JPH1082500A - Manufacturing of cylindrical body forming pressure container, manufacture of pressure container formed of the cylindrical body, cylindrical body, and pressure container formed of the cylindrical body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten a pressure container, reduce manufacturing cost, and dispense with a name plate by carrying out spinning work so as to form the wall thickness of at least one barrel part of two cylindrical bodies thinner than that of a bottom part. SOLUTION: A disk plate in which information is marked is pressed by means of pressing, and an upper side cylindrical body 3a and a lower side cylindrical body 3b. Spinning work is carried out on each barrel part 9 of the cylindrical bodies 3a, 3b. Namely, the upper side cylindrical body 3a is set to a main shaft part 5a of a spinning work machine, the upper side cylindrical body 3a is rotated around an axial core of a main shaft part 51 together with the main shaft part 51 by for example 1000rpm, and for example, the wall thickness of the barrel part 9 in an end plate part of 2.8mm is worked to 2.4mm. The fitting part of the lower side cylindrical part 3b is fitted to an opening part side end part 31 of the upper side cylindrical body 3a, and the lower side cylindrical body 3b is welded to the upper side cylindrical body 3a around an opening top part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cylindrical body for forming a pressure vessel such as an LP gas cylinder for 20 kg used at home, and a method for manufacturing a pressure vessel formed from the cylindrical body. And a cylindrical body and a pressure vessel formed from the cylindrical body.

[0002]

2. Description of the Related Art For example, a 20 kg LP gas cylinder for home use is generally manufactured by a manufacturing method shown in FIG. That is, for each of the two disks 2 and 6 each having a diameter of 695 mm cut from the steel plate 1 having a thickness of 2.5 mm and forming the main container portion of the LP gas cylinder, the peripheral portion of the disk 2 is fixed. By pressing in the state where
An upper tubular body 3a and a lower tubular body 3b having one end forming a substantially hemispherical bottom and the other end opened are produced. In the pressing operation, the thickness of the disk 2 is maintained at the bottom portion. The upper tubular body 3a and the lower tubular body 3b are joined at the respective opening side ends 31, 32, but the opening side ends of the lower tubular body 3b are easily joined. As shown in FIG. 7, the portion 32 is processed so as to form the fitting portion 6 narrowed inward. Then, after fitting the upper tubular body 3a to the fitting portion 6 of the lower tubular body 3b,
One container is formed by welding the fitting portions. Next, a valve 4 for opening and closing, a nameplate 5 for stamping the date of manufacture, and the like are attached to the ceiling mirror portion 7 corresponding to the bottom of the upper cylindrical body 3a, or the lower cylindrical body Skirt 11 on 3b
To complete the LP gas cylinder. Such an LP gas cylinder is filled with LP gas, and its internal pressure is 8 to 9 kg / cm ² at the time of shipment. Generally, when the internal pressure acts on the container, as shown in FIG. 7, when the pressure acting on the trunk portion of the container is P, the top plate and the base plate of the container are calculated to be twice the pressure P above. Pressure acts.
In addition, the top plate is engraved, and the base plate needs to be considered for corrosion. Therefore, when designing the pressure vessel, it is necessary to make the thickness of the top plate and the base plate portion thicker than the thickness of the trunk portion.

[0003]

However, as described above, the disk 2 having a predetermined thickness is pressed to form, for example, the lower cylindrical body 3b.
As described above, the thickness of the ground mirror portion 8 is substantially the same as the thickness of the disk 2 as described above, but the thickness of the body portion 9 is changed from the vicinity of the shoulder portion 10 to the opening side end portion. It gradually increases toward 32 and becomes thickest at the opening side end 32. This will be specifically described. The dashed line shown in FIG. 4 indicates the thickness of the lower cylindrical body 3b at each measurement point when, for example, the lower cylindrical body 3b is manufactured by pressing the circular plate 2 having a plate thickness of 2.8 mm. Shows the change in As shown in the figure, the measurement points are defined as the lowest point of the ground mirror 8 along the cross section of the lower cylindrical body 3b along the central axis of the formed lower cylindrical body 3b. 0 ”as 10m in each direction
The measurement points are provided at m pitches. As is clear from FIG. 4, the thickness of the ground mirror portion 8 substantially maintains the thickness of the disk 2 of 2.8 mm over the entire range thereof, and
The thickness gradually increases toward the opening-side end 32, and is 3.8 mm at the opening-side end 32.

