JPH08309441A - Tube forming device - Google Patents

Abstract

PURPOSE: Not to generate pin hole and wrinkle at a joined part of tube by forming with plural forming rolls, adjusting a height of forming roll and making the guide route of metal sheet to curved shape. CONSTITUTION: A forming means 13 of tube is constituted so that plural rolls 14,15, 16 are arranged in series with some interval. Each roll 14, 15, 16 regulates the guided route of metal tape 12 (metal sheet) while at each assembly, each bracket 18, 19, 20 are supported to a floor face 21 through an extending/ retracting mechanism of a hydraulic cylinder 22 and at each assembly, the height position from floor face 21 is adjusted. For example, a third assembly forming roll 16 is adjusted to the height to give reference based on the relation of welding means 17 while controlling the actuation of hydraulic cylinder device 22 to elevate its bracket 20. By this method, the guide route of metal sheet 12 is made to curved shape, as a result, appropriate warp is given to the metal sheet 12, high quality tube is easily produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube forming device suitable for forming a metal sheath of a power cable, for example.

[0002]

2. Description of the Related Art In a device for forming a metal sheath of a power cable, a strip-shaped metal plate, that is, a metal tape is formed in a stepwise tubular shape so as to vertically attach a continuously fed cable and cover it. Forming means is provided. This forming means includes a roll forming device, a forming tube device, a die forming device and the like.

In a roll forming apparatus, a plurality of pairs of forming rolls are arranged in series so as to define a guide path for the metal tape to be formed, and the metal tape is gradually stepped between the rolls. It is molded into a tube. In the forming tube device, a metal tape is guided inside a forming tube having a tapered conical shape, and the metal tape is sequentially formed along the inner surface of the forming tube into a tubular shape. Further, in the die forming device, the metal tape is formed into a tubular shape by using a die.

In any case, in these devices, the metal tape molded by the molding means is as shown in FIGS.
As shown in (b) respectively, the flat metal tape is sequentially bent so that both edges thereof come close to each other, and finally, both edges facing each other abut each other to form a perfect circular cross section. It is molded so as to have a surface shape.

[0005]

By the way, as shown in FIG. 4, the metal tape 1 to be subjected to the above-mentioned forming has both sides in the forming zone 4 extending from the flat plate-shaped portion 2 to the circular cross-sectional shape portion 3. Due to the joining of the edges, it is stretched to a dimension (L + α) larger than the longitudinal dimension (L) at the bottom opposite to the edges. FIG.
Assuming that the elevation angle of the edge portion in the molding zone 4 shown in (b) is θ, the relationship of cos θ = L / (L + α) is established.
Therefore, both edges are stretched in the longitudinal direction. Therefore, there is a possibility that a pinhole may be formed at the joint portion of the metal tape 1 due to this stretching, and the stretched portion may cause wrinkles after molding. Then, the objective of this invention is providing the tube forming apparatus which does not produce a pinhole and a wrinkle in a junction part.

[0006]

The apparatus of the present invention is a tube forming apparatus provided with a forming means for forming a strip-shaped metal plate into a tubular shape in which edge portions which are partially and stepwise opposed to each other are brought close to each other in a tubular shape. The means are a plurality of sets of forming rolls that are arranged in series in pairs and form strip-shaped metal plates guided between them in a tubular shape with the edges thereof facing each other partially and stepwise in close proximity to each other. And the height position of at least one forming roll in each set is adjustable.

[0007]

In the forming apparatus of the present invention, the guide path for the metal plate defined by the forming means is curved so that the metal plate can be easily warped appropriately in the direction of contracting the joint edge. It is possible to effectively suppress the elongation of both edges of the metal plate. Further, the forming means is composed of a plurality of sets of forming rolls, and the height position thereof can be adjusted, so that a guide path is appropriately provided so as to give an optimum warpage amount to the metal plate guided between the forming rolls. It becomes possible to adjust.

