Method and apparatus for manufacturing elbow product

Abstract

To provide a method and apparatus capable of easily and advantageously manufacturing a desired elbow product while reducing processing steps and improving processing quality.SOLUTION: A straight tubular pipe material 2 of a predetermined length is prepared, and press working is applied to the pipe material 2 to form a first annular bulging part 4a and a second annular bulging part 4b respectively at end portions on both sides in the axial direction of the pipe material 2, thereby obtaining an end-processed product 6. Then, the portion of the end-processed product 6 where the first annular bulging part 4a is formed is subjected to bending so as to form a bent pipe part 8 curved at a predetermined angle, thereby obtaining a bent product 10. Subsequently, a third annular bulging part 4c is formed in a straight pipe portion between the bent pipe part 8 and the second annular bulging part 4b of the bent product 10, thereby manufacturing a desired elbow product 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for manufacturing an elbow product, and more particularly to a method and apparatus for advantageously manufacturing a desired elbow product. [Background technology]

[0002] Metal elbow products having a bent pipe section bent at a predetermined angle have been widely used as coupling members in various machines and devices. Specifically, elbow products are used in a form in which one end is fixedly attached to the main body of a heat exchanger such as a motor oil cooler for a hybrid vehicle, an EGR cooler, a rectangular engine oil cooler, or a warmer & cooler. In this case, a hose for circulating a liquid such as a coolant is connected to the other end of the elbow product, and the outer periphery of the hose is fastened with a fastening band.

[0003] One such elbow product has been revealed to have a structure in which an annular bulge, which is a ring-shaped bead portion of a predetermined height, is provided at each end of the axial direction of a metal pipe body, and further, such an annular bulge is provided at an intermediate portion of the pipe body in the axial direction, and a curved pipe portion bent at a predetermined angle is provided between the intermediate annular bulge and the annular bulge at one end.

[0004] Such elbow products have conventionally been manufactured by forming annular bulges at both ends and the middle of a straight pipe material, and then bending the straight pipe section between the annular bulge at one end and the middle annular bulge to form a curved pipe section, as shown in Japanese Patent Publication No. 7233099. More specifically, as shown in Fig. 9, a straight pipe material 102 made of a predetermined metal material is first clamped in a predetermined forming die and subjected to a first press process in which the pipe material is pressed axially, thereby forming a pipe wall portion of the pipe material 102 by bulging radially outward within the annular bulge forming section of the forming die, thereby forming one annular bulge 104a at one end of the pipe material 102. Next, a second press process is performed to further press the end of the pipe material 102, causing the pipe wall portion of the pipe material 102 to bulge radially outward in the annular bulge portion forming portions of the forming mold positioned at the other end side and the intermediate portion of the pipe material 102, thereby forming two annular bulges 104b, 104c at the other end side and the intermediate portion of the pipe material 102, thereby producing a pressed member 106 having the desired three annular bulges 104a, 104b, 104c. Then, the pressed member 106 is further bent to bend the straight pipe portion between the annular bulge portion 104a at one end side and the annular bulge portion 104c at the intermediate portion at a predetermined angle to form a curved pipe portion 108, thereby producing the desired elbow product 110.

[0005] However, in the elbow product 110 manufactured in this manner, the pipe material 102 undergoes work hardening during the second press process to form the annular bulges 104c and 104b at the middle and other end portions of the pipe material 102, respectively. This means that when the bending process to form the curved pipe portion 108 is subsequently performed, there is a risk of the pipe cracking, and deformation may occur at the middle annular bulge 104c, which creates significant problems in terms of product quality and yield.

[0006] Furthermore, Japanese Patent No. 6963981 discloses another method for manufacturing an elbow product having three annular bulges formed at both ends and the middle of a pipe body, and a curved pipe portion formed between two of the annular bulges and curved at a predetermined angle. That is, in this method, a straight pipe material of a predetermined length is cut out from a long, straight pipe material, and then one end of the straight pipe material is pressed to form a ring-shaped bead portion (annular bulge portion) of a predetermined height, thereby obtaining an end-processed material. The end-processed material is then bent to form an elbow material having a curved pipe portion bent at a predetermined angle and a straight pipe portion extending linearly from the end. The straight pipe portion of the elbow material is then subjected to end processing and shearing using a roller processing member to form two annular bulges and cut off the excess length of the straight pipe portion, thereby producing the desired elbow product. However, even with this manufacturing method, the following problems are inherent.

[0007] In other words, in the processing of elbow blanks using such roller processing members, the shearing process to cut off the end of the straight tubular portion of the elbow blank and determine its length involves shearing, separating, and removing the end portion of the straight tubular portion of the elbow blank that protrudes from the housing portion of the mold using a rotary shearing blade on the roller processing member and a fixed shearing blade on the outer opening of the housing portion of the mold. Therefore, burrs inevitably form at the sheared portion of the straight tubular portion, necessitating a burr removal process after the shearing process, which increases the number of processes and ultimately leads to higher manufacturing costs. Furthermore, during the molding of the annular bulge, material tends to seep into the mating surfaces of the mold, which can easily result in burr-like protrusions or projections on the annular bulge. In addition, there are some inherent problems with the shape precision of the annular bulge. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 7233099 [Patent Document 2] Patent No. 6963981 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in light of the above circumstances, and its object is to provide a method and apparatus for easily and advantageously manufacturing the desired elbow product while reducing the number of processing steps and improving the processing quality. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the present invention can be suitably implemented in various aspects as listed below, and the aspects described below can be adopted in any combination. It should be understood that the aspects and technical features of the present invention are not limited to those described below, but can be recognized based on the description of the entire specification and the inventive idea disclosed in the drawings.

