JP4942616B2 - Hermetic compressor and method for producing tubular shell for hermetic compressor - Google Patents

Description

  The present invention relates to a hermetic compressor and a method for producing a tubular shell for a hermetic compressor, in particular, a method for producing a tubular shell for a hermetic compressor that seals a high-pressure refrigerant, and a hermetic seal produced by the production method. The present invention relates to a hermetic compressor including a tubular shell for a mold compressor.

A conventional hermetic compressor includes a compressor main body that stores a refrigerant compression means and a liquid reservoir that communicates with the compressor main body. The compressor main body closes both the tubular shell and both ends of the tubular shell. It has an upper shell and a bottom shell. Tubular shells are shaped like a sheared or slitter-cut rectangular plate into a tubular shape, joined together with a shear surface that is sheared by shearing or slitter cut, and no weld bead on the back side (same as the tubular inner surface). It is manufactured by plasma welding under such conditions.
Further, in a hermetic compressor using a refrigerant gas such as carbon dioxide (CO ₂ ), the pressure of the refrigerant gas is high, so that it is necessary to increase the plate thickness of the tubular shell. Welding is essential. Therefore, a welding method is disclosed in which a good back bead is obtained in one-side welding of thick plate materials, and the number of multipasses is small and welding distortion hardly occurs (for example, see Patent Document 1).

Japanese Unexamined Patent Publication No. 2002-224836 (page 2-3, FIG. 1)

  However, in the invention disclosed in Patent Document 1, the groove shape is changed to a Y-shaped groove (first step), and the bottom of the V-shaped portion of the Y-shaped groove is sealed and welded using a plasma arc (second process). Step), plasma keyhole welding is performed on the root portion of the Y-shaped groove, and back welding is performed (third step), and multi-layer welding using a filler wire is performed on the V-shaped portion of the Y-shaped groove (first step). 4 steps), a thick plate single-sided welding method of titanium or a titanium alloy, and the application of this method to mild steel has the following problems. In multi-layer welding (fourth step), after-shielding with an inert gas is performed using plasma welding or TIG welding.

Therefore, the invention disclosed in Patent Document 1 has the following problems.
(A) Compared to SUS304 or the like, a mild steel having a low viscosity when melted and a large thermal conductivity has a problem that “burn-out” occurs when the heat input is increased. For this reason, stable welding cannot be performed with mild steel having a thickness exceeding 6 mm.
(Ii) Since the bottom of the V-shaped portion of the Y-shaped groove is closed by sealing welding (second step), when performing multiple deposition after back wave welding (fourth step), using plasma welding, “Tanning welding” that does not allow gas to penetrate, not only accelerates chip consumption, but also slows the welding speed, resulting in poor productivity.

(Iii) In TIG welding (4th step), the weld bead width is narrow, so waving and multi-pitching are indispensable, and undercuts caused by plasma welding (third step) are covered if waving and multi-pitching are not performed. Not only can the welding speed be slow.
(E) In thick plate welding, it is possible to stably form a bead on the back side, that is, to let gas tightly penetrate and not melt the molten metal, leading to stable quality. When the protrusion is formed, it hinders the tube expansion process for improving the inner diameter accuracy, and there is a problem in incorporating a device (a driving element such as a compression element or a motor) disposed inside the tubular shell.

  The present invention has been made to solve the above-described problems, and is for a hermetic compressor that has a stable weld bead and can be used in a hermetic compressor that uses a high internal pressure refrigerant. A method for manufacturing a tubular shell, and a hermetic compressor having a tubular shell for a hermetic compressor manufactured by the manufacturing method are provided.

A method for producing a tubular shell for a hermetic compressor according to the present invention includes a tubular tubular shell, an upper shell and a bottom shell that respectively close both ends of the tubular shell, and a compression housed in the tubular shell. A method of producing a tubular shell for a hermetic compressor in a hermetic compressor having a mechanism and an electric motor that drives the compression mechanism,
A first step of processing both side edges of the rectangular material so as to form a Y-shaped groove when the both side edges are contacted;
A second step in which the V-shaped portion of the Y-shaped groove is formed into a substantially cylindrical shape so as to be an outer periphery;
A third step of pressing the molded substantially cylindrical body in a mold to reduce the diameter;
A fourth step of keyhole welding the root portion of the Y-shaped groove;
A fifth step of overlay welding the V-shaped portion of the Y-shaped groove ;
Having.

The hermetic compressor according to the present invention includes a tubular tubular shell, an upper shell and a bottom shell that respectively close both ends of the tubular shell, a compression mechanism housed in the tubular shell, and the compression mechanism. A hermetic compressor having an electric motor for driving
The tubular shell is produced by a method for producing the tubular shell for a hermetic compressor.

