JPS6068130A - Method and device for forming cylindrical object - Google Patents

Abstract

PURPOSE:To provide a titled device which works a thin-walled and long-sized pipe to various diametral sizes with good accuracy by changing the relative positions of collet-shaped split dies inserted and disposed onto a tapered mandrel to attain a prescribed outside diameter and pressing the cylindrical blank material inserted therein by a pressing jig. CONSTITUTION:Collet-shaped split dies 13 having an internally tapered head part are inserted into a tapered mandrel 12 and the relative positions thereof are changed to adjust the outside diameter in the head part of the dies 13 to a prescribed diametral size. A cylindrical blank material 17 inserted onto such dies is pressed by a pressing jig 16 while the material 17 is rotated. The material 17 is formed into a thin-walled and long-sized pipe having a prescribed inside diameter. Said pipe has good dimensional accuracy. Cylinders of various sizes are worked with the same dies 13 and the equipment is made inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for forming cylindrical objects, and is particularly suitable for forming thin-walled long objects. Various methods have been used, each with their own advantages and disadvantages. The outline is described below.

(1) Sheet metal processing/welding 2 This is the most commonly used method. After bending the plate material into a semicircle or arc shape with a press or bending roller, the butt part is welded.
to make a cylinder. This feature is easy to work with, has a good material yield, and can be made at the lowest cost. However, the drawbacks are that inspection of the welded part is expensive, the strength of the welded part is low compared to the base material, and it lacks reliability, and the cylindrical accuracy is poor. Also, it is not suitable for materials that are difficult to weld, such as high carbon steel.

121 fIA construction: Casting methods include centrifugal casting and melting. The former, centrifugal casting, has many quality problems compared to forged products, while the latter, melting, has no quality problems but has problems with accuracy and cost.

(3) Forging 2 Generally, methods for producing cylindrical objects by forging include ring milling and hole expansion, and special methods include tube spinning and rotary swaging. In the former ring mill and hole expansion work, a short cylindrical material is crushed between an entire roll or a mandrel and a pushing jig, and the material is stretched in the entire circumferential direction, and the diameter of the material becomes thicker as the work progresses.

Figure 1 is a conceptual diagram of ring mill processing. In the figure, a short cylindrical material 3, which is a workpiece, is
is compressed and rotated in the direction of the arrow to perform rolling. Figure 2 shows the shape of the workpiece before and after ring milling.As shown in Figure 2, the outer diameter of the cylindrical material 3 before processing becomes narrower due to ring milling, but the axial length changes. Small products 4 Totoru.

FIG. 3 is a conceptual diagram of the hole enlarging operation. In the figure, the cylindrical material 3 is pressed by the mandrel 5 inserted inside and the pushing jig 6 outside, and this portion is stretched in the circumferential direction. In this case as well, the outer diameter of the material increases as in ring milling, but the change in axial length is small.

The disadvantages of this ring mill and hole expansion work are the above-mentioned through holes, the deformation is in the radial direction, so it is difficult to ensure accuracy, the change in axial length is small, and when the material thickness is less than 5Qmg, processing is difficult. It is difficult to form thin-walled long cylinders, and the axial length that can be formed is limited to 4 to 6 times the wall thickness.

-J,? In tube spinning and rotary swaging, a mandrel is inserted into a cylindrical material, and the material is pressed against the mandrel from the outer periphery of the material using rolls or rollers, and the material is formed in the axial direction rather than the circumferential direction. Stretched to.

FIG. 4 is a conceptual diagram of tube spinning processing. Tube spinning processing involves rolling a cylindrical material 8 fitted into a mandrel 7 in the axial direction with a roll 9 pressed against the outer peripheral surface of the material. is driven, and the roll 9 follows this. FIG. 5 shows the shape of the workpiece before and after tube spinning processing, and the material 8 is processed into a product 10 with a small change in inner diameter and an elongated axial length.

Figure 6 is a conceptual diagram of rotary swaging processing. This is for roll 9 of the tube spinning mentioned above...
The cylindrical material 8 is inserted into the mandrel 7 using a spindle 11, and is pressed from above and below by the spindle 11, and is basically the same as tube spinning. Award, this rotary swaging machine is shown in Figure 6...Sima 11
In addition to the two-headed type, which has a total of two heads, various types of moats are manufactured, ranging from four-headed to multi-headed ones.