As described above, the thickness of the mirror portion maintains the thickness of the disk 2 even when the press working is performed. Further, the thickness of the mirror portion needs to be greater than the thickness of the body portion. However, in the case of press working, the mirror portion and the body portion of the tubular body 3 are integrally formed. Therefore, the thickness of the disk 2 from which the cylindrical body 3 is formed is determined by the thickness of the mirror portion of the cylindrical body 3 on which the largest pressure acts when the internal pressure acts. On the other hand, by design,
The thickness of the body, which may be thinner than the thickness of the mirror, becomes larger than the thickness of the mirror, as described above, when the cylindrical body is manufactured by pressing. Is reality. As described above, in the related art, there has been a problem that the thickness of the body of the LP gas cylinder is unnecessarily thick, so that the weight of the LP gas cylinder increases.

[0005] In addition, the LP gas cylinder is engraved with a display of a legal inspection performed at regular intervals in addition to the date of manufacture as described above. However, the thickness of the ceiling mirror 7 is designed to be the minimum necessary from the viewpoint of the weight of the cylinder, the manufacturing cost, and the like. As a result, the thickness of the skylight section 7 is reduced, causing a problem in strength. Therefore, as described above, the nameplate 5 for engraving is welded to the ceiling mirror 7. As described above, the conventional LP gas cylinder has a problem that the engraving place is limited on the nameplate 5 and is inconvenient in work and handling. SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has a lighter weight than the conventional one, can reduce the manufacturing cost, and eliminates the need for a nameplate. It is an object of the present invention to provide a method, a method for manufacturing a pressure vessel formed from the above-mentioned tubular body, and a tubular body and a pressure vessel formed from the tubular body.

[0006]

According to a first aspect of the present invention, there is provided a method of manufacturing a cylindrical body comprising two cylindrical bodies each having a bottom at one end and an opening at the other end via a body. A method of manufacturing a cylindrical body in a pressure vessel formed by joining the respective openings, wherein at least one of the two cylindrical bodies has a thickness of the body smaller than a thickness of the bottom. In this case, the tubular body is manufactured by spatula drawing.

Further, according to a second aspect of the present invention, there is provided a method for manufacturing a pressure vessel, wherein each opening of each cylindrical body manufactured by the method for manufacturing a cylindrical body according to any one of claims 1 to 9. It is characterized by being manufactured by joining together.

[0008] Further, the cylindrical body in the third aspect of the present invention comprises:
It is manufactured by the method for manufacturing a cylindrical body according to any one of claims 1 to 9.

Further, in a pressure vessel according to a fourth aspect of the present invention, each opening of each cylindrical body manufactured by the method for manufacturing a cylindrical body according to any one of claims 1 to 9 is joined. It is characterized by being manufactured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is a method for manufacturing a cylindrical body, a method for manufacturing a pressure vessel formed from the cylindrical body, a cylindrical body manufactured by each of the above manufacturing methods, The pressure vessel and the pressure vessel will be described below with reference to the drawings. In each of the drawings, components that perform the same or similar functions are denoted by the same reference numerals. Further, in the present embodiment, an LP gas cylinder for 20 kg is taken as an example of the pressure vessel, but the present invention is not limited to this, and any pressure vessel formed by joining the respective openings of two cylindrical bodies can be used. It does not matter whether it is a pressure vessel or not. Further, in the present embodiment, a case is shown in which spatula processing is performed on both body portions of the first and second cylindrical bodies. However, the present invention is not limited to this, and spatula processing is performed on at least one of the cylindrical bodies. May be applied. Further, in the following description of the manufacturing method of the pressure vessel of the present embodiment,
Only the main steps of the manufacturing steps are shown. The method for manufacturing the pressure vessel includes the method for manufacturing the cylindrical body of the present embodiment, and the cylindrical body and the pressure vessel of the present embodiment are manufactured by these manufacturing methods.