[0011] In order to solve the above-mentioned problems, the present invention provides a method for manufacturing an elbow product having a first annular bulge located at one end of a pipe in the axial direction, bulging outward in the radial direction and extending continuously in the circumferential direction, a second annular bulge located at the other end of the pipe in the axial direction, bulging outward in the radial direction and extending continuously in the circumferential direction, a third annular bulge located at an intermediate portion of the pipe in the axial direction, bulging outward in the radial direction and extending continuously in the circumferential direction, and a curved pipe portion formed between the third annular bulge and the first annular bulge and curved at a predetermined angle, the method comprising: (a) selecting a predetermined temperature for providing the elbow product; The gist of the method for manufacturing an elbow product is that it includes the steps of: (a) preparing a straight pipe material of a given length; (b) press-forming the pipe material to form the first and second annular bulges at the end portions on both axial sides of the pipe material to obtain an end product; (c) bending the end product at the side where the first annular bulge is formed to obtain a bent product having the curved pipe portion bent at a predetermined angle; and (d) forming the third annular bulge in the straight pipe portion of the bent product between the curved pipe portion and the second annular bulge.

[0012] In one preferred embodiment of the method for manufacturing an elbow product according to the present invention, the press working of the pipe material is carried out by pressing the pipe material in the axial direction to bulge the pipe wall portion radially outward, and the first and second annular bulges are formed at the end portions on both axial sides of the pipe material, respectively.

[0013] In another preferred embodiment of the method for manufacturing an elbow product according to the present invention, one end portion of the end processed product including the first annular bulge portion is fixed and held, while the other end portion of the end processed product including the second annular bulge portion is restrained. In this state, the bending portion located between the first annular bulge portion and the second annular bulge portion of the end processed product is bent and deformed, and as the bending deformation progresses, the end processed product is pushed axially toward the bending portion, thereby bending the end processed product.

[0014] Furthermore, according to another preferred embodiment of the method for manufacturing an elbow product according to the present invention, a bending form is used which has a semicircular bending portion, a pivot shaft provided at the center of the semicircular shape of the bending portion, and a bending groove of semicircular cross section provided along the outer periphery of the bending portion, and by rotating the bending form about the pivot shaft, the bending portion of the end processed product introduced into the bending groove is bent and deformed, while a wiper member having a receiving surface corresponding to the outer periphery of the inner bend portion of the bending portion is inserted between the bending groove and the inner bend portion of the bending portion, and the receiving surface of the wiper member is brought into contact with and held in place by the inner bend portion of the bending portion, thereby preventing the formation of wrinkles in the inner bend portion.

[0015] In addition, according to yet another preferred embodiment of the method for manufacturing an elbow product according to the present invention, the third annular bulge is formed by rotating a roller processing member inserted and positioned inside the pipe of the bent product and pressing the inner surface of the pipe, thereby bulging the pipe wall radially outward.

[0016] In the present invention, the elbow product is preferably a coupling part to which a hose for circulating a predetermined fluid is connected, and the hose connection part of the coupling part is constituted by a straight pipe section between the curved pipe section and the second annular bulge section.

[0017] The present invention also provides an apparatus for manufacturing an elbow product having a first annular bulge located at one axial end of a pipe body, bulging outward in the radial direction and extending continuously in the circumferential direction, a second annular bulge located at the other axial end of the pipe body, bulging outward in the radial direction and extending continuously in the circumferential direction, a third annular bulge located at an intermediate portion of the pipe body in the axial direction, bulging outward in the radial direction and extending continuously in the circumferential direction, and a curved pipe portion formed between the third annular bulge and the first annular bulge and bent at a predetermined angle, comprising: (i) a straight pipe of a predetermined length; The gist of the invention is also an elbow product manufacturing device comprising: (i) a press processing device that presses a material to form the first and second annular bulges at both axial end portions of the pipe material to produce an end product; (ii) a bending device that bends the end product at the side where the first annular bulge is formed to produce a bent product having the curved pipe portion bent at a predetermined angle; and (iii) a bulge forming device that forms the third annular bulge at the straight pipe portion of the bent product between the curved pipe portion and the second annular bulge.

[0018] In one preferred embodiment of the manufacturing apparatus for an elbow product according to the present invention, the bending device has a semicircular bending portion, a rotation axis provided at the center of the semicircular shape of the bending portion, and a bending groove having a semicircular cross section provided along the outer circumferential surface of the bending portion, and a bending form that is introduced into the bending groove and that bends a bending portion located between the first annular bulge portion and the second annular bulge portion of the end processed product by rotating it about the rotation axis, and a bending form that is superimposed on the bending form to bend the bending portion. The end processing device is characterized by having a clamping member that is rotated together with the bending form while clamping and fixing one end side portion of the end processing product including the first annular bulge portion between the bending form and the other end side portion of the end processing product including the second annular bulge portion, and a pressure member that receives the other end side portion of the end processing product including the second annular bulge portion from the bending processing portion of the end processing product, abuts against the end face of the other end side portion, and while restricting its axial movement, presses the end processing product axially toward the bending processing portion as the bending of the end processing product progresses.

