JP2003103314A - Method and apparatus for manufacturing metal bent pipe having bulge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a metal bent pipe having a bulge capable of making manufacturing costs inexpensive. SOLUTION: The method for manufacturing the metal bent pipe having a bulge is characterized in that the method is a manufacturing method of a metal bent pipe 1 where the pipe is curved in the intermediate portion of the longitudinal direction and the bulge 1d is formed on the curved portion. A hydroforming die 10 having a restraining portion 13, composed of an upper and lower die 11, 12, to restrain pipe expansion in both end portions of a stock pipe P made of a metal and a cavity 14 to form the bulge portion 1d is prepared. When the die clamping force of both vertical dies 11, 12 of the hydroforming die 10 is performed, the stock pipe P is bent and a fluid pressure is introduced into the stock pipe P to form the bulge 1d under this condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a bent metal pipe having a bent portion at a middle portion in the longitudinal direction and a bulge portion formed at the bent portion.

[0002]

2. Description of the Related Art Conventionally, a bent metal tube with a bulged portion of this type has been manufactured by bending a circular metal tube made of metal and then forming a bulged portion in the bent portion by hydroforming. .

[0003]

However, in the conventional method, it is necessary to perform the bending process and the hydroforming by using separate dedicated apparatuses, so that the number of manufacturing steps increases and the equipment cost increases, As a result, there is a problem that the manufacturing cost becomes high.

It is an object of the present invention to provide a method and apparatus for manufacturing a metal tube with a bulging portion, which can solve the above problems and reduce the manufacturing cost.

[0005]

In the method for manufacturing a metal bent pipe with a bulging portion according to the invention of claim 1, the bent portion is bent at an intermediate portion in the longitudinal direction, and the bulged portion is formed in this bent portion. A method of manufacturing a bent metal pipe,
A hydroforming mold having a plurality of split molds and having a restraining portion for restraining expansion of both ends of the metal raw pipe and a bulging portion forming cavity portion forming a bulging portion is prepared. It is characterized in that the blank pipe is bent when the forming mold is clamped, and in this state, a fluid pressure is introduced into the blank pipe to form a bulging portion.

In the first aspect of the invention, the metal raw pipe includes a steel pipe, an aluminum pipe (including an aluminum alloy pipe), a titanium pipe (including a titanium alloy pipe), and a magnesium pipe (a magnesium alloy pipe). ), A straight pipe such as a copper pipe (including a copper alloy pipe) is used.

According to a second aspect of the present invention, there is provided a method for manufacturing a bent metal tube having a bulging portion, wherein in the first aspect of the invention, a hydroforming die including two split dies is used, and the metal base pipe is placed in one direction. Only bend to.

According to a third aspect of the present invention, there is provided a method for manufacturing a bent metal tube having a bulging portion, according to the second aspect of the invention, in which the hydroforming die is clamped before the die clamping is completed. Using a bending punch that is actuated by the movement of the element, the element tube is bent in a direction different from the bending direction when the hydroforming die is clamped.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a bent metal tube having a bulging portion, wherein the hydroforming die comprising three divided dies is used in the second aspect.
The split pipe is bent in the first direction by one split mold, and the split pipe is bent in the second direction different from the first direction by the remaining split mold.

According to a fifth aspect of the present invention, there is provided a method for producing a bent metal pipe having a bulging portion, according to any one of the first to fourth aspects, in which the hydroforming die is clamped in advance in the raw pipe before the die is clamped. This is to fill the liquid and close the openings at both ends of the base pipe to increase the liquid pressure in the base pipe after the mold is clamped.

According to a sixth aspect of the present invention, there is provided a method for manufacturing a bent metal pipe having a bulging portion, wherein the bent pipe is bent in a crank shape in any one of the first to fifth aspects. It is intended to manufacture a pipe in which a connecting portion for connecting the tips of the arm portions is bulged to have an irregular cross section.

A bent metal tube with a bulging portion according to the invention of claim 7 is manufactured by the method according to any one of claims 1 to 6.

According to an eighth aspect of the present invention, there is provided an apparatus for manufacturing a bent metal pipe having a bulged portion, which manufactures a bent metal tube which is bent at an intermediate portion in the longitudinal direction and has a bulged portion at the bent portion. And a cavity for forming a bulge forming a bulge and a bulge forming cavity formed of two split dies. A bending punch portion is provided on one of the split dies and a bending die portion is provided on the other of the split dies, and the expansion die is provided between the bending punch portion and the bending die portion. The present invention is characterized in that a cavity portion for forming the projecting portion is provided.

According to a ninth aspect of the present invention, there is provided an apparatus for manufacturing a metal bent pipe with a bulging portion, wherein the bending punch and the split die for clamping the hydroforming die are moved in the eighth aspect. And a transmission means for moving the forming punch in a direction different from the moving direction of the split die, and the bending punch is moved to the raw pipe side by the transmission means before the die clamping of the hydroforming die is completed. As a result, the material pipe is bent in a direction different from the bending direction of the hydroforming die when it is clamped, and then returned to a position where it does not interfere with the hydroforming die.

