JP2004114062A - Hydrostatic forming method and structure for supporting end of work used in hydrostatic forming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrostatic forming method by which excessive pulling-in of the end part of a tubular work in toward the middle area in the length direction of the axis of a work is restrained when performing hydrostatic forming and the supporting structure of the end of the work used in the hydrostatic forming. <P>SOLUTION: A means for transmitting the direction change of pressure receiving force is arranged on the side of the inside wall surface 20i of the end part 20 of the tubular work 2 by using the means for transmitting the direction change of pressure receiving force having a pressure receiving body 3 having a pressure receiving surface 34 and a work restraining body 4 having a restraining surface 42. The restraining property of the end part 20 of the tubular work 2 is raised by pressurizing the restraining surface 42 of the work restraining body 4 along the outward direction ( the direction of the arrow Y1 ) of the diameter of the tubular work 2 against the inside wall surface of the end part of the tubular work 2 by receiving the liquid pressure of the hollow chamber 21 of the tubular work 2 by the pressure receiving surface 34 of the pressure receiving body 3 and also changing the direction of the receiving force received by the pressure receiving surface 34 as force in the outward direction of the diameter of the tubular work 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic forming method for forming a tubular workpiece by using a hydraulic pressure in a hollow chamber of the tubular workpiece, and a work terminal support structure used for the hydraulic forming.
[0002]
[Prior art]
In recent years, development of a hydraulic forming method for forming a tubular work by applying a hydraulic pressure to a hollow chamber of the tubular work has been advanced. According to such hydraulic forming, conventionally, as shown in FIG. 11, a plug member 100 having a seal member 101 on an outer peripheral portion and having a liquid injection hole 102 is connected to the inner wall surface of the shaft end portion 20 of the tubular workpiece 2. In this state, the pressure liquid L is supplied from the liquid injection hole 102 to the hollow chamber 21 of the tubular workpiece 2 and the tubular workpiece 2 is formed using the liquid pressure of the hollow chamber 21 of the tubular workpiece 2. Have been. The sealing member 101 of the plug member 100 can suppress liquid leakage from the hollow chamber 21 of the tubular workpiece 2.
[0003]
As shown in FIG. 12, a forming die 300 having a forming die surface 301 for forming the tubular workpiece 2 and a conical expanding surface 302 expanding from an end of the forming die surface 301 is provided. When the tubular work 2 is set on the mold 300 using the base 400 having a conical engaging surface 401 that engages with the surface 302, the shaft end of the tubular work 2 is moved from the mold surface 301 of the mold 300. In this state, the engaging surface 401 of the base 400 is applied to the shaft end 20 of the tubular work 2, and the shaft end 20 of the tubular work 2 is expanded in a conical shape to support the terminal. A terminal sealing method in bulging is also known (see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-6-23441
[0005]
[Problems to be solved by the invention]
According to the conventional technique shown in FIG. 11, the shaft end 20 of the tubular workpiece 2 may be pulled in the direction of the central region in the axial direction of the tubular workpiece 2 (the direction of arrow X2) during the hydroforming. Moreover, the amount of pull-in tends to vary depending on the material of the tubular workpiece 2, the roundness, and the like. For this reason, there is a limit to further increasing the molding accuracy of the hydraulic molding.
[0006]
Further, according to the conventional technique shown in FIG. 12, the liquid pressure of the pressure liquid supplied to the hollow chamber 21 of the tubular work 2 urges the base 400 in a direction of detaching the base 400 from the tubular work 2 (the direction of the arrow X1). Therefore, as the liquid pressure in the hollow chamber 21 of the tubular work 2 increases, the base 400 is urged in a direction in which the base 400 separates from the tubular work 2 (the direction of the arrow X1), and the base 400 is moved toward the shaft end 20 of the tubular work 2. May be loosened. For this reason, if the liquid pressure in the hollow chamber 21 of the tubular work 2 increases, there is a possibility that the forming of the tubular work 2 may be hindered.
[0007]
The present invention has been made in view of the above-described circumstances, and it is possible to suppress the shaft end of a tubular workpiece from being excessively drawn toward a central region in the axial direction of the workpiece during hydraulic forming. It is an object of the present invention to provide a hydraulic molding method capable of favorably performing molding, and a work terminal support structure used for hydraulic molding.
[0008]
[Means for Solving the Problems]
(1) A hydraulic forming method according to the present invention is directed to a hydraulic forming method for forming a tubular workpiece by applying a hydraulic pressure to a hollow chamber of the tubular workpiece.
The tubular work has a pressure receiving surface facing the hollow chamber and a constraining surface facing the inner wall surface of the shaft end of the tubular work, and receives the pressure received by the pressure receiving surface in a radially outward direction of the tubular work. Using a pressure-receiving direction change transmission means that changes direction and transmits as a force along,
The receiving pressure direction change transmission means is disposed on the inner wall surface side of the shaft end of the tubular work,
During the forming of the tubular work, the liquid pressure in the hollow chamber of the tubular work is received by the pressure receiving surface of the pressure receiving direction change transmission unit, and the pressure received by the pressure receiving surface is reduced by the diameter of the tubular work. The direction is changed as a force along the outward direction, and the constraining surface of the pressure receiving direction change transmitting means is pressed against the inner wall surface of the shaft end of the tubular work along the radially outward direction of the tubular work. The present invention is characterized in that the restricting property of the shaft end of the tubular work is enhanced.