[0019] Furthermore, according to another preferred embodiment of the manufacturing apparatus for an elbow product according to the present invention, a restraining member is further provided which abuts against and restrains the end surface of one end side portion of the end processed product, including the first annular bulge portion, which is clamped between the bending form and the clamp member, thereby preventing axial movement of the end processed product.

[0020] Furthermore, according to another preferred embodiment of the manufacturing apparatus for elbow products according to the present invention, the apparatus has a receiving surface that corresponds to the outer peripheral surface of the inner bend portion of the bent portion of the end processed product, which is accommodated in the bending groove provided in the bending processing section of the bending form, and the receiving surface abuts against and supports the inner bend portion, thereby preventing the occurrence of wrinkles in the inner bend portion, and is characterized by being arranged so as to enter between the end processed product and the bending groove of the bending form. [Effects of the Invention]

[0021] Thus, in accordance with the manufacturing method and apparatus for elbow products of the present invention, annular bulges are formed on both axial end portions of a straight pipe material of a predetermined length that will produce the desired elbow product, and then the material is bent to form a curved pipe portion. Thereafter, an intermediate annular bulge is formed in the straight pipe portion between the curved pipe portion and the annular bulge at one end. Therefore, unlike conventional methods, pipe cracking due to work hardening that accompanies the processing of the annular bulge can be effectively suppressed or avoided, and deformation of the annular bulge can also be advantageously suppressed or eliminated.

[0022] Furthermore, in accordance with the method and apparatus for manufacturing elbow products of the present invention, the end of the bent product having the curved pipe portion formed thereon is not sheared off at the same time as the annular bulge is formed, so there is no need to perform a further deburring process after such processing. This makes it possible to advantageously manufacture the desired elbow products while improving the product shape, thereby effectively shortening the process, thereby advantageously improving productivity and reducing product costs, and making it possible to obtain the desired elbow products in an industrially advantageous manner. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is an explanatory diagram showing, in side view, each component used or manufactured in the manufacturing process of an elbow product according to the present invention, where (a) shows a straight pipe material of a predetermined length prepared to manufacture the desired elbow product, (b) shows an end processed product obtained by pressing the pipe material and forming an annular bulge portion on each end portion on both axial sides, (c) shows a bent product obtained by bending the end processed product to form a curved pipe portion, and (d) shows an elbow product obtained by forming an annular bulge portion in the straight pipe portion in the middle of such a bent product. [Figure 2] FIG. 1 is an explanatory view showing an example of the end faces of a punch and a half die for forming an end processed product by press working according to the present invention. [Figure 3] 3 is an explanatory diagram showing the process of forming an end processed product by press processing using the punch and mold shown in FIG. 2 according to the present invention, where (a) shows the state in which the pipe material is set in the mold, (b) shows the state in which an annular bulge is formed between the punch and the sub-clamp by pressing with the punch, and (c) shows the state in which an annular bulge is formed between the sub-clamp and the clamp body by pressing with the punch. [Figure 4] 4A and 4B are enlarged cross-sectional explanatory views showing the annular bulge formed at one end portion in the process of forming the end processed product shown in FIG. 3, in which FIG. 4A is an enlarged explanatory view of the annular bulge formed between the punch and the sub-clamp, and FIG. 4B is an enlarged explanatory view of the annular bulge formed at the other end portion in the process of forming the end processed product shown in FIG. [Figure 5] 1 is an exploded explanatory view showing an example of an apparatus capable of bending an end processed product according to the present invention. [Figure 6] 6A, 6B, and 6C are explanatory views of a wiper member used in the bending apparatus shown in FIG. 5, in which (a), (b), and (c) are a front view, a bottom view, and a left side view thereof, respectively, and (d) is a perspective schematic view thereof. [Figure 7] 6 is an explanatory diagram showing an example of a bending process for an end processed product using the bending device shown in FIG. 5, where (a) shows the state before the start of bending, (b) shows the state during bending, and (c) shows the state after bending. [Figure 8] 10A to 10C are explanatory views showing an example of a process for forming an annular bulge portion in the middle portion of a bent product according to the present invention. [Figure 9] FIG. 1 is a process diagram illustrating an example of a conventional method for manufacturing an elbow product using a straight pipe material. DETAILED DESCRIPTION OF THE INVENTION

[0024] In order to more specifically clarify the configuration of the manufacturing method and manufacturing apparatus for elbow products according to the present invention, a detailed description will be given below based on a representative embodiment of the present invention with reference to the drawings.

[0025] First, FIG. 1 shows an example of a pipe material prepared in the manufacturing method of an elbow product according to the present invention, the end processed products and bent products obtained in each processing step, and the final elbow product.

[0026] To manufacture a metal elbow product made of aluminum, copper, or other materials, a straight metal pipe material, such as a long aluminum pipe or copper pipe, is first prepared, and then a pipe blank 2, as shown in Figure 1(a), is cut out from the straight metal pipe material using a conventional cutting device to the length required to produce the final elbow product.