According to a tenth aspect of the present invention, there is provided an apparatus for manufacturing a bent metal tube having a bulged portion, which manufactures a bent metal tube which is bent at an intermediate portion in the longitudinal direction and has a bulged portion at the bent portion. Which is a device for
A hydroforming mold which is composed of two split molds and has a restraint portion that restrains expansion of both ends of the metal blank tube and a bulge portion forming cavity portion that forms a bulge portion; 1st to either of 2nd division type
Is provided with a first bending punch portion for bending the tube in the direction of, and the other is provided with a first bending die portion that cooperates with the first bending punch portion. The mold is provided with a second bending punch part for bending the raw pipe in a second direction different from the first direction, and the first and the second holding punches hold the raw pipe in a bent state in the first direction. Second
The split mold is provided with a second bending die portion that cooperates with the second bending punch portion, and the expansion die is provided between the first and second bending punch portions and the first and second bending die portions. The present invention is characterized in that a cavity portion for forming the projecting portion is provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 This embodiment is shown in FIGS. 1 to 4. In the description of this embodiment, the upper and lower sides and the left and right sides in FIG. 2 are referred to as the upper and lower sides and the left and right sides, respectively.

A bent metal tube with a bulging portion manufactured by the method of this embodiment is shown in FIG. 4 (c).

In FIG. 4 (c), the bent metal pipe (1) with a bulging portion is in the shape of a crank, and has a straight tubular portion (1a) having a circular cross section with a predetermined length at both ends, and a straight tubular portion. (1a) and two arm portions (1b) that are inclined downward toward the central portion in the longitudinal direction of the curved metal pipe (1) and a connecting portion that connects the tips of these arm portions (1b) It consists of (1c). The two arm portions (1b) and the connecting portion (1c) of the bent metal tube (1) with a bulging portion are bulged so that the cross-sectional shape thereof is a vertically elongated circular shape that is long in the vertical direction. This bulge is indicated by (1d). Two straight tubular parts (1a),
The two arm portions (1b) and the connecting portion (1c) are located on the same straight line when seen in a plane. Further, the straight tubular portion (1a) of both arm portions (1b) in the metal bent pipe (1) with a bulging portion
From the side end portion to the central portion of the length of the connecting portion (1c), the vertical length of the cross-sectional shape is gradually increased.

1 to 3, the apparatus for manufacturing a bent metal pipe (1) with a bulging portion is composed of two upper and lower split molds (11) and (12), and both end portions of the metal pipe (P). Restraint part to restrain
(13) and bulge forming cavity forming bulge (14)
And a hydroforming mold (10) having

A bending punch part (15) is integrally formed on the lower surface of the upper split mold (11) excluding the peripheral edge so as to project downward, and a bending punch part on the lower surface of the upper split mold (11) is formed.
Upper restraint portions (20) for preventing upward bulging of the raw pipe (P) are provided on both left and right sides of (15). From the upper restraint portion (20) on the lower surface of the upper split mold (11) to the left and right side surfaces and the lower surface of the bending punch portion (15), there is a concave groove (16) into which the upper half of the raw pipe (P) is fitted. , Is formed continuously so as to extend in the left-right direction and open downward. The groove (16) has a semicircular cross section, and the upper half of the hollow shell (P) is fitted therein.

On the upper surface of the lower split mold (12) excluding the peripheral portion, a bending die part (17) is formed which is recessed downward and fits the bending punch part (15) of the upper split mold (11). On the upper surface of the lower split mold (12), lower restraint portions (21) for preventing downward expansion of the raw pipe (P) are provided on both left and right sides of the bending die portion (17). Then, the upper restraint (2) of the upper split type (12)
(0) and the lower restraint (21) of the lower split type (12), the tube (P)
Restraint portions (13) for restraining the tube expansion at both ends of the are formed. From the lower restraint part (21) to the left and right side surfaces and the bottom surface of the bending die part (17), the concave groove (18) into which the lower half part of the bare pipe (P) is fitted extends horizontally and opens upward. Are formed continuously. A portion of the concave groove (18) existing in the lower restraining portion (21) has a semicircular cross section, and the lower half portion of the hollow shell (P) is fitted therein. The portion existing from both side surfaces to the bottom surface of the bending die portion (17) in the concave groove (18) of the lower split mold (12) is from the upper end portion of the portion formed on both side surfaces of the bending die portion (17). The bulging portion forming cavity portion (14) is formed by gradually increasing the depth toward the central portion of the length of the portion formed on the bottom surface.

Next, a method for manufacturing a bent metal tube with a bulging portion using the above-described manufacturing apparatus will be described.

