JPS63299840A - Production of exhaust pipe in electromagnetic wave generating device - Google Patents

Abstract

PURPOSE:To obtain the product of stabilized performance in mass quantity by forming a stepped hollow pipe from a billet by a multi-step type rolling mill and executing a finishing pipe expansion on the part of after pre-pipe expanding of the head of the hollow pipe by forming the parts of the head and leg. CONSTITUTION:The billet 6 executing an end face finishing on the cut billet cutting a bar stock in the specified dimension is formed and a stepped hollow pipe 18 is formed by executing a piercing work from both end faces of the billet 6. The parts of a head 19 and leg 20 are then formed with the forward extrusion method of the stepped hollow pipe 18, a pre-pipe expanding is executed once again on the part of the head 91 of the pipe 18 and the leg 20 is extended in the specified length. Finally, a finishing pipe expanding is executed on the part of after pre-pipe-expanding of the head 19 of the pipe 18. The product of stabilized performance is thus obtainable in mass quantity by the series of flow works of one unit of a multi-step type rolling mill.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of an exhaust pipe which is a component of an electromagnetic wave generator in a microwave oven.

[Conventional technology]

Conventionally, an exhaust pipe to be used in an electromagnetic wave generator is manufactured by manufacturing a blank (34) by cutting a ready-made hollow pipe (31) into nine pieces to a predetermined size, as shown in Fig. 3 (△). Then, as shown in FIG. 3(B), the blank (34) is
At the same time, the head (
19), and form a leg portion (20), and further, as shown in FIG. 3(C), the blank (34) is expanded into a tube expansion molding die (38). At the same time as pushing in with the sleeve (39), the tube expansion forming pin (40
) to expand the pipe at the head (19);
Then, the leg portion (20) is extended to a predetermined length, and then, as shown in FIG. At the same time as the tube is pushed in, a manufacturing method is adopted in which a finish tube expansion T is applied to the expanded portion of the head (19) using a finish forming pin (43).

Additionally, as shown in Figure 4 (A>), there is a hollow pipe (31) corresponding to the head (19), and as shown in Figure 4 ([3), there is a hollow pipe (31) corresponding to the leg (20). The hollow pipes (31) are individually cut into predetermined dimensions and processed, and then the process shown in Fig. 4 (
As shown in C), the hollow pipe (3) of the head (19)
1) and the hollow pipe (31) of the leg (20) were combined and fixed by welding.

Furthermore, a manufacturing method was adopted in which all processes were performed by cutting.

[Problem that the invention seeks to solve]

In the heading method, which is the first manufacturing method, a ready-made hollow pipe (31) is used.
) was cut into a predetermined size and the thickness of the blank (34) was a problem. That is, as shown in FIG. 5, when assembling the LJI air pipe (33), the January air pipe (33)
) is to be caulked to seal the leg (20), and this caulking work is greatly affected by the wall thickness of the leg (20), increasing the caulking load.
) The caulking load would be concentrated at one point in the caulking area, resulting in 1F4 scratches at the caulking area, resulting in a situation where airtightness could not be obtained. Further, since the wall thickness of the leg portion (20) is not constant, the thickness of the caulking tube place is not constant, which makes it difficult to produce a stable product, which has caused problems.

Therefore, it has been required that the leg portions (20) have an appropriate thickness.

However, by using a hollow pipe (31) with a wall thickness that satisfies the conditions for caulking the legs, the blank (34) is finished into a finishing molding die (41) as shown in FIG. 3(D). When the head (19) is pushed in using the molding sleeve (42) and at the same time the head (19) is subjected to a final tube expansion process using the final molding pin (43), the wall thickness of the bottom surface (32) of the head (19) becomes thinner. , Cracks, etc. had occurred on the bottom surface of the head (19). In this way, in order to manufacture a blank (34) with a wall thickness that is suitable for caulking the leg portion (20) and expanding the head portion (19), the hollow pipe (31) is made into a ready-made product. It was very difficult to get from.

Next, in the second manufacturing method, which is the combination joining method, there is a problem that cracks occur in the hollow pipe (31) corresponding to the head part (19), which occurred in the case of the first manufacturing method, which was the forging method. However, since this second manufacturing method requires a high degree of precision in the welding process, the welding condition is inconsistent, and depending on the product, the joint condition may be poor and the airtightness may not be maintained. There were cases where the situation occurred.

Furthermore, the cutting method d3, which is the third manufacturing method, has the problem that it takes a lot of manufacturing time and results in a product that is too expensive.