[0009]
ADVANTAGE OF THE INVENTION According to the hydraulic forming method which concerns on this invention, at the time of shaping | molding a tubular workpiece, the hydraulic pressure of the hollow chamber of a tubular workpiece is received by the pressure receiving surface of the pressure receiving direction change transmission means. The direction of the pressure received by the pressure receiving surface is changed along the radial direction of the tubular work, and the restraining surface of the pressure receiving direction change transmission means is formed on the inner wall surface of the shaft end of the tubular work in the radial direction of the tubular work. Pressurized along. Thereby, the constraint of the shaft end of the tubular work is enhanced, and excessive pulling of the shaft end of the tubular work is suppressed.
[0010]
(2) The work terminal supporting structure used for hydraulic forming according to the present invention is disposed on the inner wall surface side of the shaft end of the tubular work, and receives a hydraulic pressure in the hollow chamber of the tubular work; A pressure-receiving body having an outer inclined surface having a taper whose diameter decreases as it goes toward the shaft tip in the axial direction of the work,
An inner side which is disposed on the inner peripheral surface side of the shaft end of the tubular work, engages with the outer inclined surface of the pressure receiving body, and has a taper whose diameter decreases toward an axial front end of the tubular work in the axial direction. A work restraint body having an inclined surface and a restraint surface that faces the inner wall surface of the shaft end of the tubular work and presses and restrains the inner wall surface of the shaft end of the tubular work in a radially outward direction. And characterized in that:
[0011]
According to the work terminal support structure used in the hydraulic forming according to the present invention, in forming the tubular work, the pressure in the hollow chamber of the tubular work is received by the pressure receiving surface of the pressure receiving body. It is urged toward the shaft tip of the tubular workpiece. Since the outer inclined surface of the pressure receiver engages with the inner inclined surface of the work restraint, the pressure applied by the pressure receiver to the hydraulic pressure by the so-called wedge principle causes the restraining surface of the work restraint to move outside the diameter of the tubular workpiece. The direction is changed as a force for urging along the direction. As a result, the restraining surface of the work restraint presses the inner wall surface at the axial end of the tubular work along the radially outward direction of the tubular work. Thereby, the constraint of the shaft end of the tubular work is enhanced, and excessive pulling of the shaft end of the tubular work is suppressed.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the present invention, the pressure-receiving direction change transmitting means has a pressure-receiving surface facing the hollow chamber of the tubular work and a restraining surface facing the inner wall surface of the shaft end of the tubular work. The received pressure is changed in direction as the force along the radial direction of the tubular workpiece and transmitted. The pressure receiving direction change transmission means can be formed by a plurality of components. For example, the pressure receiving direction change transmitting means includes a pressure receiving body having a pressure receiving surface for receiving the liquid pressure in the hollow chamber of the tubular work, and a work restraining surface having a restraining surface for pressing and restraining the inner wall surface of the shaft end of the work. It can be formed with the body.
[0013]
According to the present invention, preferably, a form in which a regulating member for regulating movement of the work restricting body toward the shaft tip of the tubular work can be adopted. In this case, the movement of the work restricting member toward the shaft tip of the tubular work is restricted by the restricting member. For this reason, the work restraint is satisfactorily urged along the radial direction of the tubular work, and thus the restraining surface of the work restraint is satisfactorily placed on the inner wall surface of the shaft end of the tubular work along the radial direction of the tubular work. It can be pressurized.
[0014]
According to the present invention, preferably, the outer inclined surface of the pressure receiving member is formed in a circumferential direction around the axis of the pressure receiving member, and the inner inclined surface of the work restraint is preferably formed around the axis of the work restricting member. The form formed in the direction can be adopted. As a result, the work restraint is satisfactorily urged along the radially outward direction of the tubular work, and thus the restraining surface of the work restraint is favorably placed on the inner wall surface of the shaft end of the tubular work along the radially outward direction of the tubular work. It can be pressurized.
[0015]
According to the present invention, preferably, the work restraining body is formed of a plurality of divided bodies in the circumferential direction of the work restraining body, and each divided body adopts a form having an inner inclined surface and a restraining surface. it can. Since each divided body is divided in the circumferential direction, it can operate independently of each other along the radially outward direction. Therefore, even when the roundness of the cross-sectional shape of the tubular workpiece is low, or even when it is not a perfect circular shape, each of the divided bodies constituting the work restraint is independently formed along the radial direction. It can be urged, whereby the restraining surface of the divided body constituting the work restraining body can be satisfactorily pressed against the inner wall surface of the shaft end of the tubular work along the radially outward direction of the tubular work.
[0016]
According to the present invention, preferably, a form in which a stretchable cord is attached to each of the divided bodies of the work restraining body and the divided bodies are connected to each other by the cord can be adopted. Thereby, separation of each divided body is suppressed, and the divided bodies are suitable for storage and attachment. Examples of the cord body include a rubber ring, a stretchable rope, and a stretchable wire.
[0017]
According to the present invention, preferably, the restraint surface of the work restraint body may have a form having an engagement degree increasing portion for increasing the engagement with the inner wall surface of the shaft end of the tubular work. Thereby, the retraction of the shaft end of the tubular work is further suppressed. At least one of a concave and a convex can be adopted as the engagement degree increasing portion. Examples of the engagement degree increasing portion include a mode in which the engagement portion is engaged with the inner wall surface of the shaft end of the tubular work.
[0018]
According to the present invention, the work restraint can be formed of a metal material or a ceramic material. In some cases, the work restraint can be formed of an elastically deformable material based on rubber or resin.