The disadvantages of tube spinning and rotary swaging are:
Both require specialized equipment, are difficult to convert to other uses, and cannot be adopted due to equipment costs unless a certain number of units are produced; the same equipment has significantly different dimensions. The inability to manufacture products.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a molding method and an apparatus t' for molding a large-diameter integral thin-walled elongated cylinder at a relatively low cost. be. The structure of the method for forming a cylindrical object of the present invention that achieves the above object is to insert a mandrel inside the cylindrical material and press it from the outer periphery of the material with a pushing jig to stretch the material in the axial direction. In the forming method, a tapered part is formed on a mandrel, a split die is placed on the tapered part, and the relative position of the split die and the tapered part is changed to expand or reduce the diameter of the split die, The material is pressed with a pushing jig on the splitting die with a predetermined diameter, and after processing, the diameter of the splitting die is reduced, the material is rotated by a predetermined angle to change the processing position, and the splitting die is pressed again. It is characterized by expanding the diameter to a predetermined diameter and repeating the suppressing process. Further, the configuration of the cylindrical object forming apparatus of the present invention is such that the cylindrical object forming apparatus inserts a mandrel inside the cylindrical material and presses the material from the outer periphery with a pushing jig to stretch the material in the axial direction. , a mantle 1/le having a tapered part formed therein, a divided die which is divided into a plurality of parts arranged on the outer periphery of the tapered part and is movable in the radial direction, and which face the divided die with a cylindrical material in between. The present invention is characterized by comprising a pressing jig for pressing the cylindrical material, and an adjusting device for changing the relative axial position of the mandrel and the dividing die to expand or contract the diameter of the dividing die.

Embodiments of the present invention will be described in detail below with reference to the drawings. 7th
The figure is a cross-sectional view of a die portion of an embodiment of the present invention, FIG. 8 is a cross-sectional view when the material is processed, and FIG. 9 is a cross-sectional view when the material is processed.

In the drawing, 12 is a mandrel, 13 is a split die,
14 is an adjustment device, 15 is another die, 16 is a pushing jig, 1
7 is a cylindrical material. The mandrel 12 has a tapered portion 12a having a rectangular cross section at its distal end, and its base end is connected to a known support device (not shown). A split die 13 divided into two is engaged with the tapered portion 12a of the mandrel 12 from above and below. The two divided dies 1.3 have a substantially cylindrical outer shape, and have a tapered part 12 inside.
A taper is formed to fit with a. Further, one end of the split die 13 is connected to an adjusting device 14, and the split die 13 is driven by the adjusting device 14 in the longitudinal axis direction of the mandrel 12 to change its relative position with the tapered portion 12a, thereby adjusting the taper. Its outer diameter is expanded or reduced by the action of .

Further, in this embodiment, another die 15 is fitted into the cylindrical portion 12b of the mandrel 12 adjacent to the tapered portion 12a.

On the other hand, pushing jigs 16 are disposed above and below the outer periphery of the mandrel 12. Each of the pushing jigs 16 has semicircular suppressing portions 16a on opposing surfaces, and is formed to have a relatively thin thickness in the axial direction. Furthermore, the pushing jig 16 is connected to a drive device (not shown), such as a known press or a press, so that a required pressing force can be applied.

Next, a molding method according to the invention will be explained. First of all,
Cylindrical material 17ffi mandrel 12, split die 13
Insert it on top. Here, if it is difficult for the material 17 to fit onto the split die 13, use the adjustment device 14 to position the split die 13 on the small diameter side of the tapered part 12a in advance to reduce the diameter, and after inserting the split die 13, Taper 13 m 12
The diameter may be expanded to a predetermined diameter by moving it to the larger diameter side of a. Next, the pushing jig 16 is driven and the dividing die 13 is
Above, the material 17 is pressed.

After pushing the pushing jig 16 a certain amount, the pushing jig 16 is moved backward, and the dividing die 13 is moved to the narrow diameter side of the tapered part 12a by the adjustment device 14 to reduce the diameter, and the material 17 is rotated a certain number of times. Move it to change the machining position. Then again split dice 1
3 is returned to its original position, the diameter is enlarged at a predetermined diameter groove, and the pushing jig 16 is driven to suppress the position. In this way, pressing by the pressing jig 16, diameter reduction of the split die 13,
The forming process is performed while changing the position of the cable material 17 by repeatedly rotating the cable material 17 and expanding the diameter of the dividing die 13. 18 in Figure 8 indicates the processed material part of the helmet.

In this way, the pushing jig 16 having the semicircular suppressing part 16a
By using this, the material 17 can be stretch-molded in the axial direction by suppressing the elongation of the material 170 in the circumferential direction and by making the pressing contact portion long in the circumferential direction and narrow in the axial direction. Here, the outer shape of the divided die 13 does not need to exactly match the inner diameter of the cylinder to be manufactured, and therefore the same divided die 13
Even with the same pushing jig 16, the inner diameter can be varied within a certain range, and it is also possible to process stepped cylinders.

