed and performing eccentric tube expansion processing on the first intermediate molded product, the end portion is expanded than the expanded tube component that has the shape of the changed portion and is the final product. An eccentric tube expansion process for manufacturing the second intermediate molded product,
A diameter-reducing punch having an inner surface shape that matches the outer surface shape of the enlarged-diameter portion is pushed into the outer side of the end portion of the second intermediate molded product to reduce the diameter of the end portion of the second intermediate molded product. A diameter-reducing processing step of performing (aperture processing).

  (2) The diameter-reducing punch is reduced in diameter by being pushed in from the outside of the end portion of the second intermediate molded product in the axial direction of the second intermediate molded product (1) ) Method for producing a diameter-expanded pipe part described in the item.

  (3) In the concentric tube expanding step, a concentric tube expanding punch having a punch half angle larger than the inclination angle of the changing portion, an outer diameter larger than an inner diameter of the cylindrical body and smaller than an inner diameter of the changing portion, The method of manufacturing a diameter-expanded pipe component according to (1) or (2), wherein the cylinder is subjected to concentric tube expansion processing at a tube expansion rate of 25% or less by being pushed in the axial direction of the cylinder.

  In the present invention, the “expansion ratio” refers to an expansion ratio based on the outer diameter of the expanded section before the expansion process in each step. That is, the tube expansion ratio is {(outer diameter of the expanded portion after tube expansion in each step−outer diameter of the expanded portion before tube expansion in each step) / outer diameter of the expanded portion before tube expansion in each step} × 100 It is calculated as (%).

Alternatively, when the outer diameter of the expanded portion before tube expansion processing in each step is d ₀ and the outer diameter d ₁ of the expanded portion after tube expansion processing in each step, the expansion ratio = {(d ₁ −d ₀ ) / d ₀ } × 100 (%).

  It should be noted that at least one concentric tube expansion process may be provided, but depending on the shape of the final product, a plurality of processes may be used. For example, when processing the concentric tube expansion process in three stages, it can be molded as follows.

  In the method for manufacturing a diameter-expanded pipe component according to any one of (1) to (3), the concentric tube expansion process includes a first concentric tube expansion process, a second concentric tube expansion process, and a third concentric tube expansion process. .

  In the first concentric tube expanding step, a first concentric tube expanding punch having a punch half angle larger than the inclination angle of the changing portion and an outer diameter larger than an inner diameter of the cylindrical body and smaller than an inner diameter of the changing portion. By pushing in the axial direction of the cylindrical body, the cylindrical body is expanded at a tube expansion rate of 25% or less to produce the intermediate product 1a.

  The second concentric tube expanding step has a punch half angle larger than the inclination angle and a second outer diameter that is larger than an inner diameter at an axial end portion of the intermediate molded product of the 1a and smaller than an inner diameter of the changing portion. The first expansion tube is expanded to a position before the first concentric tube expansion punch in the axial direction of the first a intermediate molded product to the position before the first concentric tube expansion punch. The intermediate molded product of 1b is manufactured.

  Further, the third concentric tube expanding step has a punch half angle larger than the inclination angle and an outer diameter that is larger than an inner diameter at an axial end portion of the intermediate molded product of the 1b and smaller than an inner diameter of the changing portion. By pushing the third tube expansion punch in the axial direction of the 1b intermediate molded product to a position before the second concentric tube expansion punch, the 1b intermediate molded product is expanded at a tube expansion rate of 25% or less. The intermediate molded product 1c is manufactured.

  And the eccentric tube expansion punch having an outer surface shape that matches the inner surface shape of the changing portion is installed in the mold having the inner surface shape that matches the outer surface shape of the changing portion, and the concentric tube expanding in the intermediate molded product of the 1c By pushing in the axial direction of the processed part and performing eccentric tube expansion processing on the 1c intermediate molded product, the end portion is expanded than the expanded tube component that has the shape of the changed portion and is the final product. The second intermediate molded product is manufactured.

  In addition, it is also one aspect preferably used in the present invention that the first concentric tube expansion punch, the second concentric tube expansion punch, and the third concentric tube expansion punch have the same punch half angle.

  (4) The diameter-expanded tube described in any one of items (1) to (3), further comprising a step of cutting a thinned portion formed at a tip of the diameter-expanded portion. A manufacturing method for parts.

In the present invention, the “thinned portion” refers to a case where the thickness of the raw pipe before diameter expansion processing (also referred to as a cylindrical body in the present invention) is compared with the thickness of the diameter expansion pipe component that is the final product. The thickness reduction part. Specifically, the thickness reduction rate = {(thickness before diameter expansion processing−thickness after diameter expansion processing) / thickness before diameter expansion processing} × 100 (%). Alternatively, when the thickness of the raw steel pipe before squeeze forming is t ₀ and the thickness after the squeeze forming at the axial end of the end splayed steel pipe is t ₁ , the thickness reduction rate = {(t ₀₋ t ₁ ) / t ₀ } × 100 (%). It represents that the thickness is reduced as the rate of thickness reduction increases.