[0019]
【Example】
Hereinafter, a first embodiment of the present invention will be specifically described with reference to FIGS. This embodiment is applied to a case where bending forming, that is, bend forming is performed on a metal tubular workpiece 2. Prebend molding is a type of hydraulic molding, similar to hydroform molding. The prebend molding is performed prior to the hydroform molding in which the peripheral wall 2a of the tubular work 2 is expanded by applying a hydraulic pressure to the hollow chamber 21 of the tubular work 2. In the pre-bend molding, the tubular workpiece 2 is placed in a molding cavity 13 formed by the first mold surface 15 of the first mold 11 of the mold 1 and the second mold surface 16 of the second mold 12. This is performed by bending an intermediate portion (not shown) of the work 2 in the axial length direction.
[0020]
First, the device will be described for convenience of description. According to the present embodiment, as shown in FIG. 1, the pressure receiving body 3 and the work restraining body 4 are provided. The pressure receiving body 3 and the work restraining body 4 constitute a pressure receiving direction change transmission unit that converts the pressure received by the pressure receiving body 3 as a force along the radial direction. The pressure receiving member 3 is formed of a metal material or a ceramic material, and is set in the molding cavity 13 of the molding die 1 so as to be disposed on the inner wall surface 20i side of the shaft end portion 20 of the tubular workpiece 2.
[0021]
The pressure receiving member 3 is disposed on the inner wall surface 20i side of the shaft end portion 20 of the tubular work 2, and controls the pressure P of the pressure liquid L (water or oil) supplied to the hollow chamber 21 of the tubular work 2. It receives pressure. The pressure receiving body 3 is opposed to the hollow chamber 21 of the tubular workpiece 2 and has a relatively large outer diameter. A large-diameter section 30 is formed on the side of the tubular workpiece 2 opposite to the hollow chamber 21 and is larger than the large-diameter section 30. The small diameter portion 32 has a relatively small outer diameter.
[0022]
The distal end of the large-diameter portion 30 of the pressure receiving body 3 is a pressure receiving surface 34 that faces the hollow chamber 21 of the tubular workpiece 2 and receives the hydraulic pressure P in the hollow chamber 21. The pressure receiving surface 34 extends along a direction perpendicular to the axis of the pressure receiving body 3. A ring 34 is formed on the outer edge of the pressure-receiving surface 34 such that a diameter-reduced surface 34c whose diameter decreases toward the hollow chamber 21 of the tubular workpiece 2 makes a round around the axis of the pressure-receiving body 3 as a part of the pressure-receiving surface 34. It is formed in a shape. When the hydraulic pressure P in the hollow chamber 21 of the tubular workpiece 2 acts on the reduced-diameter surface 34c of the pressure receiving body 3, a force in the centripetal direction acts on the pressure receiving body 3, so that the centering action of the pressure receiving body 3 is expected. it can.
[0023]
FIG. 2 shows a side surface of the pressure receiver 3. As shown in FIG. 2, the small diameter portion 32 of the pressure receiving body 3 has the same diameter in the axial direction of the pressure receiving body 3. An outer inclined surface 33 is formed between the large diameter portion 30 and the small diameter portion 32 of the pressure receiving body 3. As shown in FIG. 1, the outer inclined surface 33 has a conical surface shape having a straight taper whose diameter decreases toward the axial end 2 e of the tubular workpiece 2 in the axial direction. In addition, a passage 35 communicating with the hollow chamber 21 of the tubular workpiece 2 is formed in the pressure receiving body 3, and a projection 36 projecting in a direction opposite to the hollow chamber 21 of the tubular workpiece 2 is connected to the pressure receiving body 3.
[0024]
As shown in FIG. 1, the work restricting body 4 is formed using a metal material or a ceramic material as a base material, is disposed on the inner wall surface 20i side of the shaft end portion 20 of the tubular work 2, and fixes the peripheral wall 2 a of the tubular work 2. It is for restraint. The work restraining body 4 includes an inner inclined surface 41 facing the outer inclined surface 33 of the pressure receiving body 3, a restraining surface 42 formed on the outer peripheral surface, a first shaft end surface 43 facing the large diameter portion 30, and a tubular workpiece. And a second shaft end face 44 located on the opposite side of the second hollow chamber 21. The inner inclined surface 41 of the work restricting body 4 is engaged with the outer inclined surface 33 of the pressure receiving body 3 and has a taper whose diameter decreases toward the axial end 2 e of the tubular work 2 in the axial direction. The inner inclined surface 41 of the work restricting body 4 has basically the same taper angle as the outer inclined surface 33 of the pressure receiving body 3. The restraining surface 42 of the work restraint 4 faces the inner wall surface 20i of the shaft end 20 of the tubular work 2, and extends along the axis of the work restraint 4. The constraining surface 42 is for pressing and constraining the inner wall surface 20i of the shaft end 20 of the tubular workpiece 2 along the radially outward direction (the direction of the arrow Y1).
[0025]
According to the present embodiment, as shown in FIG. 1, the regulating member 5 that regulates the movement of the work restricting body 4 toward the shaft tip 2 e of the tubular work 2 (the direction of the arrow X <b> 1) is provided. The regulating member 5 is inserted between the first molding die 11 (upper die) and the second molding die 12 (lower die). The regulating member 5 has an insertion tip 51 inserted into the shaft end opening 20r of the shaft end 20 of the tubular workpiece 2, and a hollow portion 52 formed in the center region and extending in the axial direction. The insertion distal end portion 51 has a guide hole 53 having a guide wall surface 53 a for guiding and sliding the small-diameter portion 32 of the pressure receiving body 3, and a distal end regulating surface 54 facing the second shaft end surface 44 of the work restricting body 4. . The tip regulating surface 54 has a ring shape, and extends along a direction perpendicular to the axis of the work restricting body 4. The guide wall surface 53a extends along the axial direction of the work restricting body 4. In a state where the second shaft end surface 44 of the work restricting member 4 is in contact with the ring-shaped tip restricting surface 54 of the restricting member 5, the work restricting member 4 cannot further retreat toward the restricting member 5 (in the direction of the arrow X <b> 1). Therefore, the operation is performed in the radially outward direction (the direction of the arrow Y1).
