JP2002035869A - Die for mechanical tube expander - Google Patents

Abstract

(57) [Problem] To provide a die for a mechanical pipe expander capable of pressing and correcting uncontacted portions generated on both sides of a bead such as a steel pipe at the time of straightening. A die (2) for correcting the periphery of a bead (1a) of a steel pipe (1) has a straightening body (1) extending in the die length direction on both sides of the bead.
A die for a mechanical pipe expander, which is provided so that it can protrude and retract in the escape groove. In addition, for the mechanical pipe expander as described above, the cam piston 13 engaging with the straightening body 22 extending in the die length direction is configured so that the straightening body 22 is protruded and retracted into the escape groove 3 by the pressure oil and the compression springs 15 and 16. Die.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die for a mechanical pipe expander for correcting the periphery of a bead portion of a steel pipe.

[0002]

2. Description of the Related Art Straight seam steel pipe is formed by molding a material.
After welding, it is straightened with a pipe expander. There are two types of pipe expanders: a hydraulic pipe expander that is used only for a thin plate and a mechanical pipe expander that can handle thin to thick pipes (see FIGS. 8 and 9). In this mechanical expansion machine, when expanding a pipe, the actual opening 5-7
As shown in FIG. 1 of No. 8328, a relief groove is formed in a part of the die so that a die to be used does not press a seam portion (bead portion) of the steel pipe.

[0003]

The relief groove width of the die must be wider than the bead width of the steel pipe. However, as shown in FIG. 10, when the width of the bead 1a of the steel pipe 1 is considerably smaller than the width of the clearance groove 3 of the die 3, the non-contact portion B where the steel pipe 1 and the die 2 do not contact each other on both sides of the bead 1a. However, there is a problem that the size is not corrected.

Generally, a tube having a small thickness is small, and a tube having a large thickness is large. Therefore, in order to solve the above problem, it is only necessary to rearrange the dies according to the thickness of the steel pipe.However, the rearrangement of the dies takes a long time, so that there is a problem that the production efficiency is reduced. In addition, it is necessary to have a large number of dies with relief grooves corresponding to the thickness range (bead width range) of steel pipes.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a die for a mechanical pipe expander capable of pressing an uncontacted portion formed on both sides of a bead such as a steel pipe at the time of straightening to straighten it. Aim.

[0006]

SUMMARY OF THE INVENTION The present invention provides the above object,
This is achieved by the following die. The die according to the first aspect of the present invention is a die for a mechanical expander in which a straightening body extending in a die length direction is provided on both sides of a bead so as to be able to protrude and retract into an escape groove.

According to a second aspect of the present invention, there is provided the die according to the first aspect, wherein the cam piston engaged with the straightening body extending in the length direction of the die is made to protrude and retract into the escape groove by the pressure oil and the compression spring. It is.

According to this die, when straightening a steel pipe having a large non-contact portion on both sides of the bead, pressure oil is supplied to the pressure oil chamber, the cam piston is advanced against the compression spring, and the straightening body is moved. Extrude to the upper surface of the escape groove against the compression spring. After that, the steel pipe is straightened by expanding the pipe expansion head. By doing so, the non-contact portions on both sides of the bead which could not be corrected conventionally can be corrected by the correction body. Here, the upper surface of the clearance groove refers to a surface extending from the outer surface of the die covering the opening of the clearance groove.

A third aspect of the present invention is the die according to the first aspect, wherein the straightening body, which extends in the length direction of the die and has ridges formed at both ends, is caused to protrude and retract into the escape groove by a hydraulic jack. .

According to this die, when straightening a steel pipe having a large non-contact portion on both sides of the bead, pressurized oil is supplied to each jack so that the top of the head of the straightening body is aligned with the upper surface of the relief groove. Then, the steel pipe is straightened by expanding the pipe expansion head. When the size of the non-contact portion on both sides of the bead is small, drain the pressure oil of each jack, set the top of the straightening body under the escape groove, and then expand the expansion head to straighten the steel pipe. Do. Thus, the correction body head does not press the bead during correction.

According to a fourth aspect of the present invention, in the first aspect, two wing plate members extending in the die length direction and having a pressing portion at an end thereof can be turned to the left and right of the plate member extending in the die length direction. And the biasing member is urged so as to be pushed out of the die by a compression spring so that the straightening member is formed in the escape groove.