In the method for manufacturing a tubular shell for a hermetic compressor according to the present invention, stable plasma welding can be performed by reducing the substantial plate thickness when plasma welding is performed by using a Y-shaped groove. In addition, for the undercut portion due to the Y-shaped groove, build-up welding is required to secure the pressure resistance of the tubular shell for a hermetic compressor, but MAG welding M can be performed under a single welding. Since the cut portion can be built up and the processing speed is fast, the productivity is high.
In addition, the hermetic compressor according to the present invention produces an effect of high welding reliability because the tubular shell constituting the hermetic compressor is manufactured by the method of manufacturing the tubular shell for the hermetic compressor according to the present invention. .

[Embodiment 1: Hermetic compressor]
FIG. 1 is a side sectional view schematically showing the configuration of a hermetic compressor according to Embodiment 1 of the present invention. In FIG. 1, a hermetic compressor (hereinafter referred to as “compressor”) 100 includes a compressor main body 1 and a reservoir container 2 provided on the inlet side of the compressor main body 1.
The compressor body 1 includes a tubular shell 1c, an upper shell 1e and a bottom shell 1f that respectively close both ends of the tubular shell 1c, a compression mechanism 1a housed in the tubular shell 1c, and an electric motor 1b that drives the compression mechanism 1a. And have. At this time, a suction pipe 1g communicating with the liquid reservoir 2 is connected to the side surface of the tubular shell 1c, and a discharge pipe 1d is installed in the upper shell 1e.

And the tubular shell 1c is manufactured by the manufacturing method of the tubular shell for closed type compressors which concerns on this invention demonstrated in Embodiment 2 mentioned later.
The compressor 100 is used as, for example, a hot water compressor, and uses a refrigerant gas such as carbon dioxide (CO ₂ ), so that the design pressure of the tubular shell 1c is used for air conditioning. Nearly four times the design pressure (4 MPa or less) in the R-410A refrigerant, a plate thickness of 6 mm or more is required.

[Embodiment 2: Manufacturing method of tubular shell for hermetic compressor]
2 to 5 are a plan view and a perspective view schematically showing a method for manufacturing a tubular shell for a hermetic compressor according to Embodiment 2 of the present invention, following the steps.

  (1st process) When the material 3 cut | disconnected by the slitter process or the shearing process to the predetermined dimension is shape | molded later, "a Y-shaped groove | channel" is processed into the both-sides edge which the material 3 opposes (FIG. 2). (See (a)). At this time, the length of the root portion of the groove is desirably 5 mm or less, and the groove width when the end portions are butted is desirably 8 mm or less.

  (Second step) Roll-molding into a substantially cylindrical body (exactly, a partially open cylindrical shape) 4 so that the Y-shaped groove spreading side (same as the V-shaped portion) becomes the outer periphery (see FIG. 2 (b)). In the drawing, roll bending using three bending rolls 11, 12b, 12c (collectively referred to as “roll bending apparatus 10”) is shown, but the present invention is not intended to limit the manner of molding. For example, press bending may be used.

  (Third Step) The substantially cylindrical body 4 is divided into a lower mold 21 and an upper mold 22 in which a pair of semicircular (exactly not geometrical semicircular arcs) calibers are formed (collectively, “mold 20 To reduce the diameter (see (c) of FIG. 2). For convenience of explanation, the substantially cylindrical body 4 having a reduced diameter (having improved dimensional accuracy) is referred to as a cylindrical body 5.

  (4th process) The seam welding which turns the butted part of the cylindrical body 5 into keyhole welding K and a back bead comes out by plasma welding (refer (a) and (b) of FIG. 3). At this time, although the cylindrical body 5 is restrained by the tunnel-type pressing jig 30, the present invention does not limit the fixing method to this.

(Fifth step) Overlay welding is performed by MAG (Metal Active Gas) welding M. When plasma welding is performed with the Y groove specification, the thickness becomes insufficient, and the welded portion is recessed, so that overlay welding is performed to ensure pressure resistance (see FIGS. 4A and 4B).
When the groove width is 8 mm, the width of the recessed portion of the welded portion is about 10 to 12 mm. By MAG welding M, overlay welding with a width of about 13 mm is required. Therefore, in order to complete the overlay welding by the MAG welding M in one time, the groove width is desirably 8 mm or less. Further, it is desirable that the welding direction is opposite to the welding direction in plasma welding.