First, the upper and lower split molds (11) and (12) are separated from each other, and the hydroforming mold (10) is opened.
After fitting both end portions of (P) into the portion existing in the lower restraining portion (21) in the concave groove (18) of the lower split mold (12) (Figs. 2 to 4).
(A)), for example, the upper split mold (11) is lowered to bring the upper and lower split molds (11) and (12) close to each other to clamp the hydroforming mold (10). Then, the bending punch part (15) of the upper split mold (11) and the bending die part (17) of the lower split mold (12) work to bend the raw pipe (P) into a crank shape (Fig. 2 to Fig. 2). (See FIG. 4 (b)). Further, both ends of the raw pipe (P) are constrained by the constraining portions (13). Then, the both ends of the raw pipe (P) are closed with a seal fitting (19) having a fluid introduction through hole (19a), and the raw pipe is passed through the fluid introduction through hole (19a).
By introducing a fluid into (P) and applying internal pressure, the sealing pipe (19) is used to bend the raw pipe (P) by a hydroforming method that compresses the raw pipe (P) in the longitudinal direction. The bulging portion forming cavity portion (14), that is, the inner peripheral surface of the portion formed on the side surface and the bottom surface of the bending die portion (17) in the concave groove (18) of the lower split mold (12). It is swollen so as to follow (see (c) of FIGS. 2 to 4). The air existing in the raw pipe (P) is discharged from an air vent hole (not shown) formed in one of the seal fittings (19). In this way, the bent metal tube (1) with a bulged portion is manufactured.

Next, a specific example of a method of manufacturing the bent metal tube (1) with a bulge will be described.

An extruded tube made of AA6063 alloy and having an outer diameter of 40 mm, a wall thickness of 2 mm and a length of 600 mm was used as a raw tube (P). The height of the bending punch (15) of the upper split type (11) is 40
mm, and the depth of the bending die part (17) of the lower split mold (12) was set to 40 mm. The bottom surface of the bending die part (17) in the concave groove (18) of the lower split mold (12) has the deepest circumference, and the bottom surface of the bending punch part (15) of the upper split mold (11) The total length of the groove (16) and the circumferential length of the concave groove (16) was made equal to the circumferential length of a circle having a diameter of 48 mm. Further, the length of the portion of the recessed grooves 16 and 18 existing in the restraining portion 13 is set to 70 mm.

Then, the upper and lower split molds (11) and (12) are separated from each other and the hydroforming mold (10) is opened,
After fitting both ends of (P) into the part existing in the lower restraint part (21) in the concave groove (18) of the lower split mold (12), the upper split mold (1
The hydroforming die (10) was clamped by lowering 1) to bring the upper and lower split dies (11) and (12) close to each other. Next, the both ends of the raw pipe (P) are closed with seal fittings (19), a fluid is introduced into the raw pipe (P) through the fluid introduction through hole (19a) to apply an internal pressure of 30 MPa, and the seal fitting Using (19), the blank tube (P) was compressed in the length direction. As a result, no damage or the like was found on the peripheral wall of the produced pipe (1).

Embodiment 2 This embodiment is shown in FIGS. In addition,
In the description of this embodiment, the upper and lower sides and the left and right sides in FIG. 6 are referred to as the upper and lower sides and the left and right sides, and the left side is referred to as the front side and the right side is referred to as the rear side in FIG.

A metal bent tube with a bulge manufactured according to this embodiment is shown in FIG.

In FIG. 5, the bent metal pipe (3
(0) is a crank shape and has a straight tubular portion (30a) with a circular cross section having a predetermined length at both ends, and a long side of the metal bent pipe (30) connected to the straight tubular portions (30a) and downward. Two arm parts (30b) inclined toward the center and in the forward direction
And a connecting portion (30c) for connecting the tips of these arm portions (30b). Metal bend pipe with bulge (3
Two arm parts (30b) and connecting parts (30c) in (0)
Is bulged so that the cross-sectional shape is a vertically elongated circular shape that is long in the vertical direction. This bulge is shown by (30d). Both arms (30b) in the bent metal tube (30) with bulge
From the end of the straight tubular portion (30a) side to the end of the connecting portion (30c), the vertical length of the cross-sectional shape is gradually increased. Further, the two straight tubular portions (30a) are located on the same straight line when seen in a plane.

6 to 15, the apparatus for manufacturing the bent metal pipe (30) with a bulging portion is composed of two upper and lower split molds (31) (32), and both end portions of the metal raw pipe (P). Restraint part to restrain
(33) and bulge forming cavity forming bulge (34)
And a bending punch (36) arranged at the rear of the hydroforming die.

Bending punches (37) are integrally formed on the lower surface of the upper split mold (31) excluding the left and right ends so as to project downward. A restraint member (38) that is moved up and down with respect to the upper split mold (31) by an unillustrated hydraulic cylinder or the like and that prevents the raw pipe (P) from bulging upward is provided. On the left and right side surfaces and the lower surface of the bending punch part (37) of the upper split mold (31), there are recessed grooves (39) into which the upper half part of the raw pipe (P) is fitted and which extend in the left-right direction and open downward. Are formed continuously. Groove
The portions of the bending punch portion (37) on the left and right sides of the bending punch portion (37) are inclined rearward toward the upper side. This inclined portion is indicated by (39a), and the bottom portion existing on the bottom surface of the concave groove (39) is indicated by (39b) (see FIG. 8). The groove (39) has a semicircular cross section, and the upper half of the hollow shell (P) is fitted therein. On the lower surface of the restraint member (38), extend in the left-right direction and
A groove (40) into which the upper half of (P) fits is formed.