  (5) The method for manufacturing a diameter-expanded pipe component described in any one of items (1) to (4), wherein the cylindrical body is a welded tube.

  (6) The method for manufacturing a diameter-expanded pipe component described in any one of items (1) to (5), wherein the material has a tensile strength of 590 MPa or more.

  (7) The expanded pipe according to any one of (1) to (6), wherein the expanded pipe component is an engine exhaust system muffler or a catalyst case of an automobile or a motorcycle. A manufacturing method for parts.

(8) A cylindrical body, which is a metal material, is processed to form a general portion having a predetermined diameter and a tip of the cylindrical body, and the diameter is increased to a predetermined size with respect to the general portion. A diameter-enlarged portion having an axial direction decentered at a predetermined crossing angle with respect to the axial direction of the general portion, and the diameter-expanded portion formed between the general portion and the diameter-expanded portion. An apparatus for manufacturing a diameter-expanded pipe component having a change part that expands to a predetermined inclination angle toward the axial direction,
At least one concentric tube expansion punch for producing a first intermediate molded product by being pushed in the axial direction of the tube body and performing concentric tube expansion processing on the tube body;
A mold having an inner surface shape that matches the outer surface shape of the change portion;
It has an outer surface shape that matches the inner surface shape of the changing portion, and is pushed in the axial direction of the portion where the concentric tube expansion processing is performed in the first intermediate molded product installed in the mold, An eccentric tube expansion punch for producing a second intermediate molded product having a shape of the change portion and having an end portion expanded from the diameter-expanded tube component as a final product by performing an eccentric tube expansion process on the intermediate molded product; ,
It has an inner surface shape that matches the outer surface shape of the diameter-enlarged portion, and is pressed to the outside of the end portion of the second intermediate molded product to reduce the diameter of the end portion of the second intermediate molded product. An apparatus for manufacturing a diameter-expanded pipe part, comprising:

  (9) The diameter-expanded pipe component described in (8), wherein the diameter-reduced punch is pushed in from the outside of the second intermediate molded product in the axial direction of the second intermediate molded product. Manufacturing equipment.

  (10) The concentric tube expanding punch has an outer diameter that is larger than the inclination angle of the changing portion and larger than the inner diameter of the cylindrical body and smaller than the inner diameter of the changing portion, The apparatus for manufacturing a diameter-expanded pipe component according to item (8) or (9), wherein the tubular body is expanded in an axial direction by being expanded in a tube expansion rate of 25% or less.

  (11) The diameter expansion described in any one of items (8) to (10), further comprising a cutting means for cutting a thinned portion formed at a tip of the diameter expansion portion. Pipe parts manufacturing equipment.

  (12) The apparatus for manufacturing a diameter-expanded pipe component according to any one of items (8) to (11), wherein the material is a welded tube.

  (13) The apparatus for manufacturing a diameter-expanded pipe component according to any one of items (8) to (12), wherein the material has a tensile strength of 590 MPa or more.

  (14) The diameter expansion pipe described in any one of items (8) to (13), wherein the diameter expansion pipe part is an engine exhaust system muffler or a catalyst case of an automobile or a motorcycle. Parts manufacturing equipment.

  According to the present invention, the general portion having a predetermined diameter, and formed at the tip of the cylindrical body and expanded to a predetermined size with respect to the general portion, the predetermined crossing angle with respect to the axial direction of the general portion And an enlarged diameter portion having an axial direction that is eccentric with each other, and a changing portion that is formed between the general portion and the enlarged diameter portion and that is enlarged from the general portion to the tip portion at a predetermined inclination angle, is aligned in the axial direction. It is possible to provide a manufacturing method and a manufacturing apparatus for an expanded pipe component having

  In addition, according to the manufacturing method and the manufacturing apparatus of the present invention, a tubular material can be set in a predetermined mold, and the mouth drawing process can be performed with a predetermined diameter-expanding punch. Since there is no need to use a material and there is no need to replace the material, the process and cost can be reduced. Furthermore, since it is possible to prevent the material and the axial center of the diameter-expansion punch from being misaligned, the product dimension and shape can be stabilized, and the product yield can be improved.

FIG. 1 is a cross-sectional view showing an example of a diameter-expanded pipe component manufactured according to the present invention. 2 (a) to 2 (e) are explanatory views showing a preferable manufacturing process of the present invention over time. FIG. 3 is a contour diagram showing the thinning rate of the expanded diameter pipe part manufactured according to the present invention. FIG. 3 (a) is a front view of the expanded diameter pipe part, and FIG. FIG. 3C is a top view and FIG. 3C is a bottom view of the expanded pipe component.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

1. FIG. 1 is a cross-sectional view showing an example of a diameter expansion pipe part manufactured according to the present invention.

  As shown in FIG. 1, the diameter-expanded pipe part P3 manufactured according to the present invention includes a general part P31 having a predetermined diameter, a change part P32, and a diameter-expanded part P33 side by side in the axial direction.

  The enlarged-diameter portion P33 is formed at the tip of the cylindrical body and is enlarged to a predetermined size with respect to the general portion P31, and has an axial direction that is eccentric with a predetermined crossing angle θ with respect to the axial direction of the general portion P31. Have.