[0027] The prepared pipe blank 2 is then pressed to form an end product 6, as shown in Fig. 1(b), in which annular bulges 4a, 4b are formed at both axial end portions. Conventional end processing, such as beading, bulging, or spooling, is used for the press processing of such pipe blanks, so that a first annular bulge 4a is formed at one end of the pipe blank 2 with a predetermined height, and a second annular bulge 4b ​​is formed at the other end with a predetermined height.

[0028] Next, the end processed product 6 thus obtained is bent at the side where the first annular bulge 4a, which is one of the annular bulges, is formed, thereby forming a bent product 10 having a curved pipe section 8 bent at a predetermined angle as shown in Figure 1(c).Furthermore, a third annular bulge 4c is formed as an annular bulge located in the axial middle of the pipe body in the straight pipe section between the curved pipe section 8 and the second annular bulge 4b, which is the other annular bulge, thereby forming the desired elbow product 12 in the form shown in Figure 1(d).

[0029] The end processed product 6 having the annular bulges 4a, 4b at both ends as described above can be easily formed, for example, using a press machine including a mold 14 and a punch 16, as shown in FIG. 2. The mold 14 is divided into two halves, an upper mold and a lower mold, and FIG. 2 shows the split surface (top surface) of the lower mold 14L. The lower mold 14L is composed of a clamp body 17L and a sub-clamp 18L axially slidably held within the clamp body 17L. The clamp body 17L has a holding hole 20L for receiving and holding the end of the pipe material 2, while the sub-clamp 18L has a clamp hole 22L extending therethrough. The clamp hole 22L has an annular bulge-forming recess 24L with a larger diameter than the clamp hole 22L at the end opposite the holding hole 20L.

[0030] In addition, the other half of the upper mold (14U), which is superimposed on the lower mold 14L to form the mold 14, has a structure or shape similar to that of the lower mold 14L.For this reason, the mold components of the lower mold 14L are each indicated with an "L" after the number, and the overall shape of each mold component should be understood when it is combined with the parts of the upper mold (14U) which have a similar structure or shape.

[0031] The punch 16 combined with the die 14 having such a configuration is disposed opposite the sub-clamps (18L, 18U) of the die 14, and is adapted to abut against the protruding end faces of the pipe blank 2 to apply a pressing force in the axial direction thereof, and also to abut against the end faces of the sub-clamps (18L, 18U) to press the pipe blank 2 into the clamp bodies (17L, 17U). For this purpose, a tapered hole 26 having an outwardly tapered inner wall surface and a depth shallower than the length of the pipe blank 2 protruding from the sub-clamps (18L, 18U) is provided in the surface of the punch 16 facing the sub-clamps (18L, 18U). This core 28 penetrates into the inside of the end of the pipe material 2 housed in the tapered hole 26, and enables the end of the pipe material 2 to be effectively bulged outward by pressing with the punch 16.

[0032] When the press working device comprising the die 14 and punch 16 thus configured is used to form the annular bulges 4a, 4b at both ends of the pipe blank 2 to produce the end processed product 6, for example, as shown in Figure 3(a), first, one end of the pipe blank 2 is in a state where it protrudes from the clamp holes (22L, 22U) of the sub-clamps (18L, 18U) by a length sufficient to form the annular bulges 4a, 4b at both ends, and then the upper die (14U) is placed over the lower die 14L to clamp and fix the pipe blank 2 in the clamp holes (22L, 22U). At this time, the other end of the pipe blank 2 is accommodated and held in the holding holes (20L, 20U) provided in the clamp bodies (17L, 17U).

[0033] Next, as shown in Figure 3(b), the punch 16 is moved relatively closer to the sub-clamps (18L, 18U) of the die 14, so that the protruding end of the pipe blank 2 is accommodated in its tapered hole 26 and the core 28 is inserted into the protruding end. As the punch 16 further moves relatively closer to the sub-clamps (18L, 18U), it presses or pushes the pipe blank 2 in the axial direction, causing the end of the pipe blank 2 to bulge outward in the radial direction at the pushing-in end in accordance with the shape of the tapered hole 26 of the punch 16. As a result, a (second) annular bulge 4b ​​on one end side is formed in a bulge shape, as shown enlarged in Figure 4(a), to form a one-side end processed product 5.

[0034] Thereafter, with the punch 16 in contact with the end faces of the sub-clamps (18L, 18U), the punch 16 is further pressed in the relative direction, moving the sub-clamps (18L, 18U) axially and forcing them into the clamp bodies (17L, 17U). As a result, as shown in Figure 3(c), the pipe wall portion on the other end side of the pipe blank 2 is deformed radially outward and bulged into the bulge-forming recesses (24L, 24U) provided on the ends of the sub-clamps (18L, 18U). As a result, the desired annular bulge (first) 4a on the other end side is formed, as shown in Figure 4(b), to obtain the end product 6. The end product 6 thus formed is then removed by opening the lower die 14L and the upper die 14U and is then subjected to the next bending process.