In any case, in order to produce a product with stable precision using any of the first, second, and third manufacturing methods,
There were many problems such as unstable quality and multiple problems in the process.

[Means for solving problems]

The present invention was invented with the aim of solving these problems and providing products with stable performance to large groups. A blank (6) is manufactured by applying edge finishing to the cut material (2), which has been cut to
A stepped hollow pipe (18
), and then the stepped hollow pipe (18)
The head (19) part and the leg part (20
), and again form the stepped hollow pipe (1
The head part (19) of 8) is subjected to preliminary pipe expansion, and the leg part (20) is extended to a predetermined length, and finally, the head part of the step A/1 hollow pipe ('18) is After the preliminary tube expansion in section (19), finish tube expansion is carried out.
It was rated Aa.

[Effect]

A blank (6) is manufactured from a bar material, and a recessed hole (12) in the head part (19) is inserted into the blank (6) in advance.
The diameter of the hollow hole (10) in the leg part (20) is slightly larger than that in the head part (19) and the leg part (20).
) A stepped hollow pipe (18) having appropriate wall thicknesses is obtained, and in the subsequent forging process, the wall thicknesses of the head (19) and leg parts (20) are made constant. Adjustment is possible, and as a result, when assembling the exhaust pipe, the leg portion (20) can withstand the caulking load and has a wall thickness that is 1 thicker, preventing damage to the caulking area, maintaining airtightness, and, on the other hand, The bottom surface (32) of the head (19)
) has sufficient wall thickness, so the head (19)
When preliminary tube expansion is performed on the section, cracks no longer occur on the bottom surface (32) of the head (19).

Moreover, from the cutting of the bar (1) to the predetermined exhaust pipe (33
)ki (E
This resulted in a series of assembly lines at JI, making it possible to provide products with stable performance to Otsumi.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In Fig. 1 (A>), (1) is a bar, and in a multi-stage heading machine, the bar (1) is cut to a predetermined size, and the first
As shown in FIG. ), and as shown in FIG.
If you press the die (3) with the second punch (5), the same ■
4, a blank (6) is manufactured by pressing the front end surface of the cut material (2) to form a concave surface.

Next, as shown in FIG. 1(D), the blank (6)
At the same time, press the second die (7) into the first sleeve (8), and at the same time make a hollow hole (1) described later on the front end surface of the blank (6).
0) Connect the recessed hole (12) with the larger diameter to the first pin (9).
), and at the same time, as shown in FIG. A second hollow hole (10) is formed on the rear end surface of the blank (6).
The blank (6) is formed by a pin (11), and then the blank (6) is inverted as shown in FIG.
is pushed into the third die (21) by the third sleeve (14) from the side with the recessed hole (12), and at the same time both bottom surfaces between the recessed hole (12) and the hollow hole (10) of the blank (6) Pass through the third pin (17) at (15, 16) and connect the hollow pipe (18) with stage A1.

After that, as shown in FIG.
) into the fourth die (22) having a shape corresponding to the leg (20) following the fourth sleeve (23), and at the same time penetrate the fourth pin (24) into the stepped hollow pipe (18). Then, the head part (19) and the leg part (20) are formed by the forward extrusion method 1, and then, as shown in FIG.
As shown in , at the same time the stepped hollow pipe (18) is pushed into the fifth die (25) using the fifth sleeve (2G), the fifth pin (21) is inserted into the head part (19). Through, the head (19) part is subjected to preliminary expansion processing, and
The leg portion (20) is extended to a predetermined length, and finally, as shown in FIG. At the same time, push the 6th pin (30) through the head (19) and perform a final expansion process on the part of the head (19) that has undergone the preliminary expansion process, not shown in Figure 2. Exhaust pipe (33
) manufacturing cover.

In the above manufacturing method, a blank (6) is manufactured from a bar material, and the head (19) of the blank (6) is prepared in advance.
The diameter of the hollow hole (10) in the part of the head (10) is slightly larger than that of the hollow hole (10) in the leg part (20).
A stepped hollow pipe (18) having appropriate wall thicknesses in the section 9) and the leg section (20) is obtained, and in the subsequent heading process, the head section (19) and the leg section (20) are It is now possible to adjust the thickness of each to be constant.