[0026]
As shown in FIG. 1, a spring member 38 and a protrusion 36 are provided in the hollow portion 52 of the regulating member 5. The spring member 38 urges the pressure receiver 3 toward the hollow chamber 21 of the tubular member 2 (in the direction of the arrow X2) via the seat 36c of the projection 36 to set the pressure receiver 3 at its original position. It is.
[0027]
FIG. 3 shows a front view of the work restraint 4. As shown in FIG. 3, the work restraint 4 is formed of a plurality of (six) divided bodies 46 in the circumferential direction of the work restraint 4. The divided body 46 is basically shaped like a fan. Each of the divided bodies 46 has an inner inclined surface 41 and a restraining surface 42, respectively, and has a radially divided surface 47. In a normal state, the divided surfaces 47 of the adjacent divided bodies 46 constituting the work restricting body 4 are attracted by the elastic contracting force of the below-described cord 49, and are in contact with each other or approach each other. ing. However, when a force in the radially outward direction (direction of arrow Y1) acts on each of the divided bodies 46, each of the divided bodies 46 operates in the radially outward direction (direction of arrow Y1). Are separated from each other against the elastic contraction force of the cord body 49.
[0028]
FIG. 4 shows a cross-sectional view of the work restraint 4. As shown in FIGS. 4 and 3, a ring groove 49 a extending in the circumferential direction is formed on the constraint surface 42, which is the outer peripheral surface of the work constraint body 4. In the ring groove 49a, a rope-shaped cord 49 made of a ring-shaped elastic material such as elastic rubber or resin as a base material is wound and attached. The divided bodies 46 are connected to each other and integrated by the elastic contracting force of the cord body 49, and are not separated from each other during storage or mounting.
[0029]
According to the present embodiment, as shown in FIG. 1, a ring-shaped first seal groove 61c is formed on the outer peripheral surface of the large diameter portion 30 of the pressure receiving member 3, and the ring-shaped first seal groove 61c is formed in the first seal groove 61c. The first seal member 61 is provided. A ring-shaped second seal groove 62c is formed on the outer peripheral surface of the small-diameter portion 32 of the pressure receiving member 3, and a ring-shaped second seal member 62 is provided in the second seal groove 62c. The first seal member 61 and the second seal member 62 are arranged before and after the work restrictor 4 in the axial direction of the work restrictor 4. As a result, the first and second seal members 61 and 62 seal the front and rear of the work restrictor 4 in the axial direction of the work restrictor 4. Therefore, the flow of the pressure liquid L in the hollow chamber 21 of the tubular workpiece 2 toward the workpiece constraint 4 is suppressed.
[0030]
Next, the case of performing hydraulic forming will be described. First, as shown in FIG. 1, the tubular workpiece 2 is set in the molding cavities 13 of the first molding tool 11 and the second molding tool 12 of the molding tool 1. The pressure receiving body 3 and the work restricting body 4 are arranged on the wall surface 20i side. In this case, the structure shown in FIG. 1 may be employed only at one axial end 20 of the tubular workpiece 2 in the axial direction, or may be employed at both axial ends 20 of the tubular workpiece 2 in the axial direction. It may be. In the former case, a general plug member is attached to the other shaft end 20 in the axial direction of the tubular workpiece 2.
[0031]
With the pressure receiving member 3 and the work restricting member 4 attached to the inner wall surface 20i side of the shaft end portion 20 in the axial direction of the tubular work 2 as described above, the pressure liquid L (water) is supplied from the liquid supply source 7 (pump or the like). Or the like) is supplied to the hollow chamber 21 of the tubular workpiece 2 through the cavity 52 of the regulating member 5 and the passage 35 of the pressure receiving body 3. In this case, it is preferable to deaerate the air in the hollow chamber 21 of the tubular workpiece 2. With the hollow chamber 21 of the tubular workpiece 2 kept at the predetermined hydraulic pressure P in this manner, the tubular workpiece 2 is subjected to bending. At this time, the axial end portion 20 of the tubular work 2 is not drawn in the direction of the arrow X2 toward the central region of the tubular work 2 in the axial direction.
[0032]
In this respect, according to the present embodiment, the pressure receiving surface 3 of the pressure receiving member 3 receives the hydraulic pressure P in the hollow chamber 21 of the tubular workpiece 2, so that the pressure receiving member 3 has a tubular shape against the elastic force of the spring member 38. The work 2 is displaced by being urged toward the shaft tip 2e (in the direction of arrow X1). In this case, the small diameter portion 32 of the pressure receiving body 3 is displaced in the direction of the arrow X1 along the guide wall surface 53a of the guide hole 53. Here, since the outer inclined surface 33 of the pressure receiver 3 is engaged with the inner inclined surface 41 of the work restraining member 4, the pressure receiving surface 34 of the pressure receiver 3 receives the hydraulic pressure P of the hollow chamber 21 of the tubular workpiece 2. The received pressure is changed in direction as a force for urging the constraining surface 42 of the work restricting body 4 in a radially outward direction of the tubular work 2 (direction of the arrow Y1) according to a so-called wedge principle. Therefore, the restraining surface 42 of the work restraining body 4 is pressed in a radially outward direction of the tubular workpiece 2 (the direction of the arrow Y1). As a result, the restraining property of the shaft end 20 of the tubular work 2 is enhanced, and excessive pulling of the shaft end 20 of the tubular work 2 in the direction of arrow X2 is suppressed. As the liquid in the hollow chamber 21 of the tubular workpiece 2 increases, the pressure received by the pressure receiving surface 34 of the pressure receiving body 3 increases, so that the restraining force by the restraining surface 42 increases, and the shaft end 20 of the tubular workpiece 2 Restraint is enhanced.