According to this die, when straightening a steel pipe having a large non-contact portion on both sides of the bead (both the width and the height of the bead are small), the head of the plate is not pushed down by the bead, and the wing plate is not pressed down. The pressing portion is supported by the stepped portion of the engagement groove. Thus, when the expansion head is enlarged, the pressing portion of the blade plate body presses both sides of the bead to correct the steel pipe.

Further, when straightening a steel pipe having small non-contact portions on both sides of the bead (both the width and height of the bead),
In this case, when the tube expansion head is expanded, the head of the plate body is pushed down against the compression spring by the bead. This allows
Since the shaft is also lowered, the blade body turns around the shaft and contracts, and comes off the stepped portion and descends along the inclination of the inverted trapezoidal portion. That is, since the pressing portion of the wing plate body is lowered below the bottom surface of the clearance groove, the pressing portion does not push up the bead.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, the expansion head structure of the mechanical expansion machine to be used will be described. FIG. 8 is a longitudinal sectional view of a pipe expansion head of a mechanical pipe expander, and FIG.
It is -A sectional drawing. In the figure, reference numeral 2 denotes a die which is divided into a plurality in the circumferential direction and presses the inner wall of the steel pipe at the time of straightening. As shown in FIG. 9, among the plurality of dies 2, the dies 2 corresponding to the bead of the steel pipe,
An escape groove 3 is formed so as not to press the bead.
Numeral 4 denotes a shim disposed inside each die 2, and numeral 5 denotes a jaw disposed inside the shim 4, the longitudinal section of which has a wedge shape. Reference numeral 6 denotes a cone, which is a truncated cone having a plurality of inclined surfaces on the outer surface, and a through hole is formed in the center and in the axial direction. The short draw bar 8 is fitted into the through hole of the cone 6, and the short draw bar 8 and the cone 6 are integrated. Reference numeral 9 denotes a long draw bar connected to the short draw bar 8 via a double end nut. 7
Is a lubricating oil pipe for supplying lubricating oil to the sliding surfaces of the cone 6 and the jaw 5.

When the long draw bar 9 is moved to the left by an operating cylinder (not shown), the cone 6 is moved to the left, and the die 2 is pushed radially outward by the wedge action of the cone 6 and the jaw 5, and the steel pipe is removed. Push and straighten. Conversely, if the long draw bar 9 is moved to the right, the die 2 moves radially inward, the diameters of the dies 2 and 2 are reduced, and the steel pipe can be moved to the next step.

The present invention relates to a die having a clearance groove in the above-mentioned expansion pipe head, which solves the problem that the uncontacted portion on both sides of the bead of the steel pipe becomes large at the time of straightening and the steel pipe cannot be completely corrected. .

The first embodiment will be described with reference to FIG. Die 2
An escape groove 3 that can accommodate a bead having the largest bead width among steel pipes of a size to be straightened by an expansion head is provided in the center of the outer surface of the die 2 along the length direction of the die 2. Reference numeral 10 denotes a storage groove for a correction body, which is formed in the die 2 and opens in the side bottom surface of the clearance groove 3, and the storage groove 10 is provided on both sides of the clearance groove 3. Along 2
Articles are provided. The storage groove 10 has a cross section
The width of the opening is narrow, and the width of the bottom is wide.

A straightening body 11 having a length substantially equal to the length of the storage groove is slidably engaged with the storage groove 10 in the inside and outside directions of the die 2. The cross-sectional shape of the straightening body 11 is composed of a narrow portion that engages with the narrow portion of the storage groove 10 and a wide portion that engages with the wide portion of the storage groove 10, and between the narrow portion and the wide portion. A stepped portion is formed at the bottom. The front end 11a and the rear end of the correction body 11 are processed into a curved surface. The compression springs 16 to 16 are attached at regular intervals between the stepped portion of the storage groove 10 and the stepped portion of the correction body 11.
1 is always biased inward of the die 2.

A cylinder hole 12 into which a wedge-shaped cam piston 13 is fitted is formed in the die 2 so as to intersect the bottom of the storage groove 10 at right angles. A plurality of cylinder holes 12 are arranged at regular intervals along the length direction of the storage groove 10. A compression spring 15 is mounted between the tip of the cylinder hole 12 and the tip of the cam piston 13. Also, the rear end of the cylinder hole 12 and the cam piston 13
A pressure oil chamber 14 through which pressure oil flows in and out is provided between the rear ends of the pressure oil chambers.