  The crossing angle θ is preferably in the range of 5 to 30 °. If it is in this range, the formation of the thinned portion of the expanded pipe part P3 can be suppressed, the product breakage can be suppressed, and the yield reduction can be greatly suppressed.

  If the crossing angle θ is less than 5 °, it is no longer possible to obtain a diameter-expanded pipe part having a large end workability, which is the object of the present invention, and the present invention can be manufactured not by the present invention but by the prior art. There is no. On the other hand, if the crossing angle θ exceeds 30 °, cracks may occur in the middle of processing, and it is difficult to manufacture a diameter-expanded pipe part P3 having sufficient dimensional accuracy without cracking.

  The changing part P32 is formed between the general part P31 and the enlarged diameter part P33 and is enlarged to a predetermined inclination angle (α1, α2) from the general part P31 toward the enlarged diameter part P33. Since the inclination angle of the changing portion is not constant in the circumferential direction of the diameter expansion pipe part P3, in FIG. 1, the inclination angles α1 and α2 are shown by the cross-sectional view of the diameter expansion pipe part P3.

  In addition, the inclination angles α1 and α2 are preferably set so that the final tube expansion rate from the material is 100% or less. If it is in this range, the formation of the thinned portion of the expanded pipe part P3 can be suppressed, the product breakage can be suppressed, and the yield reduction can be greatly suppressed.

2. Manufacturing Apparatus According to the Present Invention FIGS. 2A to 2E are explanatory views showing a preferable manufacturing process of the present invention over time.

  As shown in FIGS. 2A to 2E, the manufacturing apparatus 0 according to the present invention includes a concentric tube expanding punch 1, an eccentric tube expanding punch 2, a reduced diameter punch 3, and a mold 4.

(2-1) Concentric tube expansion punch 1
As shown in FIG. 2A, the concentric tube expansion punch 1 is pushed in the axial direction of the cylinder body P from the end portion Pa side of the tube body P on the tube expansion hole side to perform concentric tube expansion processing on the cylinder body P. The first intermediate molded product P1 is manufactured by

  The concentric tube expansion punch 1 has an inclined portion 11 having an inclination angle β (hereinafter referred to as “punch half angle β”) larger than a predetermined inclination angle α in a change portion P32 of a desired expanded tube component P3 manufactured in the present invention. Is preferably provided at the tip of the cylinder press-fitting side. Here, the inclination angle α indicates an average value at each position in the circumferential direction of the cross section of the changing portion P32.

  The concentric tube expanding punch 1 preferably has an outer diameter d that is larger than the inner diameter of the cylindrical body P and smaller than the inner diameter of the changing portion P32. The tube expansion rate by one concentric tube expansion punch 1 is preferably 25% or less, more preferably 20 to 25%.

  The punch half angle β can be appropriately adjusted according to the size of the inclination angle α and the length of the changing portion P32. For example, the punch half angle β is larger than the inclination angle α and is preferably in the range of 30 ° to 60 °. When the punch half angle β is less than 30 °, the metal material is insufficiently pushed and cracks are likely to occur in the changed portion. As the inclination angle β increases, the load due to the pressing of the punch is too large and buckling is likely to occur. If β exceeds 60 °, curling deformation occurs such that the end on the tube expansion hole side is wound outside, which is not preferable.

  In the above description, the case of having one concentric tube expansion punch 1 is taken as an example. However, at least one concentric tube expansion punch may be provided, and a plurality of concentric tube expansion punches may be provided depending on the final product shape. For example, the case of having three concentric tube expansion punches will be described with reference to FIGS. 2 (a) to 2 (c).

  A first concentric tube expanding punch 1 shown in FIG. 2 (a), a second concentric tube expanding punch 1-1 shown in FIG. 2 (b), and a third concentric tube expanding punch 1-2 shown in FIG. 2 (c). Is used.

  As shown in FIG. 2 (a), the first concentric tube expansion punch 1 has a punch half angle β1 larger than a predetermined inclination angle α in a change portion P32 of a desired diameter expansion tube component P3 manufactured in the present invention. An inclined portion 11a is provided at the tip of the cylindrical body press-fitting side. Moreover, it is preferable that the 1st concentric tube expansion punch 1 has the outer diameter d1 larger than the internal diameter of the cylinder P, and smaller than the internal diameter of the change part P32.

  The first concentric tube expansion punch 1a is expanded from the end of the tube body P on the tube expansion hole side in the axial direction of the tube body P, thereby expanding the tube body P to form the first a intermediate molded product P1a. To manufacture.

  The tube expansion rate from the cylinder P by the first concentric tube expansion punch 1a is preferably 25% or less, and more preferably in the range of 20 to 25%.

  As shown in FIG. 2 (b), the second concentric tube expanding punch 1-1 has a punch half angle β2 larger than a predetermined inclination angle α in the change portion P32 of a desired expanded tube component manufactured in the present invention. The inclined portion 11b is provided at the front end of the first-a intermediate molded product P1a. The second concentric tube expanding punch 1-1 preferably has an outer diameter d2 that is larger than the inner diameter at the axial end portion of the 1a intermediate molded product P1a and smaller than the inner diameter of the changing portion P32.