  (Sixth step) The back bead is removed (see FIGS. 5A and 5B). Although it is desirable to remove the back bead efficiently using the milling blade 40, it is also possible to remove it by a key theta method. However, the welded portion is more distorted than the other portions and is processed linearly, and if all the back bead projections are to be removed, the cutting width near the center of the tubular shell increases. In this case, the build-up bead width by MAG welding M is exceeded, and there is a possibility that a portion where the design plate thickness cannot be secured may occur. Therefore, it is desirable to perform program processing utilizing shape measurement data.

(Seventh step) The poor weld portion is cut out (not shown).
(Eighth step) The tube is expanded by an expander (not limited to a model) having a plurality of pieces 50 that move by a distance equal to the radial direction to ensure the inner diameter accuracy (see FIG. 6).
Any of the seventh step and the eighth step may be performed first. Moreover, when the poor welding part does not occur or when the inner diameter accuracy is already secured, the seventh step and the eighth step can be omitted.

As described above, according to the present invention, since the butted portion of the cylindrical body 5 constrained by the holding jig 30 is keyhole welded by plasma welding (S4), the root portion of the Y-shaped groove is in close contact. Therefore, there is no need to temporarily fix (temporary welding) the root portion.
In addition, when the root portion is temporarily fixed (see Patent Document 1), if a filler is inserted by temporary fixing, a bead is partially generated and keyhole welding may not be successful. On the other hand, in the present invention, since the keyhole welding by plasma is performed without holding the tubular body 5 while temporarily holding it, there is no problem of bead cracking or the like of the temporarily welding regardless of whether or not the filler is charged. .

Furthermore, the build-up welding (S5) is to the extent that an alloy phase is formed on the bead surface of plasma welding while supplying filler by MAG welding (not to penetrate), so that the bead of plasma welding is cracked. There is no.
In addition, since MAG welding has a wider welding width than TIG welding, it is possible to cover the dent formed in the preceding keyhole welding by one build-up welding.

[Example]
FIGS. 7 to 9 are welds in an example of a method for manufacturing a tubular shell for a hermetic compressor according to Embodiment 2 of the present invention, in which (a) is a side view seen from the outside, and (b) is FIG. It is sectional drawing. In the example, a tubular shell was manufactured from a mild steel material having a thickness of 6 mm. At this time, the chamfered portion C3 of the Y groove has a width of 6 mm and a route length of 3 mm. At the time of roll bending, unevenness is provided on the surface of the roll as slip prevention. In particular, the unevenness is transferred to the end of the roll.
In the conventional slitter cut surface, unevenness affects the gas penetration during welding, which may affect the welding quality, but in the case of the Y-shaped groove of the present invention, the slitter cut surface is closer to the weld center. There was no effect because it was off.
When the welding speed is 250 mm / min, the dent width of the front bead is about 8 to 10 mm, and the overlay welding width is about 12 mm.

  As shown in FIGS. 7A and 7B, when plasma welding is performed, the start portion Sp becomes “tanning welding” that does not allow gas to penetrate, and the end portion Ep is recessed.

On the other hand, as shown in FIGS. 8A and 8B, when the welding direction of MAG welding is welded in the same direction as the plasma welding direction, the start portion Sm is weakly welded and the end portion Em is plasma welded. Can not cover the dent due to. For this reason, both ends become poorly welded parts, and a considerable range must be removed, resulting in poor material yield.
In the figure, the broken line represents the bead appearance K of the plasma welding in the previous process, the solid line represents the bead appearance m generated by MAG welding, and the black circle F represents the trace of the weld filler missing in the MAG welding end treatment. It is always shown when welding.

  Therefore, as shown in FIGS. 9A and 9B, welding is performed so that the welding directions are opposite to each other, so that the dent portion of the plasma welding end portion Ep is left behind in the MAG welding M start process. There is a high possibility that the start portion Sp can be used in the end processing of the MAG welding M. That is, the unusable range hatched with a horizontal line in the figure is reduced.

As a result, according to the present invention, the length of defective welding can be reduced, and the material yield can be improved.
Overlay welding is performed for the purpose of ensuring strength, but it also serves to suppress the occurrence of leakage defects due to pinholes that may occur in plasma welding, and is the aspect of ensuring leakage quality (same as ensuring non-leakage quality). But it is effective.
In addition, the back bead was removed using a milling blade, and the cutting width was kept below the dent width by plasma welding. By doing so, a plate thickness of 6 mm could be secured over the entire circumference.