[0033]
According to the present embodiment, during molding, as described above, excessive retraction of the shaft end 20 of the tubular workpiece 2 can be suppressed, and even if the retraction is performed, it can be suppressed to a constant amount. Can be suppressed, and the hydraulic forming of the tubular workpiece 2 can be favorably performed. According to the present embodiment, the restraining force of the restraint surface 42 of the work restraint 4 can be adjusted by the taper angle of the outer inclined surface 33 of the pressure receiving body 3 and the inner slope 41 of the work restraint 4.
[0034]
Although the tubular workpiece 2 which is an industrial product is in the shape of a pipe, there is a limit to improving the roundness of the cross-sectional shape with high accuracy. In this regard, according to the present embodiment, as described above, the work restricting body 4 is formed by the divided bodies 46 divided into a plurality in the circumferential direction of the work restricting body 4, and is independent of each other in the radially outward direction ( (Along arrow Y1). Therefore, even when the roundness of the cross-sectional shape of the tubular work 2 is low, each of the divided bodies 46 can be independently urged along the radially outward direction, thereby constituting the work restraining body 4. The constraining surface 42 of the divided body 46 can be satisfactorily pressed against the inner wall surface 20i of the shaft end 20 of the tubular work 2 along the radially outward direction of the tubular work 2 (the direction of the arrow Y1). The restraint of the end 20 can be ensured.
[0035]
According to this embodiment, the pressure liquid L also flows into the guide hole 53 of the regulating member 5. The pressure liquid L flowing into the guide hole 53 may act on the small-diameter end surface 32k of the small-diameter portion 32 of the pressure receiving body 3 to generate a force directed in the direction of the arrow X2. In this regard, according to the present embodiment, if the pressure receiving area of the pressure receiving surface 34 of the large diameter portion 30 of the pressure receiving member 3 is S1, and the pressure receiving area of the small diameter end surface 32k of the small diameter portion 32 of the pressure receiving member 3 is S2, S1 is S2 It is set to be much larger than (S1> S2). For this reason, even if the pressure liquid L flows into the guide hole 53 of the regulating member 5, the pressure receiver 3 can be favorably moved toward the work restricting member 4 (in the direction of the arrow X <b> 1).
[0036]
According to the present embodiment, as the restraining force by the restraining surface 42 of the work restraining body 4, the pressure receiving area S1 of the pressure receiving surface 34 of the large diameter portion 30 of the pressure receiving member 3 and the pressure receiving area S2 of the small diameter end surface 32k of the small diameter portion 32 are used. It can also be adjusted by changing the ratio.
[0037]
According to the present embodiment, as shown in FIG. 1, the first seal member 61 and the second seal member 62 are provided before and after the work restricting body 4, and the work restricting body 4 extends in the axial direction. The front and rear sides of the restricting body 4 are sealed by a first seal member 61 and a second seal member 62. Therefore, the flow of the pressure liquid L in the hollow chamber 21 and the guide hole 53 of the tubular work 2 toward the work restricting body 4 is suppressed. Therefore, it is ensured that the divided body 46 of the work restricting body 4 moves outward in the radial direction (the direction of the arrow Y1). Consequently, good restraint of the shaft end 20 of the tubular workpiece 2 is ensured.
[0038]
Further, according to the present embodiment, since the regulating member 5 for regulating the movement of the work restricting member 4 toward the shaft tip 2e of the tubular work 2 is provided, the work restricting member 4 is moved to the axial end of the tubular work 2. The movement toward 2e (in the direction of arrow X1) is restricted by the restriction member 5. Therefore, when the pressure receiving body 3 is displaced in the direction of the arrow X1, the work restraining body 4 is urged satisfactorily along the radially outward direction of the tubular work 2 (the direction of the arrow Y1), and the restraining surface 42 of the work restraining body 4 is thus tubular. The inner wall surface 20i of the shaft end 20 of the work 2 can be satisfactorily pressed along the radially outward direction of the tubular work 2 (the direction of the arrow Y1).
[0039]
Further, according to the present embodiment, a stretchable cord 49 is wound around each of the divided bodies 46 of the work restraining body 4, and the divided bodies 46 are connected to each other by the cord 49. Thereby, detachment of each divided body 46 is suppressed, and the divided body 46 is suitable for storage and attachment.
[0040]
(Second embodiment)
FIG. 5 shows a second embodiment of the present invention. This embodiment has basically the same configuration as the above-described first embodiment, and basically has the same operation and effect. Hereinafter, a description will be given focusing on portions different from the first embodiment. According to the present embodiment, the engagement surface increasing portion 64 that increases the engagement with the inner wall surface 20i of the shaft end portion 20 of the tubular workpiece 2 is formed on the constraint surface 42 that is the outer peripheral surface of the workpiece constraint body 4. ing. The engagement degree increasing portion 64 is formed by an uneven portion. The concave and convex portions extend along the circumferential direction of the constraint surface 42 of the work constraint body 4. Therefore, when the restraining surface 42 of the work restraining body 4 is pressed in a radially outward direction (the direction of the arrow Y1) of the tubular work 2, the engagement degree increasing portion 64 engages with the inner wall surface 20 i of the shaft end 20 of the tubular work 2. Engaging performance is increased. For this reason, the restraining property of the shaft end 20 of the tubular work 2 is enhanced, and the drawing in of the shaft end 20 of the tubular work 2 is further suppressed.