As shown in FIG. 1, in a step (indicated by "S" in the figure) 1, an upper cylindrical body 3a is formed in the same manner as in the prior art.
In order to produce the lower cylindrical body 3b, the disk 2 is cut out from a steel plate having a predetermined thickness with a predetermined diameter. In the present embodiment, the thickness of the disc 2 is 2.8 mm, which is larger than the conventional 2.5 mm, in order to eliminate the use of the name plate 5 as described later. The diameter of the disk 2 is 631 m, which is smaller than the conventional 695 mm.
m. The outer diameters of the upper cylindrical body 3a and the lower cylindrical body 3b to be manufactured are 321 mm as in the conventional case, and the axial lengths of the upper cylindrical body 3a and the lower cylindrical body 3b are the same as those in the conventional case. Are identical. As described above, since the diameter of the disk 2 can be smaller than in the conventional case, it is possible to cut out a larger number of disks 2 from a single steel plate than in the conventional case, and to reduce the manufacturing cost. However, the weight of the LP gas cylinder, which is the final product, can be reduced by about 1.8 to 1.9 kg compared to the related art.

Next, after the information which has been conventionally engraved on the nameplate 5 is engraved on the disk 2, in Step 2, the disk 2 is pressed in the same manner as in the prior art to respectively press the upper cylindrical body 3 a and the lower cylindrical body. The body 3b is prepared. Pressing method is the same as in the past.
Is fixed to the peripheral portion of the disk 2 and the central portion thereof is pressed. The thickness of the top mirror portion 7 and the ground mirror portion 8 is maintained at 2.8 mm, which is substantially equal to the thickness of the disk 2.

In step 3, spat-drawing is performed on each of the body portions 9 of the upper tubular body 3a and the lower tubular body 3b. Incidentally, the spatula drawing is a known processing method,
The spatula machine used is also known. or,
In the following description in step 3, the description will be given taking the upper cylindrical body 3a as an example, but the same processing is performed for the lower cylindrical body 3b. As shown in FIG. 2, the upper cylindrical body 3 a is set on the main shaft part 51 of the spatula drawing machine, and the upper cylindrical body 3 a is rotated together with the main shaft part 51 at 1000 rpm by an arrow 52 around the axis of the main shaft part 51. Rotate as shown. Also, as described above, in the press working, the upper cylindrical body 3a
The thickness of the body 9 gradually increases from the shoulder 10 toward the opening-side end 31. Therefore, in order to correct the thickness of the body 9 to an appropriate thickness according to the internal pressure, the throttle member 53 is pressed from the shoulder 10 of the upper tubular body 3a to the opening side end 31 while pressing the body against the body 9. By moving, the body 9 is drawn. Specifically, the trunk 9 in the present embodiment
Is 2.4 mm, and in order to correct the above-mentioned 2.4 mm from the shoulder portion 10 to the opening side end 31, the diaphragm member 53 is moved in the I direction orthogonal to the axis of the main shaft portion 51. To the body 9 with a force of about 90 KN
1000mm / mi to II with the same thrust of about 90KN
It moves at a moving speed of n. The shoulder portion 10 is a portion that transitions from the top mirror portion 7 to the body portion 9 and is a portion where the curved surface forming the top mirror portion 7 disappears. The trunk 9 refers to a section from the shoulder 10 to the opening-side end 31. FIG.
As shown in the figure, the diaphragm member 53 is provided on the peripheral surface of the upper cylindrical body 3.
Are arranged. As shown by the solid line in FIG. 4, by performing spatula processing on the trunk portion 9 in this manner, the thickness of the trunk portion 9 is approximately 2.4 mm with respect to the top mirror portion 7 whose thickness is approximately 2.8 mm. Processed into In addition, what is indicated by a dashed line is the thickness of the skylight portion 7 and the body portion 9 before the spatula drawing process,
The thickness of the body portion 9 before the spatula drawing is gradually increased from the shoulder portion 10 toward the opening side end 31. You can see that it was done.

In step 4, the opening side end 31 of the upper cylindrical body 3a and the opening side end 32 of the lower cylindrical body 3b are processed. That is, as shown in FIG. 5, the fitting portion 6 is formed at the opening side end 32 of the lower cylindrical body 3b as in the conventional case. The opening side end 31 of the upper cylindrical body 3a is configured such that the axial length of the upper cylindrical body 3a is a predetermined length, which is 340 mm in the present embodiment, and Laser or plasma cutting is performed so as to form a groove 33 that is inclined upward from the inside toward the outside.