Bending die parts (41) are formed in the upper surface of the lower split mold (32) excluding the left and right ends, and are recessed downward and the bending punch parts (37) of the upper split mold (31) are fitted. On the left and right sides of the bending die part (41) of the lower split mold (32), lower restraining portions (42) for preventing downward expansion of the raw pipe (P) are provided. The restraint member (38) and the lower restraint portion (42) restrain the expansion of both ends of the raw pipe (P) (33).
Are formed. On the upper surface of the lower restraining portion (42) of the lower split mold (32), a concave groove (44) into which the lower half portion of the raw pipe (P) is fitted is formed so as to extend in the left-right direction. On the left and right side surfaces and bottom surface of the bending die part (41) of the lower split mold (32),
The concave groove (43) into which the lower half portion of (P) is fitted is formed continuously so as to open upward and extend in the left-right direction.
The left and right ends of the groove (43) are connected to the groove (44) of the lower restraint portion (42). Also, the bending die part (4
The parts on both left and right sides of 1) are the concave grooves of the upper split type (31).
It is inclined rearward toward the upper side so as to correspond to the inclined portion (39a) of (39). This inclined portion is indicated by (43a), and the bottom portion existing on the bottom surface of the bending die portion (41) is
This is indicated by (43b). The depth of the bottom portion of the concave groove (43) is deeper than the radius of the raw tube (P). The depth of the inclined portion (43a) of the concave groove (43) is equal to that of the concave groove (44) of the lower restraining portion (42) at the upper end, and is gradually deeper toward the lower end. In the part, it is equal to the depth of the bottom part (43b). Then, the inclined portion (43a) and the bottom portion (43) of the concave groove (43)
The b) forms the bulging portion forming cavity portion (34).

A horizontal plate (45) is fixed to the upper end surface of the upper split mold (31) so as to project rearward, and a bending punch (36) is provided at the rear end of the horizontal plate (45) in the left-right direction. ), A downward protrusion (46) is integrally formed.
The front surface of the downward protrusion (46) is a vertical surface. A bending punch (36) is arranged on the front side of the downward protrusion (46) and at a height position corresponding to the lower restraining portion (42) of the lower split mold (32).
The bending punch (36) is a base to which the lower split mold (32) is fixed.
A support (48) provided upright on (47) is provided at the upper end of the support (48) so as to be movable in the front-rear direction and is always biased rearward by a biasing means (not shown). On the front end face of the bending punch (36),
A concave groove (49) having a semicircular cross section into which the raw pipe (P) is fitted is formed.

Bending punch (36) and upper mold lower projection (46)
A direct-acting cam device for moving the bending punch (36) in the front-back direction is provided between and. The cam device includes a cam (50) integrally formed on the front surface of the lower protruding portion (46) and protruding forward so as to have a chevron shape when viewed from the side, and a bending punch.
It consists of a cam follower (51) attached to the rear end of (36). The contour of the cam (50) is composed of a first inclined portion (50a) that is inclined forward and upward, a vertical portion (50b) that extends upwardly from the upper end of the first inclined portion (50a), and a vertical portion. A second inclined portion (50c) which is continuous with the upper end of (50b) and is inclined rearward toward the upper side.
Consists of. The protruding height of the cam (50) from the lower protruding portion (46) to the front is such that when the cam follower (51) reaches the vertical portion (50b), the bending punch (36) moves the pipe (P) forward. It has a height that allows it to be bent. Also, the vertical width of the cam (50) and the rearward protruding length of the horizontal plate (45) are
When the cam follower (51) reaches the rear end of the second inclined part (50c), the front end of the bending punch (36) is divided into upper and lower split types (31) (32).
The width and length are set so that it comes closer to the rear than that.
Also, the vertical length of the downward protrusion (46) should be such that the bending punch (36) does not hit the horizontal plate (45) until the upper and lower split dies (31) (32) are clamped. It has a long length.

Next, a method of manufacturing the bent metal tube (30) with a bulging portion using the above-described manufacturing apparatus will be described.