On the other hand, in order to improve the rigidity of the cylinder, circumferential ribs are provided inside the cylindrical material 17, but conventionally, these ribs have been attached by welding after forming the cylinder, or have been attached to thick walls. However, according to this embodiment, as shown in FIG. 8, there is no pollution, as shown in FIG. : By using the gap 19 formed between the dies 15 and pressing that part with the pushing jig 16, it is possible to form a lip on the inner circumference of the p.

In this embodiment, the tapered portion 12 of the mandrel 12
a' has a square cross section, and the pressing part 16a of the pressing jig 16 has a semicircular shape, but the present invention is not limited to these shapes. That's fine! In order to prevent the material 17 from elongating in the circumferential direction, the pressing part 16a of the F-shape pressing jig 16 may have a shape of 7 or any other shape as long as the resultant force of the pressing force acts in the axial direction.

Furthermore, in this embodiment, the mandrel 12 and the dividing die 13
The support is performed from both the left and right sides, but depending on operational or location constraints, it may be preferable to support from the same direction, and these can be selected as appropriate.

FIG. 10 shows a pushing jig 16 having a V-shaped pushing part 16a'e.
In this case, it is possible to correspond to a certain range of material inner diameters by changing the inclination angle of the figure 7 shape.

As explained in detail with reference to the embodiments above, the present invention can be put into practical use immediately by attaching versatile mandrels and dividing dies to existing equipment such as presses, etc. It becomes possible to form thin-walled long cylinders, which has been considered difficult. Moreover, compared to conventional forging, sheet metal processing, and welding, it is possible to produce thinner and more precise shapes with higher precision and stability. In addition, since it is point contact processing, strong processing is possible with a small force, and a wide range of cylindrical processing is possible with the same pushing jig and the same split die, making it suitable for a wide variety of small-scale production.
, thin-walled long cylinders can be manufactured easily and inexpensively. Therefore, the present invention is extremely useful for manufacturing, for example, rocket motor cases and other cylinders for high-pressure containers that require particularly strict quality control and inspection.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of ring mill processing, Fig. 2 is an explanatory diagram of the shape of the workpiece before and after ring mill processing, Fig. 3 is a conceptual diagram of hole expansion work, Fig. 4 is a conceptual diagram of tube spinning processing, FIG. 5 is an explanatory diagram of the shape of the liquid kneaded product before and after tube spinning processing, FIG. 6 is a conceptual diagram of rotary swaging processing, and FIGS. 7 to 9 relate to an embodiment of the present invention.
The figure is a sectional view of the die part, FIG. 8 is a sectional view of the material when it is processed, FIG. 9 is a cross-sectional view of the material when it is processed, and FIG. FIG. In the drawing, 12 is a mandrel, 12a is a tapered portion, 13 is a dividing die, 14 is an adjustment device, 16 is a pushing jig, and 17 is a cylindrical material. Patent Applicant Mitsubishi Heavy Industries, Ltd. Sub-Agent Patent Attorney Shibe Mitsuishi (and 1 other person) Figure 1 Figure 3 Figure 4 Figure 6 Figure 5 Figure 8 10 Figure 7 Figure 8b Figure 1O Figure 6 (

Claims (2)

[Claims] (1) A method for forming a cylindrical object in which a mandrel is inserted into the inside of a cylindrical material and the material is stretched in the axial direction by pressing from the outer periphery of the material with a pushing jig, in which a tapered portion is formed on the mandrel and the material is stretched in the axial direction. A split die is placed on the section, and the relative position of the split die and the tapered section is completely changed to expand or reduce the diameter of the split die, and the material is pressed into a pushing jig on the split die that has a predetermined diameter. The method is characterized in that the diameter of the split die is reduced to rotate the material by a predetermined angle to change the processing position, and the diameter of the split die is expanded again to a predetermined diameter to repeat the suppression process. Forming force method for cylindrical objects. (2) In a cylindrical article forming apparatus that inserts a mandrel inside a cylindrical material and presses it from the outer periphery of the material with a pushing jig to stretch the material in the axial direction, a mandrel on which a tapered portion is formed; a dividing die which is divided into a plurality of parts and arranged on the outer periphery of the tapered part and is movable in the radial direction; a pushing jig which faces the divided die and the cylindrical material by sandwiching it therebetween and presses the cylindrical material; 1. An apparatus for forming a cylindrical object, comprising an adjusting device that changes the relative axial position of the mandrel and the divided die to expand or contract the diameter of the divided die.