JP2011085143A - Welding method of compressor, and compressor weld by using the welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding method of a compressor, suppressing a displacement amount of a component fixed to the inside of a casing, in welding of a casing body part with a casing cover of the compressor. <P>SOLUTION: The casing 2 of the compressor 1 is a sealed vessel including: a tubular casing body part 21; a casing upper cover 22 sealing an upper end of the casing body part 21; and a casing lower cover 23 sealing a lower end of the casing body part 21. Two welding torches 51, 52 are disposed at intervals at 180° of a center angle with respect to a center axis B of the casing body part 21. Tips of welding torches 51, 52 are set while facing an outer end part of an area 30 to be joined. An upper bearing housing 6 is put on an end face 21b of the casing body part 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a welding method for a compressor, and more particularly to a welding method for sealing a joint portion between a casing body of a compressor and a casing cover.

  The casing of the compressor forms a sealed space by welding a cylindrical casing body and a casing cover that closes the opening end of the casing body. As for the welding method, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2003-33872), a casing cover is press-fitted and overlapped inside or outside the opening end of the casing body, and the overlapping joining is performed. In this method, one welding torch is made to face the target region, the casing body is rotated, and the joining target region is welded.

  For example, as shown in FIG. 5, when the welding target region between the casing body 121 and the casing upper cover 122 is welded using one welding torch 151, the temperature of the welding target portion is from the start of welding to the end of welding. There is a possibility that the distribution is non-uniform, the displacement difference due to thermal expansion between the heat input portion and the non-heat input portion is large, the bearing 106 fixed in the container is inclined, and the amount of misalignment of the shaft 105 is increased.

  The subject of this invention is providing the welding method of the compressor which suppresses the positional offset amount of the components currently fixed in the casing at the time of welding with the casing trunk | drum and casing cover of a compressor.

  A compressor welding method according to a first aspect of the present invention is a compressor welding method including a casing in which a first casing member having an opening formed at an end thereof and a second casing member covering the opening are joined. It is. The casing houses a compression unit, a drive shaft that transmits power of the drive unit to the compression unit, and a bearing unit that supports the drive shaft. The bearing portion is positioned by placing a part of the bearing portion on the end surface of the first casing member. The first casing member and the second casing member are a plurality of welding torches arranged in an annular joining target region formed by the first casing member and the second casing member at equal intervals along the joining target region. It is joined by welding all around.

  With this compressor welding method, the temperature difference between the point closest to the welding torch and the point farthest from the welding torch is reduced, and the temperature distribution of the entire joining target region is stabilized. As a result, the entire joining target area expands evenly, and the positional deviation of the components positioned inside the casing is suppressed to a small level. Further, since the entire end face supporting the bearing is displaced almost uniformly by the heat quantity from the plurality of welding torches, the amount of misalignment of the bearing due to welding can be kept small.

  A compressor welding method according to a second aspect of the present invention is a compressor welding method including a casing in which a first casing member having an opening formed at an end and a second casing member covering the opening are joined. It is. A 1st casing member and a 2nd casing member are the some welding torch arrange | positioned at equal intervals along the joining object area | region in the cyclic | annular joining object area | region formed with a 1st casing member and a 2nd casing member It is joined by welding all around. The welding torch is a welding torch for arc welding supplied with electric power from a welding power source. The amount of heat input from the welding torch to the joining target region during welding is managed by an integrated value of the current and voltage input from the welding power source to the welding torch. The average variation width of the integrated value is 50% or less of the intermediate value between the allowable maximum value and the allowable minimum value of the integrated value.

  With this compressor welding method, the temperature difference between the point closest to the welding torch and the point farthest from the welding torch is reduced, and the temperature distribution of the entire joining target region is stabilized. As a result, the entire joining target area expands evenly, and the positional deviation of the components positioned inside the casing is suppressed to a small level. Also, by managing the average variation width of the integrated value, for example, for bearings in the casing, even if the maximum misalignment amount of the bearing calculated from the variation of equipment and parts is added, the misalignment amount is within the allowable range. Fits in.

  The compressor welding method according to the third aspect of the present invention is the compressor welding method according to the first aspect or the second aspect, and includes three or more welding torches.

  In this compressor welding method, the temperature distribution at the time of welding is further stabilized, and the positional deviation amount of the internal parts after welding can be further reduced.