First, the upper and lower split molds (31) and (32) are separated from each other and the hydroforming mold is opened, and the raw pipe (P)
After fitting both ends of the above into the concave groove (44) of the lower restraining portion (42) of the lower split mold (32) (see FIGS. 6 (a) and 8), the restraining member (38)
Lowering both ends of the tube (P) by
Restrain by 3). Then, when the upper split mold (31) is lowered, the cam follower (51) first moves the first inclined portion (50) of the cam (50).
a) (see FIG. 11), the cam follower (51) rolls along the first inclined part (50a) by the further lowering of the upper split mold (31), and the bending punch (36) moves. It moves forward against the biasing force of the biasing means (see FIG. 6 (b)). Cam Follower (5
When 1) reaches the vertical portion (50b), the bending punch (36) reaches the forward position, whereby the raw pipe (P) is bent forward in a crank shape (see FIG. 12). Then, when the upper split mold (31) is further lowered, the bending punch (36) is biased rearward by the biasing means, so that the cam follower (51) rolls along the second inclined portion (50c). Then, the bending punch (36) moves rearward, the cam follower (51) reaches the rear end of the second inclined portion (50c), and the bending punch (36) moves to the retracted position (Fig. 1).
3). When the blank tube (P) is bent by the bending punch (36), the clamping of the hydroforming die has not been completed. After the bending punch (36) moves to the retracted position, the upper split mold (31) is further lowered to complete the clamping of the hydroforming mold. Then, the bending punch part (37) of the upper split mold (31) and the lower split mold (32)
By the function of the bending die part (41) of
The arm portion (P1) of (P) and the connecting portion (P2) that connects the tips of these arm portions (P1) are bent downward (see FIGS. 7C and 14). At this time, both arm portions (P1) of the blank pipe (P) are respectively formed by the inclined portion (39a) of the concave groove (39) of the upper split mold (31) and the concave groove (43) of the lower split mold (32). Inclined part (43
a) and the connecting part (P2) is the groove (3) of the upper split mold (31).
9) bottom part (39b) and bottom split mold (32) groove (43) bottom part (43
b) fit inside Then, the both ends opening of the raw pipe (P) is closed by a seal fitting (19) having a through hole for fluid introduction (19a),
Hydroforming method in which the fluid is introduced into the raw pipe (P) through the fluid introduction through hole (19a) to apply internal pressure, and the sealing pipe (19) is used to compress the raw pipe (P) in the longitudinal direction. The bent portion of the raw pipe (P) is made into a bulge forming cavity portion (34), that is, the concave groove (43) of the lower split mold (32).
The bending die portion (41) is bulged along the inner peripheral surface of the portion formed on the side surface and the bottom surface of the bending die portion (41) (see FIGS. 7D and 15). The air existing in the raw pipe (P) is discharged from an air vent hole (not shown) formed in one of the seal fittings (19). Thus, the bent metal tube (30) with a bulged portion is manufactured.

In the second embodiment, the bending punch is used.
The (36) is configured to move in the front-rear direction by a cam device including a cam (50) integrally provided on the upper split mold (31) and a cam follower (51) provided on the bending punch (36). However, instead of this, the bending punch (36) may be moved in the front-rear direction by a hydraulic cylinder or the like.

Embodiment 3 This embodiment is shown in FIGS. 16 to 22. In the description of this embodiment, the upper and lower sides of FIG. 16 are referred to as the upper and lower sides, and the left and right sides are referred to as the left and right sides of FIG.

The metal bent pipe (30) with a bulging portion manufactured according to this embodiment has the same shape as that manufactured according to the second embodiment.

16 to 22, the apparatus for manufacturing the bent metal pipe (30) with a bulging part is composed of three upper and lower split molds (60) (61) (62), and is made of metal. A hydroforming die having a restraining portion (63) for restraining both ends of (P) and a bulging portion forming cavity portion (64) forming a bulging portion is provided.

A first bending punch portion (65) for bending the raw pipe (P) downward is integrally formed on the lower surface of the upper split mold (60) excluding the left and right ends. Upper restraint portions (66) for preventing upward expansion of the raw pipe (P) are provided on both left and right sides of the first bending punch portion (65). Upper split type
Downward protruding portions (6) extending in the left-right direction are formed on the left and right side surfaces and the front side portion of the lower surface of the first bending punch portion (65) of the (60).
7) (68) is formed continuously and integrally. Each downward protrusion
The connecting portions of the rear surfaces of (67) and (68) with the left and right side surfaces and the lower surface of the first bending punch portion (65) are rounded. First
Lower protrusion (68) formed on the lower surface of the bending punch (65)
Has a projection height equal to the radius of the raw pipe (P), and the curvature of the connecting portion between the rear surface of the downward projection (68) and the lower surface of the first bending punch (65) is the outer peripheral surface of the raw pipe (P). Is equal to the curvature of.
The thickness of the downward protrusions (67) formed on the left and right side surfaces of the first bending punch (65) in the front-rear direction is determined by the first bending punch (6).
5) The thickness gradually increases outward in the left-right direction from the end portion on the lower projection (67) side formed on the lower surface.