  The second concentric tube expanding punch 1-1 is located in front of the pushing position of the first concentric tube expanding punch 1 in the axial direction of the 1a intermediate molded product P1a from the end of the 1a intermediate molded product P1a on the tube expansion hole side. By being pushed to the position, the 1a intermediate molded product P1a is expanded to produce the 1b intermediate molded product P1b.

  The tube expansion rate from the 1a intermediate molded product P1a by the second concentric tube expansion punch 1b is preferably 25% or less, and more preferably in the range of 20 to 25%.

  As shown in FIG. 2 (c), the third concentric tube expansion punch 1-2 has a punch half angle β3 larger than a predetermined inclination angle α in the change portion P32 of the desired diameter expansion tube component manufactured in the present invention. The inclined portion 11c is formed at the tip of the 1b intermediate molded product P1b on the press-fitting side. The third concentric tube expanding punch 1-2 preferably has an outer diameter d3 that is larger than the inner diameter at the axial end of the 1b intermediate molded product P1b and smaller than the inner diameter of the changing portion 32.

  The third concentric tube expansion punch 1-2 is located before the push-in position of the second concentric tube expansion punch from the end of the 1b intermediate molded product P1b on the tube expansion hole side toward the axial direction of the 1b intermediate molded product P1b. By being pushed to the position, the 1b intermediate molded product P1b is expanded to produce the 1c intermediate molded product P1c.

  The tube expansion rate from the 1b intermediate molded product P1b by the third concentric tube expansion punch 1c is preferably 25% or less, and more preferably in the range of 20 to 25%.

  The punch half angles β1, β2, and β3 can be appropriately adjusted according to the size of the inclination angle α and the length of the changing portion P32. For example, the punch half angle β3 is larger than the inclination angle α and is preferably in the range of 30 ° to 60 °. When the punch half angle β2 is less than 30 °, the metal material is not pushed in easily, and cracks are likely to occur in the changed portion. If β2 exceeds 60 °, curling deformation occurs such that the end portion on the tube expansion hole side is wound outside, which is not preferable.

  The relationship between the punch half angles β1, β2, and β3 of the concentric tube expanding punches 1a to 1b is not particularly limited. It can be appropriately set according to the shape of the desired expanded diameter pipe part changing portion. For example, β1 = β2 = β3, β1 <β2 <β3, or β1 <β2> β3 may be used.

  About the eccentric tube expansion punch 2 and the metal mold | die 4, the below-mentioned thing same as the case where it has one concentric tube expansion punch 1 can be used.

  As described above, it is preferable to use a plurality of concentric tube expanding punches because the thickness reduction rate in the changed portion P32 and the expanded portion P33 of the expanded tube component formed into a desired shape can be reduced.

(2-2) Eccentric tube expansion punch 2
As shown in FIG. 2D, the eccentric tube expansion punch 2 has an outer surface shape that matches the inner surface shape of the changed portion P32 of the desired diameter-expanded tube component P3. The eccentric tube expansion punch 2 is pushed in the axial direction of the portion where the concentric tube expansion process has been performed in the first intermediate molded product P1 or the first intermediate molded product P1c installed in the mold 4, and the first intermediate molded product By performing an eccentric tube expansion process on the P1 or 1c intermediate molded product P1c, the second intermediate molded product having the shape of the changing portion P32 and the end portion of which is wider than the expanded pipe component P3 which is the final product. P2 is manufactured.

  Further, as shown in FIG. 2 (d), it may have an outer surface shape that matches not only the inner surface shape of the changing portion P32 but also a part of the inner surface shape of the enlarged diameter portion P33. In that case, the shape of the reduced diameter punch 3 to be described later may also have an inner surface shape that matches the outer surface shape of the enlarged diameter portion P33 in a portion other than the partial shape of the enlarged diameter portion P33 formed by the eccentric tube expansion punch 2. .

  Moreover, the eccentric tube expansion punch 2 may be divided | segmented into plurality depending on the shape of the change part P32.

(2-3) Reduced diameter punch 3
As shown in FIG. 2 (e), the diameter-reducing punch 3 has an inner surface shape that matches the outer surface shape of the diameter-expanded portion P33 of the desired diameter-expanded pipe component. The diameter-reducing punch 3 is pushed to the outside of the end portion of the second intermediate molded product P2 where the eccentric tube expansion has been performed, and the diameter reduction punch 3 is subjected to diameter reduction processing at the end of the second intermediate molded product P2. The expanded pipe part P3 is manufactured.

  The reduced diameter punch 3 is preferably pushed in the axial direction from the outside into the end of the second intermediate molded product P2. When the diameter-reducing punch 3 is pushed axially into the end of the second intermediate molded product P2, it is preferable because the diameter-reducing process can be performed without moving the mold 4. Further, even when the mold 4 is moved, it is only necessary to design the mold 4 to move outward from the second intermediate molded product P2 only at a part of the portion where the reduced diameter punch 3 is pushed. It can be manufactured by a simple process.