[0008]

The present invention will be described in detail below with reference to the illustrated embodiments. 1 and 2 are a front view and a plan view, respectively, schematically showing a tube forming apparatus according to the present invention. As shown in FIG. 1, the pipe forming apparatus 10 according to the present invention forms a continuous strip-shaped metal plate, that is, a metal tape 12, such as aluminum or iron drawn from a supply drum 11 into a tubular shape stepwise. Forming means 13 for

In the illustrated example, the forming means 13 is constituted by, for example, three sets of forming rolls 14, 15 and 16 each forming a pair, as shown in FIGS. 1 and 2. Forming rolls 14, 15 and 16 of each set are
The sets are arranged in series at a distance from each other so as to guide the metal tape 12 from the supply drum 11 to a welding means 17 such as a welding torch.

3 (A) to 3 (C) are respectively shown in FIG.
FIG. 9 is a cross-sectional view taken along line AA to line C-C shown in FIG. The pair of forming rolls 14 (14a, 14b) of the first set closest to the supply drum 11 are arranged so that they are vertically aligned with each other, for example, via a U-shaped bracket 18 that opens upward. The metal tape 12 is supported between 14a and 14b so as to be molded. As clearly shown in FIG. 3A, the upper forming roll 14 of the pair of forming rolls 14 of the first set is formed.
Reference character a is a so-called male-shaped roll having a bale shape as a whole, and the lower forming roll 14b is a female roll for receiving the upper forming roll 14a. The metal tape 12 is formed by both forming rolls 14.
By passing between a and 14b, pre-forming is performed so that both edges rise up toward the upper forming roll 14a.

A second pair of forming rolls 15 (15a, 15a) arranged on the downstream side of the first forming roll 14
Are supported so as to be laterally spaced from each other, for example, via U-shaped brackets 19 that open laterally on the side of the guide path. The pair of forming rolls 15a and 15a of the second set have arcuate groove-shaped outer peripheral surfaces and are symmetrical to each other, as clearly shown in FIG. 3 (B). The metal tape 12 that has been preformed by the pair of forming rolls 14 of the first set passes through the forming rolls 15a and 15a to open upward, so that
Bending is performed so as to have a V-shaped cross section.

The pair of forming rolls 16 (16a, 16a) of the third set closest to the welding means 17, like those in the second set, are laterally spaced from one another, for example in It is supported via a bracket 20 having a character shape. Third pair of forming rolls 16 (16a,
16a), as clearly shown in FIG.
They have semicircular groove-shaped outer peripheral surfaces and are symmetric to each other. Second
The metal tape 12 bent and bent into a C-shape by the pair of forming rolls 15 has the forming rolls 16a and 16a.
By passing through a, final molding is performed so that the edges facing each other abut and have a circular cross-sectional shape.

The portions of the metal tape 12 that have been finally molded to have a circular cross-sectional shape are sequentially joined at the joining edges by the welding means 17, thereby forming a continuous pipe. In forming the sheath of the power cable, the cables are extended in parallel to the metal tape 12 delivered from the supply drum 11, and the metal tape 12 is vertically attached to the metal tape 12 so as to be housed inward so that the metal tape 12 undergoes a forming process. However, the cables have been removed from each drawing to simplify the drawings.

First to third sets of forming rolls 14 and 15
And 16 provide the stepwise molding of the metal tape 12 between each pair of rolls, as well as defining guideways for the metal tape 12. Each of the forming rolls 14, 15 and 16 defining this guide path is, for example, a hydraulic cylinder so that the height position from the floor surface 21 can be adjusted for each set, referring to FIG. 1 again. Each bracket 18, through a telescopic mechanism such as the device 22,
19 and 20 are supported on the floor surface 21.

The third set of forming rolls 16 is adjusted to a height position which gives a reference in relation to the welding means 17 by controlling the operation of the hydraulic cylinder device 22 which moves the bracket 20 up and down. Instead of the hydraulic cylinder device 22 that adjusts the height position of the third set of forming rolls 16, a fixed support mechanism can be used.