[0041]
(Third embodiment)
FIG. 6 shows a third embodiment of the present invention. This embodiment has basically the same configuration as the above-described first embodiment, and basically has the same operation and effect. Hereinafter, a description will be given focusing on portions different from the first embodiment. According to the present embodiment, the engagement surface increasing portion 64 </ b> B that increases the engagement with the inner wall surface 20 i of the shaft end portion 20 of the tubular workpiece 2 is formed on the constraint surface 42 of the workpiece constraint body 4. The engagement degree increasing portion 64B is formed of a concave-convex portion having a convex portion with a sharp outer end. The concave and convex portions extend along the circumferential direction of the constraint surface 42 of the work constraint body 4. When the restraining surface 42 of the work restraining body 4 is pressed in a radially outward direction (the direction of the arrow Y1) of the tubular work 2, the engagement degree increasing portion 64B engages with the inner wall surface 20i of the shaft end 20 of the tubular work 2. Since the compatibility is enhanced, the restraining property of the shaft end 20 of the tubular work 2 is enhanced, and the drawing in of the shaft end 20 of the tubular work 2 is further suppressed. Even if the drawing-in occurs, even if the drawing-in occurs, it can be suppressed to a constant amount, so that the variation in the drawing-in amount can be suppressed, and the tubular workpiece 2 can be formed favorably.
[0042]
(Fourth embodiment)
FIG. 7 shows a fourth embodiment of the present invention. This embodiment has basically the same configuration as the above-described first embodiment, and basically has the same operation and effect. Hereinafter, a description will be given focusing on portions different from the first embodiment. According to the present embodiment, the cross section of the tubular workpiece 2B is not a perfect circle but an ellipse. Therefore, the front shape of the work restricting body 4B arranged on the inner wall surface 20i side of the shaft end portion 20 of the tubular work 2B is also an oval shape corresponding to the tubular work 2B.
[0043]
Also in the present embodiment, the work restricting body 4B is formed by a divided body 46B divided into a plurality in the circumferential direction of the work restricting body 4B. Each of the divided bodies 46B can move along the radial direction independently of each other. Therefore, since each of the divided bodies 46B constituting the work restricting body 4B can be independently biased in the radially outward direction, even when the cross-sectional shape of the tubular work 2B is an elliptical shape, The constraining surface 42 of the divided body 46B can be satisfactorily pressed against the inner wall surface 20i of the shaft end 20 of the tubular work 2B, and the restraint of the shaft end 20 of the tubular work 2B can be ensured.
[0044]
(Fifth embodiment)
FIG. 8 shows a fifth embodiment of the present invention. This embodiment has basically the same configuration as the above-described first embodiment, and basically has the same operation and effect. Hereinafter, a description will be given focusing on portions different from the first embodiment. According to the present embodiment, the cross section of the tubular workpiece 2C has a square shape. Therefore, the front shape of the work restricting body 4C disposed on the inner wall surface 20i side of the shaft end portion 20 of the tubular work 2C is also a square shape corresponding to the tubular work 2C.
[0045]
Also in the present embodiment, the work restricting body 4C is formed of a plurality of divided bodies 46C divided in the circumferential direction of the work restricting body 4C, and can move independently of each other along the radial direction. Therefore, since each of the divided bodies 46C constituting the work restricting body 4C can be independently urged in the radially outward direction, even when the cross-sectional shape of the tubular work 2C is a quadrangular shape, each divided body 46C is divided into squares. The restraining surface 42 of the body 46C can be satisfactorily pressed against the inner wall surface 20i of the shaft end 20 of the tubular work 2C, and the restraint of the shaft end 20 of the tubular work 2C can be ensured.
[0046]
(Sixth embodiment)
FIG. 9 shows a sixth embodiment of the present invention. This embodiment has basically the same configuration as the above-described first embodiment, and basically has the same operation and effect. Hereinafter, a description will be given focusing on portions different from the first embodiment. According to the present embodiment, the work restricting body 4D is integrally formed in a ring shape using rubber or resin as a base material, and is continuous so as to make one round in the circumferential direction. The work restraining body 4D has an inner inclined surface 41 and a restraining surface 42, and has a first shaft end surface 43 and a second shaft end surface 44. Since the work restraining body 4D is formed integrally and is continuous in the circumferential direction, unlike the first embodiment, there is no need to integrate the work restraining body 4 with the ring-shaped cable body 49. Therefore, the cable body 49 is provided. Absent.
[0047]
Also in this embodiment, when the pressure receiving body 3 and the work restraining body 4D are attached to the inner wall surface 20i side of the shaft end portion 20 in the axial direction of the tubular work 2, the liquid supply source 7 supplies the pressurized liquid L (water or oil). ) Is supplied to the hollow chamber 21 of the tubular workpiece 2 through the hollow portion 52 of the regulating member 5 and the passage 35 of the pressure receiving body 3. With the hollow chamber 21 of the tubular workpiece 2 kept at the predetermined hydraulic pressure P in this manner, the tubular workpiece 2 is subjected to bending. At this time, the axial end portion 20 of the tubular work 2 is not drawn in the direction of the arrow X2 toward the central region of the tubular work 2 in the axial direction.