(2-4) Mold 4
The mold 4 can have the second intermediate molded product P2 disposed therein, and has an inner surface shape that matches the outer surface shape of the changed portion P32 of the expanded diameter pipe component P3 (the shape of the final product).

  Although FIG. 2 shows a mode in which the mold 4 is divided into an upper mold 4a and a lower mold 4b, the present invention is not limited to this mode, and even if it is integrated, it is further divided into a plurality of parts. It may be.

  It is preferable to provide a plate or the like at the end opposite to the end on the tube expansion hole side so that the end of the mold 4 is closed.

  Moreover, the manufacturing apparatus of this invention may further be equipped with the cutting means which cut | disconnects the thinning part formed in the front-end | tip of the enlarged diameter part P33 of the enlarged diameter pipe component P3.

  FIG. 3 is a contour diagram showing the thinning rate of the expanded diameter pipe part P3 manufactured according to the present invention. FIG. 3 (a) is a front view of the expanded diameter pipe part P3, and FIG. 3 (b) is the expanded diameter pipe. FIG. 3C is a top view of the part P3, and FIG. 3C is a bottom view of the expanded pipe part P3. In Fig.3 (a)-FIG.3 (c), it shows that thinning is so large that the positive value of thinning rate is large.

  For example, a portion having a large thickness reduction (thickness reduction rate: 10 to 20%) is present at the distal end portion of the diameter-expanded pipe component P3 shown in FIG. It is possible to eliminate the thinning part.

  Furthermore, when the cylindrical body P as a material is a welded pipe, when the cylindrical body P is set in the mold 4, the welded pipe is connected to the center point of the cross section of the deformed portion P32 of the expanded diameter pipe part P3. It is preferable to install the welded portion so as to be located in a circumferential direction portion closest to the position because it is possible to suppress breakage during the diameter expansion process.

  Existing means can be used for the pressing mechanism of the mold and punch, and examples thereof include a hydraulic cylinder, a gas cylinder, a pressing mechanism such as a spring and rubber.

  According to the manufacturing apparatus of the present invention, the tubular material is set in a predetermined mold, and the squeezing process is performed after the squeezing process with a predetermined diameter-enlarging punch. Since replacement is not necessary, the process and cost can be reduced. Furthermore, since it is possible to prevent the material and the axis of the diameter expansion punch from deviating, the dimensional accuracy of the diameter expansion pipe part P3 is stabilized and the product yield is also improved.

  In the above description, the embodiment including the concentric tube expanding punch 1 (1-1, 1-2), the eccentric tube expanding punch 2, the diameter reducing punch 3, and the mold 4 has been described as an example. Depending on the shape of P3), in addition to the concentric tube expansion punch 1 (1-1, 1-2), a concentric tube expansion punch having another outer diameter may be added as appropriate.

3. Manufacturing method according to the present invention The manufacturing method according to the present invention includes a concentric tube expanding process, an eccentric tube expanding process, and a diameter reducing process.

(3-1) Concentric tube expanding step As shown in FIG. 2A, in the concentric tube expanding step, the concentric tube expanding punch 1 is pushed in from the end of the tube P on the tube expansion hole side in the axial direction of the tube P. The first intermediate molded product P1 is manufactured by performing concentric tube expansion processing on the cylindrical body P.

  By providing a concentric tube expanding step for uniformly expanding the tubular body P in the circumferential direction of the cross section in the previous stage of the eccentric tube expanding step for forming the desired changed portion P32 into a shape, the shape of the changing portion P32 is different in the circumferential direction of the cross section. Even if it exists, since the thinning of the thickness in the cross section circumferential direction of the change part P32 can be suppressed, it is preferable.

  That is, when the eccentric tube is expanded from the initial step, it is possible to prevent only the side where the tube is expanded from being extremely thinned, and in the conventional method, the material easily flows in the direction of the tube axis, so the end face of the product is straight. In the present invention, it is possible to suppress the phenomenon of slanting rather than to reduce the product yield.

  In the concentric tube expansion step, it is preferable to perform concentric tube expansion processing on the cylindrical body P by using the concentric tube expansion punch 1 having an outer diameter larger than the inner diameter of the cylindrical body P which is a raw tube and smaller than the inner diameter of the changing portion P32. .

  In addition, an inclined portion 11 having an inclination angle β (hereinafter referred to as “punch half angle β”) larger than a predetermined inclination angle α in a change portion P32 of a desired expanded pipe part manufactured in the present invention is press-fitted into a cylinder. It is preferable to use a concentric tube expansion punch at the side tip. Here, the inclination angle α indicates an average value of the inclination angles in the circumferential direction of the cross section of the changing portion P32.

  The pushing amount of the metal material in the concentric tube expansion process can be adjusted as appropriate by adjusting the punch half angle β with respect to the magnitude of the inclination angle α and the length of the changing portion P32. If the metal material becomes insufficiently pressed, cracks are likely to occur in the change part, and if the amount of pressing increases, the load due to the pressing of the punch is too large and buckling tends to occur. Since the curling deformation occurs such that the end portion on the side is wound outward, the punch half angle β is preferably larger than the inclination angle α and in the range of 30 ° to 60 °.