On the front side of the lower surface of the upper restraining portion (66) of the upper split mold (60), a downward projecting portion (69) extending in the left-right direction is integrally formed. The downward projecting portion (69) is integrally connected to the downward projecting portions (67) formed on the left and right side surfaces of the first bending punch portion (65). The protruding height of the downward protruding part (69) is the tube (P)
Is equal to the radius of the
9) The connecting portion between the rear surface and the lower surface of the upper restraint portion (66) has a rounded shape, and the curvature of this rounded portion is equal to the curvature of the outer peripheral surface of the shell (P). The thickness of the downward protrusion (69) formed in the upper restraining portion (66) in the front-rear direction is the thickness of the downward protrusion (68) formed in the lower surface of the first bending punch portion (65) in the front-rear direction. The thickness in the front-rear direction of the downward protruding portions (67) formed on the left and right side surfaces of the first bending punch portion (65) is
It gradually becomes thinner from the outer end in the left-right direction toward the inner end, and the lower protrusion (67) is a lower protrusion at the outer end in the left-right direction.
It is connected to (69) and is a downward protrusion (68) at the inner end in the left-right direction.
It is connected to.

A first bending die portion (wherein the first bending punch portion (65) of the upper split die (60) fits in a portion of the upper surface of the lower split die (61) excluding both left and right ends) 70) is formed, and lower restraint portions (71) that prevent downward expansion of the raw pipe (P) are formed on both left and right sides of the first bending die portion (70) in the lower split mold (61). Has been done. On the bottom surface of the first bending die (70) of the lower split mold (61) and the front parts of the left and right side surfaces,
Upper protruding portions (72) and (73) extending in the left-right direction are integrally formed continuously. These upward protrusions (72) (73)
The connecting portions of the rear surface, the bottom surface of the first bending die portion (70), and the left and right side surfaces are rounded.

An upper projecting portion (74) extending in the left-right direction is integrally formed on the front portion of the upper surface of the lower restraining portion (71) of the lower split mold (61). The upper protruding portion (74) is integrally connected to the upper protruding portion (73) of the first bending die portion (70). Also,
The protrusion height of the upper protrusion (74) is equal to the radius of the raw pipe (P), and the rear surface of the upper protrusion (74) and the lower restraint
(71) The connecting portion with the upper surface is formed into a rounded shape, and the curvature of this rounded portion is equal to the curvature of the outer peripheral surface of the base pipe (P). Upper protrusion (74) formed on the lower restraint (71)
Is thicker than the thickness in the front-rear direction of the upward protrusion (72) formed on the bottom surface of the first bending die part (70), and is on the left and right sides of the first bending die part (70). The thickness of the upper protrusion (73) formed on the surface in the front-rear direction is gradually reduced from the outer end in the left-right direction toward the inner end.
The (73) is connected to the upper protrusion (74) at the outer end in the left-right direction and is connected to the upper protrusion (72) at the inner end in the left-right direction.

By the portion existing in front of the lower restraining portion (71) in the gap between the upper and lower split type first bending punch portions (65) and the first bending die portions (70) which are combined with each other, A second bending die part (75) for bending the pipe (P) forward is configured.

The rear split mold (62) is arranged behind the upper and lower split molds (60) (61) so as to move in the front-back direction. 1st bending punch (6
It is designed to be inserted between the bottom surface and the left and right side surfaces of 5) and the bottom surface and the left and right side surfaces of the first bending die part (70) of the lower split mold (61). The rear split mold (62) is inserted between the lower surface of the first bending punch part (65) of the upper split mold (60) and the bottom surface of the first bending die part (70) of the lower split mold (61). Central horizontal section (62
a) and the left and right ends of the horizontal portion (62a) and inclined upward in the left-right direction, and at the left and right side surfaces and the lower side of the first bending punch portion (65) of the upper split mold (60). The first part of the split mold (61) has a sloped part (62b) which is inserted between the left and right side surfaces of the first bending die part (70) and the outer end of the sloped part (62b) in the left-right direction. It is provided with both end horizontal portions (62c) which enter between the restraining portions (66) and (71) of the 60 (61). Both slopes (62
The front end faces of b) are inclined rearward outward in the left-right direction. Further, the thickness of both inclined portions (62b) in the up-down direction gradually decreases from the outer end in the left-right direction toward the inner end. A concave groove (76) into which the latter half of the plain tube (P) is fitted is opened forward along the entire height of the front surface of the central horizontal portion (62a), both inclined portions (62b) and both end horizontal portions (62c). Further, they are continuously formed so as to be continuous with each other. Rear split type (6
A portion existing in front of the horizontal portions (62c) at both ends of 2) is a second bending punch portion (77) for bending the raw pipe (P) forward.

When the hydroforming die consisting of the three split molds (60) (61) (62) is clamped, the lower protruding portion (66) of the upper restraining part (66) of the upper split mold (60) is 69), the upper projecting portion (74) of the lower restraining portion (71) of the lower split mold (61), and the horizontal portions (62c) at both ends of the rear split mold (62), so that both ends of the raw pipe (P) are A restraint portion (63) for restraining the expansion of the pipe is configured. When clamping the hydroforming die consisting of three split dies (60) (61) (62), the first bending punch part of the upper split die (60)
Lower protrusions (67) (68) in (65), upper protrusions (72) (73) in the first bending die part (70) of the lower split mold (61),
The second bending punch portion (77) of the rear split mold (62) constitutes a bulging portion forming cavity portion (64).

Next, a method for manufacturing a bent metal tube with a bulged portion using the above-described manufacturing apparatus will be described.