[0048]
In this respect, according to the present embodiment, the pressure receiving surface 34 of the pressure receiving body 3 receives the hydraulic pressure P in the hollow chamber 21 of the tubular workpiece 2 as in the first embodiment, so that it opposes the elastic force of the spring member 38. Then, the pressure receiving body 3 is urged toward the shaft tip 2e of the tubular workpiece 2 (in the direction of the arrow X1) to be displaced. As in the first embodiment, the small diameter portion 32 of the pressure receiving body 3 is displaced along the guide wall surface 53 a of the guide hole 53. Here, since the outer inclined surface 33 of the pressure receiver 3 is engaged with the inner inclined surface 41 of the work restraining member 4D, the pressure receiving surface 34 of the pressure receiver 3 receives the hydraulic pressure P of the hollow chamber 21 of the tubular workpiece 2. The direction of the received pressure is changed as a force for urging the constraining surface 42 of the work restricting body 4D in the radially outward direction of the tubular work 2 (the direction of the arrow Y1) by the so-called wedge principle. For this reason, the constraint surface 42 of the workpiece constraint body 4D presses the inner wall surface 20i of the shaft end 20 of the tubular workpiece 2 along the radial direction (the direction of the arrow Y1) of the tubular workpiece 2.
[0049]
As a result, the restraining property of the shaft end 20 of the tubular work 2 is enhanced, and excessive pulling of the shaft end 20 of the tubular work 2 in the direction of arrow X2 is suppressed. Even if the drawing-in occurs, even if the drawing-in occurs, it can be suppressed to a constant amount, so that the variation in the drawing-in amount can be suppressed, and the tubular workpiece 2 can be formed favorably.
[0050]
The more the liquid in the hollow chamber 21 of the tubular workpiece 2 increases, the more the pressure received on the pressure receiving surface 34 of the pressure receiving body 3 increases, so that the constraint on the shaft end 20 of the tubular workpiece 2 is enhanced.
[0051]
According to the present embodiment, since the work restraint 4D is formed using rubber or resin as a base material, when the inner inclined surface 41 of the work restraint 4D is pressed by the outer inclined surface 33 of the pressure receiving body 3, Since the work restraint 4D can be elastically deformed in a radially outward direction (direction of arrow Y1), at least one of the first seal member 61 and the second seal member 62 used in the first embodiment may be omitted.
[0052]
(Seventh embodiment)
FIG. 10 shows a seventh embodiment of the present invention. This embodiment has basically the same configuration as the above-described first embodiment, and basically has the same operation and effect. Hereinafter, a description will be given focusing on portions different from the first embodiment. This embodiment is applied to hydroform molding in which the peripheral wall 2a of the tubular work 2 is expanded and formed by the liquid of the pressure liquid L supplied to the hollow chamber 21 of the tubular work 2. The first mold 11E has a first mold surface 15E to which the peripheral wall 2a of the expanded tubular work 2 is in close contact, and the second molding die 12E is a second mold surface to which the peripheral wall 2a of the expandable tubular work 2 is in close contact. It has a type 2 surface 16E.
[0053]
Also in this embodiment, when the pressure receiving body 3E and the work restraining body 4E are attached to the inner wall surface 20i side of the shaft end portion 20 in the axial direction of the tubular work 2, the liquid supply source 7 supplies the pressurized liquid L (water or oil). ) Is supplied to the hollow chamber 21 of the tubular workpiece 2 through the cavity 52 of the regulating member 5 and the passage 35 of the pressure receiving body 3E. By increasing the hydraulic pressure P in the hollow chamber 21 of the tubular workpiece 2 in this way, the peripheral wall 2a of the tubular workpiece 2 is plastically deformed in the expanding direction (the direction of the arrow Y3), and the first mold surface 15E and the second mold Hydroform molding is performed by closely contacting the surface 16E. At this time, the regulating member 5 is moved toward the intermediate region of the tubular workpiece 2 in the axial direction (in the direction of the arrow X2), and hydroforming is performed while pressing the shaft end 20 of the tubular workpiece 2 in the same direction.
[0054]
Also in the present embodiment, since the pressure receiving surface 34 of the pressure receiving body 3E receives the hydraulic pressure P of the hollow chamber 21 of the tubular workpiece 2, the pressure receiving body 3E is pressed against the elastic force of the spring member 38. It is urged toward the shaft tip 2e (in the direction of arrow X1) and displaced. The small diameter portion 32 of the pressure receiving body 3E is displaced along the guide wall surface 53a of the guide hole 53. Here, since the outer inclined surface 33 of the pressure receiving member 3E is engaged with the inner inclined surface 41 of the work restraining member 4E, the pressure receiving surface 34 of the pressure receiving member 3E receives the hydraulic pressure P of the hollow chamber 21 of the tubular workpiece 2. The direction of the received pressure is changed as a force for urging the restraining surface 42 of the work restraining body 4E in a radially outward direction of the tubular work 2 (direction of the arrow Y1) by a so-called wedge principle. Therefore, the restraint surface 42 of the work restraint 4E is pressed in the radial direction of the tubular work 2, that is, in the direction of arrow Y1. As a result, the restraining property of the shaft end 20 of the tubular work 2 is enhanced, and excessive pulling of the shaft end 20 of the tubular work 2 in the direction of arrow X2 is suppressed. As the liquid in the hollow chamber 21 of the tubular workpiece 2 increases, the pressure received on the pressure receiving surface 34 of the pressure receiving body 3E increases, so that the constraint on the shaft end 20 of the tubular workpiece 2 is enhanced.
[0055]
(Other)
The work restraint 4 is divided into six pieces in the circumferential direction of the work restraint 4, but is not limited thereto, and the number of divisions is two, three, four, five, seven, eight, or It may be divided further. Although the divided body 46 according to the first embodiment is formed of a metal material or a ceramic material, it is not limited thereto, and may be formed of a hard rubber or a hard resin. In addition, the present invention is not limited to only the above-described embodiments, and can be implemented with appropriate modifications without departing from the gist.