  The tube expansion rate in one concentric tube expansion step is preferably 25% or less, and more preferably in the range of 20 to 25%.

  Although not particularly limited, the cylindrical body P is preferably disposed inside the mold 4 during the concentric tube expansion process.

(3-2) Eccentric Tube Expansion Step As shown in FIG. 2D, in the eccentric tube expansion step, the eccentric tube expansion punch 2 having an outer surface shape that matches the inner surface shape of the changing portion P32 and the outer surface shape of the changing portion P32 are matched. A mold 4 having an inner surface shape is used.

  The eccentric tube expansion punch 2 is pushed in the axial direction of the portion where the concentric tube expansion processing is performed in the first intermediate molded product P1 installed in the mold 4 to perform the eccentric tube expansion processing on the first intermediate molded product P1. Thus, the second intermediate molded product P2 having the shape of the changing portion P32 and having the end portion expanded more than the diameter-expanded tube component P3 that is the final product is manufactured.

  Moreover, as shown in FIG.2 (b), not only the inner surface shape of the change part P32 but the metal mold | die 4 which has the outer surface shape which agree | coincides with the one part inner surface shape of the enlarged diameter part P33, and the eccentric tube expansion punch 2 are used. Eccentric tube expansion may be performed. In that case, in the eccentric tube expansion process, a part of the diameter expansion part P33 of the desired diameter expansion pipe part P3 is formed at the same time. Therefore, in the subsequent diameter reduction process, the diameter expansion part P33 that was not formed in the eccentric tube expansion process. The diameter reducing process may be performed on the shape portion.

  Furthermore, when the die 4 and the eccentric tube expansion punch 2 to be used are divided into a plurality of parts, the pushing of each eccentric tube expansion punch may be divided into several stages.

(3-3) Diameter reduction processing step As shown in FIG. 2 (e), in the diameter reduction processing step, the diameter reduction punch 3 having an inner surface shape that matches the outer surface shape of the enlarged diameter portion P33 is formed by the second intermediate molding. The outer diameter of the end of the product P2 is pushed to reduce the diameter of the end of the second intermediate molded product P2.

  The diameter-reducing punch 2 is preferably subjected to diameter-reducing processing by being pushed in from the outside of the end portion of the second intermediate molded product P2 in the axial direction of the second intermediate molded product P2. In this way, by pressing the reduced diameter punch from the axial direction, it is possible to reduce the diameter without significantly moving the mold 4, which is preferable. Further, even when the mold 4 is moved, it is only necessary to design the mold 4 to move outward from the second intermediate molded product P2 only at a part of the portion where the reduced diameter punch 3 is pushed. It can be manufactured by a simple process.

  Moreover, the manufacturing method of this invention may further include the cutting process which cut | disconnects the thinning part formed in the front-end | tip of the enlarged diameter part P33 of the enlarged diameter pipe component P3. For example, although the thinned portion is shown at the tip of the enlarged diameter pipe part shown in FIG. 4, it can be cut along the dotted line to cut out the reduced thickness part of the enlarged diameter pipe part.

  Furthermore, when the cylinder P used as a raw material is a welded pipe, when the cylinder P is set in the mold 4, the welded pipe is used in the deformed portion P32 of the enlarged-diameter pipe part P3 having a desired shape. It is preferable to install the welded portion so as to be located in the circumferential direction portion closest to the position serving as the center point of the cross section, because breakage during diameter expansion processing can be suppressed.

  Existing means can be used for pressing the mold and punch, and examples thereof include a hydraulic cylinder, a gas cylinder, a pressurizing mechanism such as a spring and rubber.

  According to the manufacturing method of the present invention, it is possible to set a tubular material in a predetermined mold and perform mouth drawing after a widening process with a predetermined diameter expanding punch, so there is no need to use a plurality of molds. Since there is no need to change the material, the process and cost can be reduced. Furthermore, since it is possible to prevent the material and the axis of the expanded punch from being displaced, the product dimensions and shape are stabilized, and the product yield is improved.

  The above has described a manufacturing method comprising one concentric tube expanding step, an eccentric tube expanding step, and a diameter reducing processing step. However, depending on the shape of the diameter expanding tube component, a further concentric tube expanding step using a concentric tube expanding punch having a different outer diameter May be added.

  Below, the manufacturing method of the aspect provided with three of a 1st concentric tube expansion process, a 2nd concentric tube expansion process, and a 3rd concentric tube expansion process is demonstrated as a concentric tube expansion process.

(4-1) First Concentric Tube Expansion Step As shown in FIG. 2A, in the first tube expansion step, the inclination angle α of the change portion P32 of the desired diameter expansion tube component P3 manufactured in the present invention. Also, the first concentric tube expanding punch 1a having a larger punch half angle β1 and an outer diameter d1 larger than the inner diameter of the cylinder P and smaller than the inner diameter of the changing portion P32 is used. By pushing the first concentric tube expansion punch 1a in the axial direction of the cylinder body P from the end side of the cylinder body P, the cylinder body P is expanded, and the 1a intermediate molded product P1a is manufactured.