First, with the three split dies separated from each other and the hydroforming dies opened, both ends of the raw pipe (P) are placed above the lower restraint (71) of the lower split dies (61). Overhang (74)
Place it along the rear surface of the vehicle and temporarily secure it by appropriate means.
(See FIG. 16 (a) and FIG. 17). Then, upper split type (60)
Lower to match the upper and lower split molds. Then, the first bending punch part (65) of the upper split mold (60) and the first bending punch part (61) of the lower split mold (61).
The bending die part (70) bends the raw pipe (P) into a crank shape, and both ends of the raw pipe (P) are restrained by the upper and lower split dies (60) (61) (66) ( 71) (see FIG. 16 (b) and FIG. 20). Then, the rear split mold (62) is advanced to clamp the hydroforming mold. Then, the second bending punch part (77) of the rear split mold (62) and the second bending die part (7) formed between the upper and lower split molds (60, 61).
By the action of 5), both arm portions of the raw pipe (P) that are bent downward are bent forward. At this time, the plain tube (P)
Both arm portions and the connecting portion of the above enter into the bulging portion forming cavity portion (64) of the hydroforming mold. Also,
The straight portions on both ends of the raw pipe (P) are restrained by the hydroforming die restraining portion (63) so as not to expand (Fig. 1).
6 (c) and FIG. 21).

Then, the openings at both ends of the raw pipe (P) are closed by seal fittings (19) having a fluid introduction through hole (19a), and the fluid is introduced into the raw pipe (P) through the fluid introduction through hole (19a). Introduce a fluid to apply internal pressure and use the seal fitting (19) to
By the hydroforming method of compressing (P) in the longitudinal direction, the bent portion of the raw tube (P) is bulged along the bulging portion forming cavity (64) (Fig. 16 (d ) And FIG. 22). The air existing in the raw pipe (P) is discharged from an air vent hole (not shown) formed in one of the seal fittings (19). Thus, the bent metal tube (30) with a bulged portion is manufactured.

In the first to third embodiments described above, in the pre-bending step, the raw material pipe (P) is filled with the liquid and the openings at both ends thereof are closed, and thereafter the liquid pressure in the raw material pipe (P) is increased. You may do it. In this case, the risk of yielding when bending the raw pipe (P) due to clamping of the hydroforming mold is reduced.

[0053]

According to the inventions of claims 1 and 8, since a bent metal pipe having a bulging portion can be manufactured by bending and bulging using one hydroforming die, Compared to the above method, the man-hour is reduced and the facility cost is reduced. Therefore, the manufacturing cost of the bent metal tube with the bulging portion is reduced.

According to the third and tenth aspects of the present invention, it is possible to manufacture the metal bent pipe with the bulging portion bent in two different directions at a low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a hydroforming mold used in a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing the method of Embodiment 1 as viewed from the front, showing the order of steps.

3A is a sectional view taken along line XX of FIG. 2A, and FIG. 3B is FIG. 2B.
2 is a sectional view taken along line YY, and FIG. 2C is a sectional view taken along line ZZ in FIG.

FIG. 4 is a perspective view showing the method of Embodiment 1 in the order of steps with respect to only the tube.

5A and 5B show a metal bent pipe with a bulging part manufactured by the method of Embodiment 2 of the present invention, in which FIG. 5A is a plan view and FIG.
It is the sectional view on the AA line of (a).

FIG. 6 is a vertical cross-sectional view of the first half of the method of Embodiment 2 as viewed from the rear, showing the order of steps.

FIG. 7 is a vertical cross-sectional view showing the latter half of the method of Embodiment 2 as viewed from the rear, showing the order of steps.

FIG. 8 is an enlarged sectional view taken along line BB of FIG. 6 (a).

9 is a view taken along the line CC of FIG.

FIG. 10 is a view taken along the line DD of FIG.

11 is an enlarged cross-sectional view taken along the line EE of FIG. 6 (b).

FIG. 12 is a cross-sectional view corresponding to FIG. 11, showing a state in which the raw pipe is bent forward by a bending punch.

13 is a cross-sectional view corresponding to FIG. 11 showing a state where the bending punch is retracted.

14 is an enlarged sectional view taken along line FF of FIG. 7 (a).

FIG. 15 is an enlarged sectional view taken along line GG of FIG. 7 (d).

FIG. 16 is a vertical cross-sectional view showing the method of Embodiment 3 as viewed from the rear in the order of steps.

FIG. 17 (a) is an enlarged sectional view taken along line H1-H1 of FIG. 16 (a), (b).
FIG. 17 is an enlarged sectional view taken along line H2-H2 of FIG.

FIG. 18 is a view taken along the line I-I of FIG. 17 (a).

FIG. 19 is a view taken along the line JJ of FIG. 17 (b).

20 (a) is an enlarged cross-sectional view taken along the line K1-K1 of FIG. 16 (b), (b).
FIG. 17 is an enlarged sectional view taken along line K2-K2 of FIG.