[0035] Furthermore, when bending the intermediate portion in the axial direction of the end processed product 6 thus obtained, specifically the straight pipe portion biased toward one of the annular bulges 4a of the two end portions, i.e., the bending portion, to form the curved pipe portion 8 curved at a predetermined angle to obtain the desired bent product 10, it is advantageous to fix and hold one end portion including one annular bulge 4a in the end processed product 6, while fixing and holding the other annular bulge 4a in the end processed product 6. In this method, the bending process of the end processed product 6 is carried out by bending and deforming the bending process portion located between one annular bulge portion 4a and the other annular bulge portion 4b in the end processed product 6 while restraining the other end side portion including the portion 4b, and as this bending deformation progresses, pushing the end processed product 6 axially toward the bending process portion, thereby advantageously eliminating or reducing problems such as sink marks at the end of the end processed product 6 due to the bending process.

[0036] Furthermore, when performing the bending process as described above, a bending form having a semicircular bending portion, a rotation axis located at the center of the semicircular shape of the bending portion, and a bending groove with a semicircular cross-section located along the outer peripheral surface of the bending portion is used, and by rotating this bending form around the rotation axis, the bending portion of the end processed product 6 introduced into the bending groove is bent and deformed, while a wiper member having a receiving surface corresponding to the outer peripheral surface shape of the inner bend portion of the bending portion is inserted between the bending groove and the inner bend portion of the bending portion, and the receiving surface of the wiper member is abutted against and held against the inner bend portion of the bending portion, thereby avoiding or preventing the occurrence of wrinkles in the inner bend portion.

[0037] To carry out the above-described bending method, a bending apparatus having a configuration such as that shown in Fig. 5 is preferably employed. In this case, the bending apparatus 30 is composed of a bending form 32, a clamp 34, a pressure 36, a restraining mandrel 38, and a wiper 40, which advantageously avoids or suppresses the occurrence of sink marks at both ends of the end processed product 6 due to bending, while advantageously avoiding or suppressing the occurrence of wrinkles at the inner bent portion of the bent portion of the end processed product 6.

[0038] Specifically, the bending form 32 has a U-shape as a whole, and its semicircular curved portion is configured as the bending portion 32a, and a rotation axis 42 is provided at the center of the semicircular shape so that the bending form 32 can be rotated around this rotation axis 42. A bending groove 32b having a semicircular cross-sectional shape is provided on the outer circumferential surface of the semicircular bending portion 32a of the bending form 32 to accommodate the bending portion of the end processed product 6 and to bend and deform it, and a bending form-side accommodating portion 32c having a larger semicircular cross-sectional shape is provided so as to communicate with this bending groove 32b to accommodate one end side portion including one annular bulge (first) 4a of the end processed product 6. By rotating the bending form 32 around the rotation axis 42, the bending portion located between the annular bulges 4a, 4b at both ends of the end processed product 6 introduced into the bending groove 32b can be bent and deformed along the bending groove 32b.

[0039] The clamp 34 also has a stepped clamp-side accommodating portion 34a for accommodating one end portion, including one annular bulge 4a, of the end processed product 6. The clamp-side accommodating portion 34a is composed of a large-diameter groove 34a1 with a semicircular cross-section large enough to accommodate one annular bulge 4a of the end processed product 6, and a small-diameter groove 34a2 with a semicircular cross-section large enough to accommodate the tubular portion of the end processed product 6. When the clamp 34 is placed over the bending form 32, the end portion, including one annular bulge 4a, of the end processed product 6 is clamped and fixed between the bending form-side accommodating portion 32c of the bending form 32 and the clamp-side accommodating portion 34a of the clamp 34, and the clamp 34 is capable of rotating integrally with the bending form 32 around the rotation axis 42.

[0040] Furthermore, the press 36 accommodates the other end portion including the other annular bulge (second) 4b from the bent portion of the end processed product 6, and while abutting against the end face of the other end portion to restrict its axial movement, presses the end processed product 6 axially toward the bent portion as the bending of the end processed product 6 progresses. The press 36 has a cylindrical portion accommodating groove 36a with a semicircular cross section that accommodates the cylindrical portion of the end processed product 6, and a slit-shaped bulge portion accommodating portion 36b that accommodates the other annular bulge 4b ​​of the end processed product 6, and further has a restraining surface 36c that abuts against the end face of the other end portion including the other annular bulge 4b ​​to restrict it. The press 36 is also configured to be pressed in the axial direction of the cylindrical portion accommodating groove 36a and toward the bent portion of the end processed product 6 (leftward in the figure) by a pressing device (not shown) located on the right side of the press 36 in Figure 5. The corresponding portions of the end processed product 6 are accommodated and held in the cylindrical portion accommodating groove 36a, the slit-shaped bulge portion accommodating portion 36b, and the restraint surface 36c of the pressure 36, and while still in a restrained state, as the bending process of the end processed product 6 progresses, the end processed product 6 is pushed axially toward the bending process portion, specifically, toward the start position of the bending process.The pushing speed of the end processed product 6 in the axial direction is generally set to be greater than the bending process speed (the speed at which the end processed product 6 is pulled axially during the bending process).