The forming rolls 15 of the second set are adjusted by adjusting the hydraulic cylinder device 22 for moving the brackets 19 thereof up and down.
It is located slightly above the height position of the forming rolls 16 of the third set. Therefore, in the portion of the metal tape 12 guided from the second set of forming rolls 15 to the third set of forming rolls 16, the line along the bottom of the metal tape 12 located below the upper edge of the metal tape 12 is The straight line as shown in FIG. 4B is not formed, and an upward warp is provided when viewed from the third set of molding rolls 16 to the second set of molding rolls 15 side.

In the first group of forming rollers 14, the gap between the forming rollers 14a and 14b is adjusted to the height of the second group of forming rollers 15 by adjusting the hydraulic cylinder device 22 which moves the bracket 18 up and down. Located further up than. Therefore, the first set of forming rolls 1 of the metal tape 12
In the part guided from 4 to the forming roll 16 of the third set,
The line along the bottom portion of the metal tape 12 located below the upper edge portion has an arc shape that opens upward.

As a result, the metal tape 12 guided by the forming rolls 14 and 15 of the first set and the second set to the forming rolls 16 of the third set is generally opened upward in this guide region. Given an arcuate warp. This arcuate warp applies a compressive force in the longitudinal direction to the edge portion located above the metal tape 12. Since this compressive force suppresses the edge portion of the metal tape 12 from being stretched, the conventional stretching does not occur in the edge portion in the above-described forming step, and pinholes or wrinkles due to this elongation do not occur. Tubes are manufactured.

Instead of using an adjusting mechanism such as each cylinder device 22, each bracket 18 and 19 may be fixedly held at a predetermined height position such that the guide path exhibits a predetermined arcuate curve. it can. However, according to the rigidity of the metal tape 12, etc., in order to make it possible to adjust to an ideal arc-shaped curve such that the edge portion and the bottom portion of the metal tape 12 are equal in the guide region, as shown in the figure, the adjusting mechanism Is preferred.

The present invention is not limited to the above embodiments. Although the present invention has been described with respect to the formation of the metal sheath of the power cable, the present invention is not limited to this and can be applied to the formation of various tubular bodies. Further, although an example of the roll forming device provided with a large number of forming rolls has been described as the forming means, the present invention can be applied to a forming tube device and a die forming device or a combination thereof. Further, in order to support the forming roll so that its height position can be adjusted, various adjusting mechanisms can be applied instead of the expanding and contracting mechanism such as the hydraulic cylinder device.

[0021]

According to the apparatus of the present invention described above, the guide path for the metal plate defined by the forming means is curved so that the metal plate can be appropriately warped. Therefore, the present invention can be easily carried out, whereby a high-quality tube without pinholes and wrinkles can be easily manufactured. Further, the forming means is composed of a plurality of sets of forming rolls, and the height position thereof can be adjusted, so that a guide path is appropriately provided so as to give an optimum warpage amount to the metal plate guided between the forming rolls. Being able to adjust allows for easier manufacture of higher quality tubing.

[Brief description of drawings]

FIG. 1 is a front view schematically showing a tube forming apparatus according to the present invention.

FIG. 2 is a plan view of the pipe forming apparatus shown in FIG.

3A is a cross-sectional view taken along the line AA shown in FIG. 2, and FIG. 3B is a cross-sectional view taken along the line BB shown in FIG. Yes, (C) is the line C- shown in FIG.
It is sectional drawing obtained along C.

4 (a) and 4 (b) are respectively a plan view and a front view showing a forming process of a metal plate in a conventional pipe forming method.

[Explanation of symbols]

 10 Tube Forming Device 12 Metal Tape (Strip Metal Plate) 13 Forming Means 14, 15, 16 Forming Roll

Claims (1)

[Claims] 1. A pipe forming apparatus comprising a forming means for forming a strip-shaped metal plate into a tubular shape in which edge portions facing each other in a partial and stepwise manner are brought close to each other, and each of the forming means forms a pair. However, a plurality of sets of forming rolls for forming a strip-shaped metal plate, which is arranged in series and is guided between the strip-shaped metal plates, are successively and partially and stepwise brought close to each other into a tubular shape. The height position of at least one pair of forming rolls is adjustable so that the amount of warp in the direction of contracting the joint edge of the metal plate guided between them can be adjusted. Forming equipment.