FIG. 21 (a) is an enlarged sectional view taken along line L1-L1 of FIG. 16 (c), (b).
FIG. 17 is an enlarged sectional view taken along line L2-L2 of FIG.

22A is an enlarged cross-sectional view taken along the line M1-M1 of FIG. 16D, FIG.
FIG. 17 is an enlarged cross-sectional view taken along the line M2-M2 of FIG.

[Explanation of symbols]

(1) (30): Metal bent pipe with bulge (1a) (30a): Straight tubular part (1b) (30b): Arm part (1c) (30c): Connection part (1d) (30d): bulge (10): Hydroforming mold (11) (31) (60): Upper split type (12) (32) (61): Lower split type (13) (33) (63): Restraint (14) (34) (64): Cavity for forming bulge (15) (37): Bent punch (17) (41): Bending die (36): Bent punch (65): 1st bending punch (70): First bending die part (75): Second bending die part (77): Punch part for second bending (P): Metal tube

Continued front page    (72) Inventor Yasuhisa Hagiwara             Showaden 1-480 Inuzuka, Oyama City, Tochigi Prefecture             Koyama Works Co., Ltd. F-term (reference) 4E063 AA04 BA01 CA06

Claims (10)

[Claims] 1. A method for producing a bent metal pipe having a bent portion at a longitudinal middle portion and having a bulged portion formed in the bent portion, the method comprising a plurality of split molds, and A hydroforming die having a restraining portion for restraining expansion of both ends of a metal element pipe and a bulging portion forming cavity portion for forming a bulging portion is prepared. A method for producing a metal bent pipe with a bulging part, which comprises bending the pipe and introducing a fluid pressure into the raw pipe in this state to form a bulging part. 2. The method for producing a bent metal pipe with a bulged portion according to claim 1, wherein a metal forming pipe having two split molds is used and the metal base pipe is bent only in one direction. 3. Before the die clamping of the hydroforming die is completed, a blank punch is used by using a bending punch that is actuated by moving a split die for the die clamping. The method for manufacturing a metal bent pipe with a bulging portion according to claim 2, wherein the bent metal is bent in a direction different from the bending direction of the mold clamping. 4. A hydroforming die comprising three split dies is used, the raw pipe is bent in the first direction by the two split dies, and the raw pipe is placed in the first direction by the remaining one split dies. The method for manufacturing a metal bent pipe with a bulged portion according to claim 1, wherein the bent metal pipe is bent in a different second direction. 5. Prior to mold clamping of a hydroforming mold, liquid is preliminarily filled in the base pipe and both end openings of the base pipe are closed so that the liquid pressure in the base pipe is increased after the mold is clamped. The method for manufacturing a metal bent pipe with a bulging portion according to claim 1. 6. A pipe which is bent in a crank shape, and in which two arm portions and a connecting portion for connecting the tips of these arm portions are bulged to have an irregular cross-section. A method for producing a bent metal tube with a bulging part according to any one of 1. 7. A bent metal tube with a bulge manufactured by the method according to any one of claims 1 to 6. 8. An apparatus for manufacturing a metal bent pipe which is bent at an intermediate portion in the longitudinal direction and has a bulged portion formed on the bent portion, the apparatus comprising two split molds and made of metal. A hydroforming die having a restraining portion for restraining expansion of both ends of the raw pipe and a bulging portion forming cavity portion forming a bulging portion is provided, and one of the split dies for bending is provided. A punch portion is provided, and a bending die portion is provided on the other side, and a bulging portion forming cavity portion is provided between the bending punch portion and the bending die portion. Manufacturing equipment for bent metal pipes with bulge. 9. A bending punch and a transmission means for moving the bending punch in a direction different from the moving direction of the split die by moving the split die for clamping the hydroforming die are provided. Before the clamping of the draw forming mold is completed, the bending punch is moved to the base pipe side by the transmission means, so that the base pipe moves in a direction different from the bending direction of the hydro forming mold. 9. The apparatus for manufacturing a bent metal pipe with a bulging portion according to claim 8, which is configured to be bent and then returned to a position where it does not interfere with the hydroforming die. 10. An apparatus for manufacturing a bent metal tube, which is bent at an intermediate portion in the longitudinal direction and has a bulged portion at this bent portion, comprising three first to third split molds. And a hydroforming die having a restraint portion for restraining expansion of both ends of the metal blank and a bulge portion forming cavity portion forming a bulge portion,
One of the first and second split molds is provided with a first bending punch portion for bending the tube in the first direction, and the other one cooperates with the first bending punch portion. A first bending die portion is provided, and a second bending punch portion for bending the raw pipe in a second direction different from the first direction is provided in the third split mold, and the raw pipe is First
The first and second split dies, which are held in the state of being bent in the direction of, are provided with a second bending die part that cooperates with the second bending punch part, and the first and second bending punches are provided. An apparatus for manufacturing a bent metal pipe with a bulging portion, characterized in that a bulging portion forming cavity portion is provided between the portion and the first and second bending die portions.