[0041] In addition, the restraining core metal 38 functions as a restraining member that prevents the end processed product 6 from moving in the axial direction, and has an accommodation recess 38a at one end thereof that accommodates one end side portion, including one annular bulge portion 4a, of the end processed product 6. The restraining core metal 38 is inserted and arranged in the clamp side accommodation portion 34a of the clamp 34 and the bending form side accommodation portion 32c of the bending form 32, and accommodates one end side portion, including the annular bulge portion 4a, accommodated in these accommodation portions 34a, 32c, in the accommodation recess 38a, and abuts against the end face of the end side portion to press the end processed product 6 in the axial direction, thereby restraining the axial movement of the end processed product 6.

[0042] Furthermore, as shown in FIG. 6, the wiper 40 has a receiving surface 44 that corresponds to the outer peripheral surface of the inner bend portion of the bent portion of the end product 6. This receiving surface 44 is accommodated in the bending groove 32b formed in the bent portion 32a of the bending form 32. The receiving surface 44 abuts against and holds the inner bend portion, thereby preventing wrinkles from occurring in the inner bend portion. Specifically, as is clear from FIGS. 6(a) to 6(d), the wiper 40 is composed of a main body 40a fixed to a predetermined stationary member and a support portion 40b replaceably attached to the main body 40a. The support portion 40b is attached to the rising portion of the main body 40a, and on its upper surface, the receiving surface 44, which corresponds to the outer peripheral surface of the inner bend portion of the bent portion of the end product 6, is formed as a groove with a semicircular cross section. The tip of the receiving surface 44 is configured as an insertion portion 46 that protrudes in a beak-like shape. In addition, the receiving surface 44 of the support portion 40b of the wiper 40 is adapted to abut against and support the inner bending portion of the end processed product 6, and the insertion portion 46 at its tip is arranged so as to fit between the end processed product 6 and the bending groove 32b in the bending form 32.

[0043] The bending of the end processed product 6 using the bending device 30 having such a configuration is carried out, for example, as shown in FIG.

[0044] The end product 6 is set on the bending device 30 as follows: One end portion of the end product 6, including the annular bulge 4a, is accommodated and fixed in the accommodation portions 32c, 34a by overlapping (mold-matching) the bending form 32 and the clamp 34, and the end portion including the annular bulge 4a is accommodated in the accommodation recess 38a provided in the restraining mandrel 38 inserted into the accommodation portions 32c, 34a and abuts against the restraining mandrel 38, thereby forming the end portion including the annular bulge 4a. On the other hand, the other end portion of the end product 6, including the annular bulge 4b ​​extending from the bending portion, is accommodated in the cylindrical portion accommodation groove 36a and the bulge portion accommodation portion 36b of the pressure member 36 provided therein, and further, the end portion on the side of the other annular bulge 4b ​​abuts against the restraining surface 36c provided on the pressure member 36, so as to be restrained. In addition, the wiper 40 is arranged in a fixed position so that the tip insertion portion 46 of the receiving surface 44 provided on its support portion 40b is inserted between the end processing product 6 and the bending processing groove 32b in the bending form 32.

[0045] When starting the bending process from the assembled state shown in Figure 7(a), as shown in Figure 7(b), the bending form 32 is rotated together with the clamp 34 around its rotation axis 42, while the pressure 36 is pressed and moved in the axial direction of the end processed product 6 toward the bending processing portion, in other words, to the left as shown by the white arrow in Figure 7(b), thereby progressing the bending process.

[0046] Thereafter, the bending form 32 is further rotated together with the clamp 34 around the rotation axis 42 by a predetermined angle (here, 90°) to complete the bending of the end part 6, and the state after this is shown in Figure 7(c). Note that during this bending process, the pressure 36 is gradually pressed and moved to the left in the figure as the bending process progresses, and is moved to its final position, and the end part 6 is bent along the bending groove 32b of the bending form 32 to form the curved pipe portion 8, resulting in the desired bent product 10.

[0047] In the bending process described above, the inner bent portion of the bent portion of the end processed product 6 is supported by the receiving surface 44 of the wiper 40, thereby effectively suppressing or preventing wrinkles from occurring in the inner bent portion. In this type of bending process, sink marks generally occur at both ends of the end processed product 6, but in this case, both ends of the end processed product 6 are restrained by being brought into contact with the bottom surface of the accommodation recess 38a of the restraining mandrel 38 and the restraining surface 36c of the pressure member 36, so that the occurrence of sink marks at both ends can be advantageously prevented.

[0048] Next, the bent product 10 obtained in this manner is removed from the bending device 30, and then processing is performed to form a third annular bulge 4c in the straight tubular portion between the curved tubular portion 8 and the other annular bulge 4b.

[0049] 8 clearly shows a vertical section of the die 50, and as shown therein, a ring-shaped forming recess 54 is formed on the inner peripheral surface of the portion of the housing portion 52 of the die 50 where the straight tubular portion of the bent product 10 is housed and positioned. On the other hand, as is clear from FIG. 8, the roller processing member 60 is formed with a ring-shaped processing protrusion 62 in a shape corresponding to the forming recess 54 provided on the inner peripheral surface of the housing portion 52 of the die 50.