At step 5, the valve 4 for opening and closing is attached to the ceiling mirror 7 of the upper cylindrical body 3a, and the lapping is performed on the ground mirror section 8 of the lower cylindrical body 3b, as in the prior art. Processing is performed. In step 6, the fitting portion 6 of the lower cylindrical body 3b
And the opening-side end 31 of the upper cylindrical body 3a are fitted, and the lower cylindrical body 3b and the upper cylindrical body 3a are welded around the groove 33. As described above, in the present embodiment, the groove 33 is provided and the welding is performed around the groove 33, so that the welding is performed from the peripheral surface 34 of the upper cylindrical body 3a and the lower cylindrical body 3b. Projecting bead height IV
Can be reduced to almost half the height of the conventional one. When transporting the LP gas cylinder, the operator must
Often a gas cylinder is carried over the shoulder. At this time, since the welded portion is a portion just hitting the shoulder of the worker, the bead height of the weld is reduced as compared with the related art,
This has the effect of reducing the pain on the shoulder during transportation for the worker.

In step 7, the welded upper cylindrical body 3
In order to complete the a and the lower cylindrical body 3b as an LP gas cylinder, for example, a support is mounted around the valve 4, a pressure tightness test, painting, and the like are performed. Thus, the LP gas cylinder is completed. As described above, in the present embodiment, the thickness of the trunk portion 9 can be made to match the design calculation value when the internal pressure is applied by performing spatula drawing on the trunk portion 9. Further, since the body portion 9 is elongated in the axial direction by the spatula drawing, the size of the plate material for forming the upper tubular body 3a and the lower tubular body 3b can be reduced as compared with the related art. Therefore, the weight of the LP gas cylinder can be reduced, and the manufacturing cost can be reduced. In addition, since the body 9 was subjected to spatula drawing to set the body 9 to an appropriate thickness,
The thicknesses of the skylight unit 7 and the earth mirror unit 8 can be made thicker than before. Therefore, the upper cylindrical body 3a and the lower cylindrical body 3
As for the plate material for forming b, it is possible to use a thicker plate material than before. Therefore, direct engraving can be performed on the upper cylindrical body 3a or the lower cylindrical body 3b, and the attachment of the nameplate 5 is not required.

In the above-described embodiment, the disk 2 is pressed to form a tubular body in advance, and the body 9 of the tubular body is subjected to the spatula drawing. However, the present invention is not limited to this. Alternatively, the tubular body may be formed by spatula drawing from the state of the plate material. In this case, a mirror portion is first formed by moving the stop member 53 along a main shaft portion 51 having a hemispherical tip as shown in FIG. 2, and thereafter, as described above, the main shaft portion 51 is formed.
The diaphragm member 53 is moved along the axial direction of (3) to form a body. In this case, it is necessary to control the pressing force and thrust of the throttle member 53 so that the thickness of the bottom portion is larger than the thickness of the body portion.

[0018]

As described in detail above, the method of manufacturing a cylindrical body according to the first aspect of the present invention, the method of manufacturing a pressure vessel formed from the cylindrical body of the second aspect, and the manufacturing method of the third aspect of the present invention. According to the cylindrical body manufactured from the above, and the pressure vessel formed from the cylindrical body of the fourth aspect, at least one of the first and second cylindrical bodies is subjected to the spatula-drawing process, and the body portion has a meat. Since the thickness is smaller than the thickness of the bottom portion, the area of the material necessary for forming the first and second cylindrical bodies can be reduced as compared with the conventional case, and the weight and the manufacturing cost can be reduced. Can be. In addition, since the thickness of the bottom and the body can be freely set by adopting a spatula drawing process, the thickness of the bottom can be set to a thickness that allows direct engraving on the bottom. Thus, a nameplate for engraving can be eliminated.

[Brief description of the drawings]

FIG. 1 is a flowchart showing steps of a method for manufacturing a tubular body according to an embodiment of the present invention.

FIG. 2 is a plan view schematically showing a spatula drawing machine used in the spatula drawing shown in FIG.