When straightening a steel pipe having a large non-contact portion on both sides of the bead, pressure oil is supplied to the pressure oil chamber 14 and the cam piston 13 is advanced against the compression spring 15 so that the straightening body 1
1 is pushed out to the upper surface of the escape groove against the compression spring 16.
After that, the steel pipe is straightened by expanding the pipe expansion head. By doing so, the non-contact portions on both sides of the bead which could not be corrected conventionally can be corrected by the correction body 11.

When straightening a steel pipe having a small non-contact portion on both sides of the bead, if the pressure oil in the pressure oil chamber 14 is discharged, the cam piston 13 is retracted by the compression spring 16 and thereafter,
The compression spring 16 causes the correction body 11 to retreat to the retreat limit.
After this, even if the pipe expansion head is expanded and the steel pipe is straightened,
Since the correction body 11 does not press the bead, problems such as cracking of the bead caused by pressing the bead can be prevented.

As described above, if the straightening body 11 is moved in and out according to the change of the steel pipe size (change of the bead width), the roundness of the steel pipe can be achieved without changing the die.

Next, a second embodiment will be described with reference to FIG. 2
Reference numeral 0 denotes a single engaging groove which is opened at the center of the outer surface of the die 2 at the clearance groove 3 and is substantially equal to the width of the clearance groove and formed over the entire length of the die. A plate-shaped correction body 22 is slidably engaged with the engagement groove 20 inward and outward. This correction body 22
It has a cross-sectional shape in which ridges having curved heads 22a are formed at both ends of the rectangle. A plurality of jack holes are formed in the die 2 at intervals along the bottom centerline of the engagement groove 20. Jacks 21 to 21 are attached to each of these storage holes, and the rod of the jack 21 is connected to the bottom surface of the correction body 22. The straightening body 22 rises or falls along the side wall of the engagement groove 20 by supplying or discharging pressure oil to or from the jack 21.

When the jack 21 reaches the upper limit of the stroke, the top of the straightening body head 22a coincides with the upper surface of the escape groove 3, and when the jack 21 reaches the lower limit of the stroke, the top of the head 22a fits the escape groove. 3 is set below the bottom surface.

In this embodiment, when straightening a steel pipe having a large non-contact portion on both sides of the bead, each jack 21
After the pressure oil is supplied to .about.21 and the top of the straightening body head 22a is made to coincide with the upper surface of the escape groove 3, the steel pipe is straightened by enlarging the pipe expansion head. Also, when the size of the non-contact portion on both sides of the bead is small, the pressure oil of each jack 21 to 21 is discharged, and the top of the straightening body head 22a is positioned below the bottom surface of the escape groove 3, and then the expansion head is expanded. To correct the steel pipe. Thus, the correction body head 22a does not press the bead during correction.

Next, a third embodiment will be described with reference to FIGS. In FIG. 3, reference numeral 30 denotes an opening in the center of the outer surface of the die 2 at the escape groove 3 portion, the width of the opening is substantially equal to the width of the escape groove 3, and one engagement formed over the entire length of the die. It is a groove. The engagement groove 30 has a cross-sectional shape in which the outermost portion is rectangular, and from the outside toward the inside, an inverted trapezoid having a longer side shorter than the longer side of the rectangle continues, and further, a rectangle continues to the shorter side of the inverted trapezoid. ing. Stepped portions 30a, 30a are formed at the connection portion between the outermost rectangle and the long side of the inverted trapezoid.

As shown in FIG. 5, a plate 31 and a wing plate 3 rotating on both sides of the plate 31 are provided inside the engagement groove 30.
A correction body composed of 3, 33 is stored. Plate 31
Has a cross-sectional shape having a curved head portion 31a on one of the rectangular short sides, and has a shaft 32 extending in the longitudinal direction between the two end surfaces in the longitudinal direction. The wing plate 33 includes a plate portion 33b, a pressing portion 33a, and arms 33c and 33c. The pressing portion 33a is inclined at one end in the width direction of the plate portion 33b with respect to the plate portion, and extends over the entire length of the plate portion. Is formed. The pressing portion 33a has a curved head on one side and a contact surface that contacts the stepped portion 30a on the other side.

A plurality of compression springs 34 to 34 are attached to the bottom groove of the engagement groove 30 at regular intervals as shown in FIG. As a result, as long as the plate 31 is not pushed down by the beads, the heads 31 of the plate 31 are
a is at the upper limit position.