  The tube expansion rate of the tube expansion process in the first tube expansion step is preferably 25% or less, and more preferably in the range of 20 to 25%.

(4-2) Second Concentric Tube Expansion Step As shown in FIG. 2 (b), in the second tube expansion step, a predetermined inclination angle α in the change portion P32 of the desired diameter expansion tube component manufactured in the present invention. The second concentric tube expanding punch 1b is used which has a larger punch half angle β2 and an outer diameter d2 which is larger than the inner diameter of the cylinder P and smaller than the inner diameter of the changing portion P32. From the end of the 1a intermediate molded product P1a on the tube expansion hole side to the axial direction of the 1a intermediate molded product P1a, the second is from the first concentric tube expansion step to the position before the first concentric tube expansion punch is pushed. By pushing the tube expansion punch 1b, the 1a intermediate molded product P1a is expanded to produce the 1b intermediate molded product P1b.

  The tube expansion rate in the second concentric tube expansion step is preferably 25% or less, and more preferably in the range of 20 to 25%.

(4-3) Third Concentric Tube Expansion Step As shown in FIG. 2 (c), in the third tube expansion step, a predetermined inclination angle α at the change portion P32 of the desired diameter expansion tube component manufactured in the present invention. A third concentric tube expansion punch 1c having a larger punch half angle β3 and an outer diameter d3 larger than the inner diameter of the cylinder P and smaller than the inner diameter of the changing portion P32 is used. From the end of the first-b intermediate molded product P1b on the tube expansion hole side to the axial direction of the first-b intermediate molded product P1b, the third concentric tube-expanding step is performed until the second concentric tube-expanding punch is pushed into the position. By pushing the tube expansion punch 1c, the 1b intermediate molded product P1b is expanded to produce the 1c intermediate molded product P1c.

  The tube expansion rate of the tube expansion process in the third concentric tube expansion step is preferably 25% or less, and more preferably in the range of 20 to 25%.

  The eccentric tube expanding process and the diameter reducing process are as described above.

  It is preferable to perform a plurality of concentric tube expanding steps as described above, because the thickness reduction rate in the changed portion P32 and the expanded portion P33 of the expanded tube component formed into a desired shape can be reduced.

4). Metal material used in the present invention The present invention is, for example,
(A) The ratio (t ₀ / D) is in the range of 0.005 to 0.3, and t ₀ = 0, where t ₀ is the average thickness of the raw steel pipe before opening and D is the outer diameter. In the range of 5-30 mm, D = 15-700 mm,
(B) The thickness reduction rate when the thickness of the material steel pipe before squeezing and forming is t ₀ and the thickness after squeezing and forming at the end in the axial direction of the end squeezed steel pipe is t ₁ “{(t ₀₋ t ₁ ) / t ₀ } × 100 (%) ”is 0 to 40,
(C) The length L (mm) of the diameter-expanded portion formed by flaring the end of the steel pipe toward the axial end of the steel pipe is in the range of 0D to 10D.
(D) Work hardening coefficient (distortion effect index) n value of the end-opened steel pipe is in the range of 0.005 to 0.4,
(E) The r value, which is a characteristic value representing the deep drawability of the end-opened steel pipe, can be applied in the range of 0.3 to 4.0. In particular, in the squeeze molding, if the n value is too small, the molding load becomes large and it is easy to buckle. On the other hand, if the r value is too small, the material is difficult to flow in. descend).

  The steel type of the material steel pipe is not particularly limited in the present invention.

  Although the metal material used for this invention is not specifically limited, Even if it is a metal material with high intensity | strength like stainless steel and high-tensile steel, it can use preferably.

  Moreover, even if the raw material has a tensile strength of 590 MPa or more, it can be preferably used.

  According to the present invention, it is possible to manufacture a diameter-expanded pipe component without buckling or cracking even with such a high strength material.

  Furthermore, the present invention can be preferably used even if the material is a welded pipe.

  According to the present invention, even if the material is a welded pipe, extreme thinning and breakage can be suppressed in the vicinity of the welded portion and on the opposite side of the welded portion in the circumferential direction of the material. Diameter pipe parts can be manufactured.

  The diameter-expanded pipe part manufactured according to the present invention can be preferably used as a catalyst case for an automobile or a motorcycle, an oil supply pipe for injecting automobile fuel, and the like.