[0056]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the shaft end of the tubular work from being excessively drawn toward the central region in the axial direction of the work during the hydroforming, and the drawing is performed. Provided is a hydraulic forming method capable of suppressing the variation of the drawing-in amount even if it occurs even if it occurs, suppressing the variation of the drawn-in amount, and favorably forming the tubular work, and a work terminal supporting structure used for the hydraulic forming. can do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a work terminal supporting structure used for hydroforming according to a first embodiment.
FIG. 2 is a side view of the pressure receiving member according to the first embodiment with a first seal member and a second seal member removed.
FIG. 3 is a front view of a work restraint body according to the first embodiment.
FIG. 4 is a cross-sectional view of the work restraint according to the first embodiment, as viewed from the direction of arrows along line IV-IV in FIG. 3;
FIG. 5 is a sectional view of a work restraint body according to a second embodiment.
FIG. 6 is a sectional view of a work restraint body according to a third embodiment.
FIG. 7A is a front view of a tubular workpiece according to the fourth embodiment, and FIG. 7B is a cross-sectional view showing a part of a work terminal supporting structure used for hydroforming according to the fourth embodiment. is there.
FIG. 8 is a front view of a tubular workpiece according to a fifth embodiment.
FIG. 9 is a cross-sectional view showing a work terminal supporting structure used for hydroforming according to a sixth embodiment.
FIG. 10 is a sectional view showing a work terminal support structure used for hydraulic forming according to a seventh embodiment.
FIG. 11 is a cross-sectional view showing a work terminal support structure used for hydroforming according to the related art.
FIG. 12 is a cross-sectional view showing a work terminal supporting structure used for hydroforming according to the related art.
[Explanation of symbols]
In the figure, 1 is a molding die, 2 is a tubular workpiece, 20 is a shaft end, 21 is a hollow chamber, 3 is a pressure receiving body (pressure receiving direction conversion transmitting means), 33 is an outer inclined surface, 34 is a pressure receiving surface, and 4 is a pressure receiving surface. Reference numeral 41 denotes an inner inclined surface, reference numeral 42 denotes a restricting surface, reference numeral 46 denotes a divided body, reference numeral 49 denotes a cord, reference numeral 5 denotes a regulating member, and reference numerals 64 and 64B denote engagement degree increasing portions.

Claims (8)

In a hydraulic forming method of forming the tubular work by applying a hydraulic pressure to the hollow chamber of the tubular work,
The tubular work has a pressure receiving surface facing the hollow chamber and a constraining surface facing the inner wall surface of the shaft end of the tubular work, and receives the pressure received by the pressure receiving surface in a radially outward direction of the tubular work. Using a pressure-receiving direction change transmission means that changes direction and transmits as a force along,
The receiving pressure direction change transmission means is disposed on the inner wall surface side of the shaft end of the tubular work,
During the forming of the tubular work, the liquid pressure in the hollow chamber of the tubular work is received by the pressure receiving surface of the pressure receiving direction change transmission unit, and the pressure received by the pressure receiving surface is reduced by the diameter of the tubular work. The direction is changed as a force along the outward direction, and the constraining surface of the pressure receiving direction change transmission unit is pressed against the inner wall surface of the shaft end of the tubular work along the radially outward direction of the tubular work. A hydraulic forming method characterized by increasing the restraint of the shaft end of the tubular workpiece. A pressure-receiving surface that is disposed on the inner wall surface side of the shaft end of the tubular work and receives the hydraulic pressure in the hollow chamber of the tubular work, and an outer side that has a taper whose diameter decreases toward the axial end in the axial direction of the tubular work. A pressure receiving body having an inclined surface,
An inner side which is disposed on the inner peripheral surface side of the shaft end of the tubular work, engages with the outer inclined surface of the pressure receiving body, and has a taper whose diameter decreases toward an axial front end of the tubular work in the axial direction. A work restraint body having an inclined surface and a restraint surface that faces the inner wall surface of the shaft end of the tubular work and presses and restrains the inner wall surface of the shaft end of the tubular work in a radially outward direction. A work terminal supporting structure used for hydraulic forming, comprising: 3. The work terminal supporting structure used in hydraulic forming according to claim 2, further comprising a regulating member that regulates movement of the work restricting body toward a shaft tip of the tubular work. 4. The pressure receiving body according to claim 2, wherein the outer inclined surface of the pressure receiving member is formed in a circumferential direction around an axis of the pressure receiving member, and the inner inclined surface of the work restraining member is formed of the work restraining member. A work terminal supporting structure used for hydraulic forming, which is formed in a circumferential direction around an axis. In any one of Claims 2 to 4, the work restricting body is formed of a plurality of divided bodies in a circumferential direction of the work restricting body,
A work terminal supporting structure used for hydraulic forming, wherein each of the divided bodies has the inner inclined surface and the constraint surface, respectively. 6. The hydraulic forming method according to claim 5, wherein a stretchable cord is attached to each of the divided bodies of the work restricting body, and the divided bodies are connected to each other by the cord. Work terminal support structure. In any one of Claims 2 to 6, the restraining surface of the work restraining body includes an engagement degree increasing portion that increases engagement with an inner wall surface of the shaft end of the tubular work. A work terminal support structure for use in hydraulic forming, comprising: The work restraint according to any one of claims 2 to 7, wherein the work restraint is formed using any one of a metal material, a ceramic material, and an elastically deformable material as a base material. Work terminal support structure used for hydraulic forming.

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