FIG. 3 is a sectional view taken along line III-III shown in FIG. 2;

FIG. 4 is a graph showing a state of a wall thickness before and after the spatula drawing shown in FIG. 1 is performed.

FIG. 5 is a cross-sectional view showing a state where the opening-side ends of the upper tubular body and the lower tubular body shown in FIG. 1 are processed.

FIG. 6 is a view showing a manufacturing process of a conventional LP gas cylinder.

FIG. 7 shows a conventional upper cylindrical body and lower cylindrical body.
It is sectional drawing which shows the state which processed those opening part side edge part.

[Explanation of symbols]

2 ... disk, 3 ... tubular body, 3a ... upper tubular body, 3b ... lower tubular body, 5 ... nameplate, 6 ... fitting part, 7 ... top mirror part, 8 ... ground mirror part, 9 ... Body, 10 ... shoulder, 31, 32 ... opening side end, 33 ... groove.

Claims (14)

[Claims] 1. Each of the openings of two cylindrical bodies (3a, 3b) having a bottom (7, 8) at one end and an opening at the other end via a body (9). A method for manufacturing a cylindrical body in a pressure vessel formed by joining, wherein at least one of the two cylindrical bodies has a thickness smaller than a thickness at the bottom portion of the body.
A method for manufacturing a cylindrical body, comprising manufacturing the cylindrical body by spatula drawing. 2. After manufacturing at least one of the two tubular bodies by the spatula drawing, an opening side end (32) of one of the two tubular bodies is provided with: The opening side end of the one cylindrical body is covered by the opening side end (31) of the other cylindrical body, and the opening side end of the one cylindrical body and the other cylindrical body. Forming a fitting portion (6) that can be fitted with the opening side end of the other cylindrical body, and climbing from the inside to the outside of the other cylindrical body at the opening side end of the other cylindrical body. The method for producing a tubular body according to claim 1, wherein a groove having an inclination is formed. 3. The method for manufacturing a tubular body according to claim 1, wherein when at least one of the two tubular bodies is manufactured from a plate, the spatula drawing is performed from a state of the plate. 4. Pressing the plate material while maintaining the thickness of the plate material as the thickness of the bottom portion to produce at least one of the two tubular bodies, and then removing the at least one tubular body produced The method for producing a cylindrical body according to any one of claims 1 to 3, wherein the spatula processing is performed on the body (9). 5. The method for producing a cylindrical body according to claim 4, wherein said spatula drawing is performed on both body portions of said two cylindrical bodies. 6. The method for producing a cylindrical body according to claim 1, wherein the thickness at the bottom portion and the thickness at the body portion are substantially constant at respective portions. 7. The method for manufacturing a cylindrical body according to claim 1, wherein the thickness of the bottom of at least one of the two cylindrical bodies is a thickness that can be directly imprinted on the bottom. . 8. The method for producing a cylindrical body according to claim 1, wherein the two cylindrical bodies form a LP gas cylinder for 20 kg. 9. The method according to claim 1, wherein the thickness at the bottom is 2.8 mm, and the thickness at the body is 2.4 mm. 10. A pressure vessel manufactured by joining respective openings of each of the cylindrical bodies manufactured by the method for manufacturing a cylindrical body according to claim 1. Manufacturing method. 11. A method for manufacturing a pressure vessel by welding each opening of each cylindrical body manufactured by the method for manufacturing a cylindrical body according to claim 2 to manufacture a pressure vessel. A method for manufacturing a pressure vessel, wherein the welding is performed centering on the groove so as to reduce the height of protrusion of a weld bead from an outer peripheral surface of a cylindrical body. 12. A tubular body produced by the method for producing a tubular body according to claim 1. Description: 13. A pressure produced by joining the respective openings of the respective cylindrical bodies manufactured by the method for manufacturing a cylindrical body according to claim 1. Description: container. 14. A pressure vessel manufactured by welding each opening of each cylindrical body manufactured by the method for manufacturing a cylindrical body according to claim 2 to manufacture the pressure vessel. A pressure vessel, characterized in that the welding is performed around the groove so as to reduce the height of the weld bead projecting from the outer peripheral surface of the cylindrical body.