1, 1-1, 1-2: Concentric tube expansion punch 2: Eccentric tube expansion punch 3: Reduced diameter punch 4: Mold

Claims (14)

The cylindrical body, which is a metal material, is processed to form a general part having a predetermined diameter and a tip formed at the tip of the cylindrical body and expanded to a predetermined size with respect to the general part. An enlarged diameter portion having an axial direction decentered at a predetermined crossing angle with respect to the axial direction of the portion, and formed between the general portion and the enlarged diameter portion and from the general portion toward the enlarged diameter portion A method of manufacturing a diameter-expanded pipe part having a change part that expands to a predetermined inclination angle in an axial direction,
At least one concentric tube expansion step for producing a first intermediate molded product by pushing a concentric tube expansion punch in the axial direction of the tube body and performing concentric tube expansion on the tube body;
The concentric tube expansion process in the first intermediate molded product in which an eccentric tube expansion punch having an outer surface shape that matches the inner surface shape of the change portion is installed in a mold having an inner surface shape that matches the outer surface shape of the change portion. By pushing in the axial direction of the portion that has been performed and performing eccentric tube expansion processing on the first intermediate molded product, the end portion is expanded than the expanded tube component that has the shape of the changed portion and is the final product. An eccentric tube expansion process for manufacturing the second intermediate molded product,
A diameter-reducing punch having an inner surface shape that matches the outer surface shape of the enlarged-diameter portion is pushed into the outer side of the end portion of the second intermediate molded product to reduce the diameter of the end portion of the second intermediate molded product. And a diameter-reducing processing step for performing a diameter expansion pipe component manufacturing method.   The diameter-reducing punch is subjected to diameter-reducing processing by being pushed from the outside of the end portion of the second intermediate molded product in the axial direction of the second intermediate molded product. Manufacturing method for expanded diameter pipe parts.   In the concentric tube expanding step, a concentric tube expanding punch having a punch half angle larger than the inclination angle of the changing portion, an outer diameter larger than an inner diameter of the cylindrical body, and smaller than an inner diameter of the changing portion is formed on the cylindrical body. The method for manufacturing a diameter-expanded pipe component according to claim 1 or 2, wherein the cylindrical body is concentrically expanded by being pushed in an axial direction at a tube expansion rate of 25% or less.   The method for manufacturing a diameter-expanded pipe component according to any one of claims 1 to 3, further comprising a step of cutting a thinned portion formed at a tip of the diameter-expanded portion.   The method for manufacturing a diameter-expanded pipe component according to any one of claims 1 to 4, wherein the cylindrical body is a welded pipe.   The said raw material has the tensile strength of 590 Mpa or more, The manufacturing method of the diameter expansion pipe components described in any one of Claim 1-5 characterized by the above-mentioned.   The method for manufacturing a diameter-expanded pipe part according to any one of claims 1 to 6, wherein the diameter-expanded pipe part is an engine exhaust system muffler or a catalyst case of an automobile or a motorcycle. The cylindrical body, which is a metal material, is processed to form a general part having a predetermined diameter and a tip formed at the tip of the cylindrical body and expanded to a predetermined size with respect to the general part. An enlarged diameter portion having an axial direction decentered at a predetermined crossing angle with respect to the axial direction of the portion, and formed between the general portion and the enlarged diameter portion and from the general portion toward the enlarged diameter portion An apparatus for manufacturing a diameter-expanded pipe component having a change part that expands to a predetermined inclination angle in an axial direction,
At least one concentric tube expansion punch for producing a first intermediate molded product by being pushed in the axial direction of the tube body and performing concentric tube expansion processing on the tube body;
A mold having an inner surface shape that matches the outer surface shape of the change portion;
It has an outer surface shape that matches the inner surface shape of the changing portion, and is pushed in the axial direction of the portion where the concentric tube expansion processing is performed in the first intermediate molded product installed in the mold, An eccentric tube expansion punch for producing a second intermediate molded product having a shape of the change portion and having an end portion expanded from the diameter-expanded tube component as a final product by performing an eccentric tube expansion process on the intermediate molded product; ,
It has an inner surface shape that matches the outer surface shape of the diameter-enlarged portion, and is pressed to the outside of the end portion of the second intermediate molded product to reduce the diameter of the end portion of the second intermediate molded product. An apparatus for manufacturing a diameter-expanded pipe part, comprising:   The diameter-reducing pipe component manufacturing apparatus according to claim 8, wherein the reduced diameter punch is pushed in from the outside of the second intermediate molded product in the axial direction of the second intermediate molded product.   The concentric tube expansion punch has a punch half angle larger than the inclination angle of the changing portion, an outer diameter larger than the inner diameter of the cylindrical body, and smaller than an inner diameter of the changing portion, and is arranged in the axial direction of the cylindrical body. 10. The apparatus for manufacturing a diameter-expanded pipe component according to claim 8, wherein the cylindrical body is expanded by being pushed in at a tube expansion rate of 25% or less.   The apparatus for manufacturing a diameter-expanded pipe component according to any one of claims 8 to 10, further comprising a cutting means for cutting a thinned portion formed at a tip of the diameter-expanded portion. .   The said raw material is a welded pipe, The manufacturing apparatus of the enlarged diameter pipe component described in any one of Claim 8-11 characterized by the above-mentioned.   The apparatus for manufacturing a diameter-expanded pipe component according to any one of claims 8 to 12, wherein the material has a tensile strength of 590 MPa or more.   14. The apparatus for producing a diameter-expanded pipe part according to claim 7, wherein the diameter-expanded pipe part is an engine exhaust system muffler or a catalyst case of an automobile or a motorcycle.