  From the above, the method for producing a tubular shell for a hermetic compressor according to the present invention is excellent in welding quality and the material yield is improved, so that it can be widely used as a method for producing tubular shells for hermetic compressors of various shapes. Can do. Further, the hermetic compressor of the present invention is excellent in the welding quality of the tubular shell for the hermetic compressor constituting the hermetic compressor, and thus has high reliability and can be widely used as various hermetic compressors.

Sectional drawing which shows typically the structure of the hermetic type compressor which concerns on Embodiment 1 of invention. The top view which shows typically the manufacturing method of the tubular shell for closed type compressors which concerns on Embodiment 2 of this invention later on in process. The perspective view which shows the process following FIG. 2 typically. FIG. 4 is a perspective view schematically showing a process following FIG. 3. The perspective view which shows the process following FIG. 4 typically. FIG. 6 is a perspective view schematically showing a process following FIG. 5. The external view and sectional drawing which looked at the welding part in the Example of the manufacturing method of the tubular shell for sealed type compressors concerning Embodiment 2 of this invention from the outer side. The external view and sectional drawing which looked at the welding part in the Example of the manufacturing method of the tubular shell for sealed type compressors concerning Embodiment 2 of this invention from the outer side. The external view and sectional drawing which looked at the welding part in the Example of the manufacturing method of the tubular shell for sealed type compressors concerning Embodiment 2 of this invention from the outer side.

Explanation of symbols

  1: compressor body, 1a: compression mechanism, 1b: electric motor, 1c: tubular shell, 1d: discharge pipe, 1e: upper shell, 1f: bottom shell, 1g: suction pipe, 2: reservoir tank, 3: material, 4: substantially cylindrical body, 5: cylindrical body, 10: roll bending apparatus, 11: bending roll, 12b: bending roll, 12c: bending roll, 20: mold, 21: lower mold, 22: upper mold, 30 : Pressing jig, 40: milling blade, 50: piece (expander), 100: compressor, C3: chamfered part, Ep: end part (plasma welding), Em: end part (MAG welding), F: welding filler Traces, K: Keyhole welding, M: MAG welding, Sp: Start part (plasma welding), Sm: Start part (MAG welding).

Claims (11)

A hermetic compressor having a tubular tubular shell, an upper shell and a bottom shell that respectively close both ends of the tubular shell, a compression mechanism housed in the tubular shell, and an electric motor that drives the compression mechanism A method for producing a tubular shell for a hermetic compressor in
A first step of processing both side edges of the rectangular material so as to form a Y-shaped groove when the both side edges are contacted;
A second step in which the V-shaped portion of the Y-shaped groove is formed into a substantially cylindrical shape so as to be an outer periphery;
A third step of pressing the molded substantially cylindrical body in a mold to reduce the diameter;
A fourth step of keyhole welding the root portion of the Y-shaped groove;
A fifth step of overlay welding the V-shaped portion of the Y-shaped groove ;
A method for producing a tubular shell for a hermetic compressor, comprising:   2. The tubular shell for a hermetic compressor according to claim 1, wherein the opening width of the V-shaped portion of the Y-shaped groove is 8 mm or less, and the length of the root portion of the Y-shaped groove is 5 mm or less. Pipe making method. The method for producing a tubular shell for a hermetic compressor according to claim 1 or 2, further comprising a sixth step of removing the back bead formed in the fourth step . 4. The tubular shell for a hermetic compressor according to claim 3, wherein a processing width for removing the back bead in the sixth step is equal to or less than a build-up welding width by build-up welding in the fifth step. Method. 3. The method for producing a tubular shell for a hermetic compressor according to claim 1, wherein the fourth step is plasma welding using a non-consumable electrode . 5. The method for producing a tubular shell for a hermetic compressor according to claim 1, wherein the fifth step is MAG (Metal Active Gas) welding . The start position and the end position of overlay welding in the fifth step are approximately matched with the end position and start position of the keyhole welding in the fourth step, respectively. For producing a tubular shell for a hermetic compressor. The method for producing a tubular shell for a hermetic compressor according to any one of claims 1 to 7, further comprising a step of cutting out the defective weld portion generated in the fifth step . The method for producing a tubular shell for a hermetic compressor according to any one of claims 1 to 8, further comprising a step of expanding the tube with an expander after the fifth step .   A hermetic compressor having a tubular tubular shell, an upper shell and a bottom shell that respectively close both ends of the tubular shell, a compression mechanism housed in the tubular shell, and an electric motor that drives the compression mechanism Because
  A hermetic compressor, wherein the tubular shell is produced by the method for producing a tubular shell for a hermetic compressor according to any one of claims 1 to 9.   The hermetic compressor according to claim 10, wherein carbon dioxide refrigerant is used.

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