When straightening a steel pipe having a large non-contact portion on both sides of the bead (both the width and the height of the bead are small), the plate 3
The first head 31a is not pushed down by the bead, and the pressing portions 33a, 33a of the wing plate body 33 are supported by the stepped portions 30a, 30a of the engagement groove 30. Thus, when the expanding head is enlarged, the pressing portions 33a, 33a of the wing plate body 33 are expanded.
Can press on both sides of the bead to straighten the steel pipe.

When straightening a steel pipe having a small non-contact portion on both sides of the bead (both the width and height of the bead),
In this case, the head 31 of the plate body 31
a is pushed down by the beads against the compression springs 34-34. As a result, the shaft 32 is also lowered as shown in FIG. 4, so that the wing plate bodies 33, 33 are turned around the shaft 32 and narrow, and are disengaged from the stepped portions 30 a, 30 a to tilt the inverted trapezoidal portion. Go down. That is, the pressing portion 33 of the wing plate body 33
Since a falls below the bottom surface of the escape groove 3, the pressing portion 33a does not push up the bead.

FIG. 6 shows a die of a fourth embodiment in which the stepped portion 30a of the engagement groove 30 of the third embodiment is formed as an inclined stepped portion 30b. Thus, when straightening a steel pipe having small non-contact portions on both sides of the bead (both the width and height of the bead), the pressing portion 33a of the wing plate body 33 is likely to come off the stepped portion 30a of the engagement groove 30. As a result, the plate 31 and the wing plates 33 move more smoothly.

[0032]

Since the present invention is configured as described above, the following effects can be obtained. In the dies according to the second and third aspects, when the dimension of the non-contact portion is large, the straightening body can be pushed up to the upper surface of the relief groove and straightened.

In the die of the fourth aspect, two wing plate members having a pressing portion are rotatably provided on a plate member which is depressed so as to be pushed outward by a compression spring. The pressing part is automatically positioned according to the size of the contact part, and correction can be performed.

That is, according to the die of the present invention, the non-contact portions on both sides of the bead which could not be corrected conventionally can be corrected, the efficiency is not reduced by the rearrangement of the die, and a steel pipe having good roundness can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a die of a tube expansion head according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a die of a tube expansion head according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a die of a tube expansion head according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a state where a wing plate body according to a third embodiment of the present invention is turned inward.

FIG. 5 is a partial plan view of a third embodiment according to the present invention.

FIG. 6 is a sectional view of a die of a tube expanding head according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a state where a wing plate body according to a fourth embodiment of the present invention is turned inward.

FIG. 8 is a longitudinal sectional view of a mechanical pipe expanding head.

FIG. 9 is a sectional view taken along line AA of FIG. 8;

FIG. 10 is a view showing a straightening state of a steel pipe seam portion (bead) by a pipe expanding head die.

[Explanation of symbols]

 Reference Signs List 1 steel pipe 1a bead 2 die 3 relief groove 4 shim 5 jaw 6 cone 8 short draw bar 9 long draw bar 10 storage groove 11 straightening body 11a tip 12 cylinder hole 13 cam piston 14 pressure oil chamber 15 compression spring 16 compression spring 20 engagement groove 21 Jack 22 Straightener 22a Head 30 Engagement groove 30a Stepped portion 30b Stepped portion 31 Plate 31a Head 32 Shaft 33 Blade plate 33b Plate 33a Pressing portion 33c Arm 34 Compression spring

Claims (4)

[Claims] 1. A die for correcting the periphery of a bead portion of a steel pipe,
A die for a mechanical tube expander, wherein a straightening body extending in a die length direction is provided on both sides of a bead so as to be able to protrude and retract into a relief groove. 2. The die for a mechanical expander according to claim 1, wherein a cam piston engaged with the straightening member extending in the die length direction is configured so that the straightening member is protruded and retracted in an escape groove by pressure oil and a compression spring. 3. The die for a mechanical expander according to claim 1, wherein the straightening body extending in the die length direction and having ridges formed at both ends is made to protrude and retract into a relief groove by a hydraulic jack. 4. A wing plate body extending in the die length direction and having a pressing portion at an end is rotatably mounted on the left and right sides of the plate body extending in the die length direction, and said plate body is compressed by a compression spring. 2. The die for a mechanical expander according to claim 1, wherein the straightening body is urged so as to be pushed out of the die so that the straightening body is formed in the escape groove.