[0050] The bulge forming process using the mold 50 having the forming recess 54 and the roller processing member 60 having the ring-shaped processing protrusion 62 is carried out in the same manner as in Patent No. 6,963,981, by inserting the processing portion 64 of the roller processing member 60 into the straight tubular portion of the bent product 10 as shown in FIG. 8, and then rotating and eccentricating the roller processing member 60, whereby the bulge can be easily formed by the processing portion 62 of the roller processing member 60 as shown in the figure. That is, the forming recess 52 provided on the inner peripheral surface of the accommodation portion 52 in the mold 50 and the ring-shaped processing protrusion 62 provided on the outer peripheral surface of the forming processing portion 64 of the roller processing member 60 cause the cylindrical wall portion to bulge in a ring shape, forming the third annular bulge 4c, and at the same time, the molding action between the outer peripheral surface of the forming processing portion 64 and the inner peripheral surface of the accommodation portion 52 forms the circular shape of the straight pipe portion, resulting in the formation of a straight pipe portion with a perfect circular shape, and thus the final elbow product 12 is obtained.

[0051] In the elbow product 12 obtained in this manner, annular bulges 4a, 4b are formed at both axial end portions of the straight pipe material 2, followed by bending to form a curved pipe portion 8, and then a third annular bulge 4c is formed in the straight pipe portion between the curved pipe portion 8 and the annular bulge 4b. Therefore, unlike the conventional method in which bending is performed after the formation of three annular bulges, the occurrence of pipe cracks due to work hardening can be effectively suppressed or avoided, and deformation of the annular bulge portion can also be advantageously suppressed or eliminated.

[0052] Furthermore, according to the above-described manufacturing method and manufacturing apparatus for an elbow product, the end of the bent product 10, which has the curved pipe portion 8 formed thereon, is not sheared off at the same time as the formation of the intermediate third annular bulge 4c. Therefore, there is no need to perform a further deburring process after such a process. Furthermore, during the molding process of the annular bulge, the problem of material getting into the mating surfaces of the molds and creating burr-like protrusions on the annular bulge, which reduces the shape accuracy of the annular bulge, is effectively eliminated or suppressed. As a result, the desired elbow product can be manufactured efficiently while improving the product shape. Furthermore, the process can be effectively shortened, thereby improving productivity and advantageously reducing product costs.

[0053] The elbow product 12 obtained as described above is suitable for use as a coupling component to which a hose through which a specified liquid flows is connected, such as a coupling for an oil cooler in an automotive heat exchanger. The end portion where the first annular bulge 4a is formed is fixed to the cooler body by brazing or the like, while a hose is inserted onto the straight pipe portion and its outer periphery can be fastened with a fastening band in the same manner as in the past. The presence of the two annular bulges 4b, 4c provided on the straight pipe portion prevents movement of the fastening band that secures the hose, thereby enabling effective fastening of the hose.

[0054] Although typical embodiments of the present invention have been described above in detail, it should be understood that these are merely examples and that the present invention should not be construed as being limited in any way by the specific descriptions of such embodiments.

[0055] 2 to 4, first and second annular bulges 4a, 4b are formed at both ends of the pipe material 2 in simultaneous or consecutive press processes to produce the end product 6. The annular bulges 4a, 4b can be formed using various known techniques. The two annular bulges 4a, 4b can also be formed in separate, independent processes. In these cases, various known bulging techniques can be used to form the individual annular bulges. Similarly, the third annular bulge 4c can be formed using not only the illustrated technique but also various known techniques.

[0056] Furthermore, the example elbow product 12 has a structure having a curved pipe portion 8 that is bent at an angle of approximately 90° by bending processing, but it goes without saying that the angle of the bend by the bending processing is selected appropriately depending on the final use of the elbow product 12.

[0057] Furthermore, the elbow product of the present invention is preferably used as a joint component as exemplified, but is not limited to this and can be advantageously used for various elbow products having a curved pipe section and a straight pipe section.

[0058] In addition, in the illustrated embodiment, the mold 50 is configured to have a storage section 52 in which the straight tubular portion of the bent product 10 is stored and held, but instead, it is also possible to use a mold having a storage section that can store almost the entire bent product 10 including the straight tubular portion.

[0059] Although not listed here, the present invention can be implemented in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and it should be understood that all such implementation forms fall within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0060] 2 Pipe material 4a: First annular bulge 4b: Second annular bulge 6 End processed product 8 Bent pipe part 10 Bent products 12 Elbow products 14 Mold 14L Lower Mold 16 Punch 17L Clamp body 18L Sub-clamp 20L Retaining hole 22L Clamp hole 26 Tapered hole 28 Core 30 Bending equipment 32 Bending form 32a Bending part 32b Bent groove 32c Receiving portion 34 Clamp 34 34a Receptacle 36 Pressure 36a Cylindrical part accommodation groove 36b Bulge housing portion 36c Restriction surface 38 Restraining core metal 38a Receiving recess 40 Wiper 40a Main body 40b support portion 42 rotation shaft 44 receiving surface 46 insertion portion 50 mold 52 accommodation section 54 forming recess 60 roller processing member 62 Ring-shaped processing convex portion 64 Molding processing portion