As a result, when assembling the exhaust pipe (33), the legs (
20) The head (19) withstands the caulking load and has a wall thickness of
Since the wall thickness of the bottom surface (32) of is sufficiently thick,
When performing preliminary tube expansion on the head (19), the head (19)
19) No more cracking occurred on the bottom surface (32). Moreover, the process from producing the rod+A (1) to the specified exhaust pipe (33) is a series of assembly operations performed by a single multi-stage heading machine, making it possible to provide products with stable performance to Otsu. It has become possible.

[Effects of the Invention] As explained above, the present invention involves producing a blank by cutting a bar material into a predetermined size and subjecting it to an end finishing process in a multi-stage heading machine, and then , Processing is performed on both end faces of the blank to produce a stage f+1 hollow pipe, and then a head part and a leg part are formed by forward extrusion of the stage 1 and 1 hollow pipe. And again,
The head part of the stepped hollow pipe is subjected to a preliminary expansion process, and the legs (20) are extended to a predetermined length, and finally, the head part of the stepped hollow pipe is expanded. Since the tube was manufactured by performing a finishing tube expansion process on the part after the tube expansion process, a blank was manufactured from a bar material, and the concave hole in the head part of the blank was inserted from the hollow hole in the leg part. A stepped hollow pipe with a slightly larger diameter and appropriate wall thickness in the head and leg parts is obtained,
During the subsequent heading process, it is now possible to adjust the wall thickness of the head and legs to be constant.

As a result, when assembling the exhaust pipe, the wall is thick enough to withstand the caulking load on the legs, preventing puncture wounds at the caulking points and maintaining airtightness, while the bottom of the head is thick enough to withstand the caulking load. Because of its thickness, when pre-expanding the head part, cracks will not occur at the bottom of the head, and the process from manufacturing the bar material to the specified exhaust pipe is easy. One multi-stage pressure j? It becomes a series of production work in i□, and has the effect of being able to provide products with stable performance to large groups.

[Brief explanation of the drawing]

Figure 1 (A) (B) (C)' (D) (E) (F) (G)
(+-1) and N) are process diagrams showing the manufacturing method of the exhaust pipe to be applied to the electromagnetic wave generating device of the present invention. Figure 3 (A) (B
)(C) and (D> are process diagrams showing a conventional forging method, FIG. 4 shows a conventional assembly and welding method, and FIG. 5 shows a leg part when assembling an exhaust pipe. It is a figure which shows the caulking state.

Claims (1)

[Claims] In a multi-stage heading machine, a cut material (2) obtained by cutting a bar material (1) into a predetermined size is placed in a first die (3) with a first punch (4).
), at the same time press the rear end surface of the cut material (2) to press the surface, and also invert the cut material (2) and transfer the cut material (2) to the first die (3) and the second die. Punch (5
) to produce a blank (6) having a concave surface by pressing the front end surface of the cutting material (2), and then inserting the blank (6) into a second die (7) into a first sleeve ( 8), at the same time, a recessed hole (1
2) is formed by the first pin (9), and the blank (6) is inverted, and the blank (6) is formed by the second die (7).
) with the second sleeve (13), and at the same time insert the hollow hole (10) into the rear end surface of the blank (6) with the second pin (1
1), and further, the blank (6) is inverted, and the blank (6) is pushed into the third die (21) by the third sleeve (14) from the side having the recessed hole (12), and at the same time, the blank ( 6) recessed hole (12) and hollow hole (10
), a third pin (17) is passed through the bottom surfaces (15, 16) between the two bottom surfaces (15, 16) to produce a stepped hollow pipe (18), and then the stepped hollow pipe (18) is fitted with a head at the front. Part (19)
A fourth sleeve (23) is attached to a fourth die (22) having a shape corresponding to the leg portion (20) following the head portion (19).
At the same time, the fourth pin (24) is penetrated into the stepped hollow pipe (18), and the head (1) is pushed in by the forward extrusion method.
9) and the leg portion (20), and again push the stepped hollow pipe (18) into the fifth die (25) with the fifth sleeve (26), and at the same time press the head portion ( 19
), pass through the fifth pin (21), pre-expand the head (19) part, extend the leg part (20) to a predetermined length, and finally Hollow pipe (1
8) into the sixth die (28) through the sixth sleeve (29), and at the same time insert the sixth pin (3) into the head (19).
A method for manufacturing an exhaust pipe for an electromagnetic wave generator, characterized in that the exhaust pipe for an electromagnetic wave generator is passed through the head (19) and subjected to a final expansion process on the portion of the head (19) after the preliminary expansion process.