Claims

1. A method for manufacturing an elbow product having a first annular bulge located at one axial end of a pipe body, bulging outward in the radial direction and extending continuously in the circumferential direction, a second annular bulge located at the other axial end of the pipe body, bulging outward in the radial direction and extending continuously in the circumferential direction, a third annular bulge located at an intermediate axial portion of the pipe body, bulging outward in the radial direction and extending continuously in the circumferential direction, and a curved pipe portion formed between the third annular bulge and the first annular bulge and curved at a predetermined angle, comprising: preparing a straight pipe blank of a predetermined length from which the elbow product is to be made; a step of forming the first and second annular bulges at both axial end portions of the pipe material by press working the pipe material to obtain an end processed product; a step of bending a portion of the end processed product on the side where the first annular bulge portion is formed to obtain a bent product having the curved pipe portion formed by bending the end processed product at a predetermined angle; forming the third annular bulge portion in a straight pipe portion of the bent product between the bent pipe portion and the second annular bulge portion; A method for manufacturing an elbow product, comprising:

2. 2. The method for manufacturing an elbow product according to claim 1, wherein the press working of the pipe material is carried out by pressing the pipe material in the axial direction to bulge the pipe wall portion radially outward, and the first and second annular bulges are formed at the end portions on both axial sides of the pipe material, respectively.

3. 2. The method for manufacturing an elbow product according to claim 1, wherein one end portion of the end processed product including the first annular bulge portion is fixed and held, while the other end portion of the end processed product including the second annular bulge portion is restrained, and a bending processing portion located between the first annular bulge portion and the second annular bulge portion of the end processed product is bent and deformed, and as the bending deformation progresses, the end processed product is pushed axially toward the bending processing portion, thereby bending the end processed product.

4. 4. A method for manufacturing an elbow product according to claim 3, further comprising the steps of: using a bending form having a semicircular bending portion, a pivot shaft provided at the center of the semicircular shape of the bending portion, and a bending groove having a semicircular cross section provided along the outer periphery of the bending portion; rotating the bending form about the pivot shaft to bend and deform the bending portion of the end processed product introduced into the bending groove; and inserting a wiper member having a receiving surface corresponding to the outer periphery of the inner bend portion of the bending portion between the bending groove and the inner bend portion of the bending portion, so that the receiving surface of the wiper member abuts against and holds the inner bend portion of the bending portion, thereby preventing wrinkles from occurring in the inner bend portion.

5. 2. The method for manufacturing an elbow product according to claim 1, wherein the third annular bulge is formed by rotating a roller processing member inserted and positioned within the pipe of the bent product while pressing the inner surface of the pipe, thereby bulging the pipe wall radially outward.

6. 6. A method for manufacturing an elbow product according to any one of claims 1 to 5, characterized in that the elbow product is a coupling part to which a hose for circulating a predetermined fluid is connected, and a straight pipe section between the curved pipe section and the second annular bulge section is configured as a hose connection part of the coupling part.

7. An apparatus for manufacturing an elbow product having a first annular bulge located at one end of a pipe in the axial direction, bulging outward in the radial direction and extending continuously in the circumferential direction, a second annular bulge located at the other end of the pipe in the axial direction, bulging outward in the radial direction and extending continuously in the circumferential direction, a third annular bulge located at an intermediate portion of the pipe in the axial direction, bulging outward in the radial direction and extending continuously in the circumferential direction, and a curved pipe portion formed between the third annular bulge and the first annular bulge and curved at a predetermined angle, a press processing device that presses a straight pipe material of a predetermined length to form the first and second annular bulges at both axial end portions of the pipe material, thereby producing an end processed product; a bending device that bends a portion of the end processed product on the side where the first annular bulge portion is formed, to form a bent product having the curved pipe portion bent at a predetermined angle; a bulge forming device for forming the third annular bulge portion in a straight pipe portion between the bent pipe portion and the second annular bulge portion in the bent product; An apparatus for manufacturing an elbow product, comprising:

8. The bending device is a bending form having a semicircular bending portion, a rotation axis provided at the center of the semicircular shape of the bending portion, and a bending groove having a semicircular cross section provided along the outer circumferential surface of the bending portion, the bending form bending a bending portion located between the first annular bulge portion and the second annular bulge portion of the end processed product introduced into the bending groove by rotating the bending form around the rotation axis; a clamp member that is placed over the bending form to clamp one end portion of the end processed product including the first annular bulge between the bending form and the clamp member, and that is rotated together with the bending form in a fixed state; a pressure member that receives the other end portion including the second annular bulge from the bending portion of the end processed product, and abuts against the end face of the other end portion to restrict its axial movement, and presses the end processed product in the axial direction toward the bending portion as the bending of the end processed product progresses; The method for manufacturing an elbow product according to claim 7, further comprising the steps of:

9. The method for manufacturing an elbow product according to claim 8, further comprising a restraining member that abuts against and restrains an end surface of one end side portion of the end processed product, including the first annular bulge portion, which is clamped between the bending form and the clamp member, thereby preventing axial movement of the end processed product.

10. 10. A manufacturing method for an elbow product according to claim 8 or claim 9, characterized in that a wiper member is disposed between the end processed product and the bending groove in the bending form, the wiper member having a receiving surface corresponding to the outer peripheral surface of the inner bend portion of the bent portion of the end processed product, the wiper member abutting and supporting the inner bend portion with the receiving surface to prevent wrinkles from occurring in the inner bend portion.

Images