  The compressor concerning the 4th viewpoint of the present invention is welded using the welding method of the compressor concerning any one of the 1st viewpoint to the 3rd viewpoint.

  In this compressor, since the positional deviation after welding of the internal components positioned in the casing is suppressed, the performance of the compressor is improved.

  In the compressor welding method according to the first aspect of the present invention, the entire end face supporting the bearing is displaced almost evenly by the amount of heat from the plurality of welding torches, so that the misalignment of the bearing due to welding can be kept small.

  In the compressor welding method according to the second aspect of the present invention, by managing the average variation width of the integrated value, for example, in the bearing in the casing, the maximum misalignment amount of the bearing calculated from the variation of equipment and parts. Even if is added, the misalignment amount falls within the allowable range.

  In the compressor welding method according to the third aspect of the present invention, the temperature distribution during welding is further stabilized, and the amount of displacement of the internal components after welding is further reduced.

  In the compressor according to the fourth aspect of the present invention, the displacement of the internal parts positioned in the casing after welding is suppressed to be small, so that the performance of the compressor is improved.

The longitudinal cross-sectional view of a compressor. The enlarged view of the A section of FIG. The fragmentary sectional view of the compressor containing the position of a welding torch. The graph which shows the misalignment ratio of the bearing with respect to the input variation width of a welding torch. Schematic diagram of conventional welding methods

  Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are specific examples of the present invention and do not limit the technical scope of the present invention.

<Compressor configuration>
1 is a longitudinal sectional view of the compressor, and FIG. 2 is an enlarged view of a portion A in FIG. In FIG. 1, a compressor 1 is a compressor that compresses a compression medium such as a gas refrigerant. The compressor 1 supports a casing 2, a compression unit 3, a motor 4, a shaft 5 connected to a rotor 18 of the motor 4, an upper bearing housing 6 that supports the upper end of the shaft 5, and a lower end of the shaft 5. And a lower bearing housing 7.

  The casing 2 is a sealed container including a cylindrical casing body 21, a casing upper cover 22 that seals the upper end of the casing body 21, and a casing lower cover 23 that seals the lower end of the casing body 21. . Further, on the side surface of the casing 2, a suction port 2 a for sucking the compressed medium from the outside is formed at a position below the motor 4, and further, the compressed medium after compression is sent to the outside at a position above the compression unit 3. A discharge port 2b for discharging is formed. An oil sump 23a for accumulating lubricating oil is formed at the bottom inside the casing 2.

  The compression unit 3 is a mechanism for compressing the compression medium sucked into the casing 2 and includes a movable scroll 11 and a fixed scroll 12. The movable scroll 11 has an upward spiral protrusion 11a. The fixed scroll 12 has a downward spiral protrusion 12a. A gap between a portion where the spiral ridge portion 12a of the fixed scroll 12 and the spiral ridge portion 11a of the movable scroll 11 mesh with each other becomes a scroll compression chamber. The fixed scroll 12 is fixed to the inner wall of the casing 2 and the upper bearing housing 6.

  The motor 4 includes a stator 17 including electromagnetic coils and a rotor 18 including permanent magnets and laminated steel plates. The stator 17 is fixed to the casing body 21 of the casing 2 by spot welding or caulking. The stator 17 is also fixed to the upper bearing housing 6.

  A lubricating oil introduction passage 5 a is formed inside the shaft 5. During the rotation of the shaft 5, the inside of the lubricating oil introduction passage 5 a becomes negative pressure, so that the lubricating oil is sucked up from the oil reservoir 23 a of the casing lower cover 23, and the sliding portion of the compression portion 3, specifically, the movable scroll 11. The shaft portion and the sliding portion of the shaft 5 are supplied with oil.

  The upper bearing housing 6 has a columnar fixing portion 61 whose outer diameter is the same as or slightly smaller than the outer diameter of the casing body 21. In FIG. 2, the fixing portion 61 has an upper positioning surface 61a and a lower positioning surface 61b.

  When the upper bearing housing 6 is assembled into the opening 21 a of the casing body 21, the lower positioning surface 61 b is positioned by contacting the end surface 21 b of the casing body 21. When the casing upper cover 22 covers the opening 21a, the upper positioning surface 61a is pressed by the pressing surface 22a of the casing upper cover 22.

<Welding between casing and casing upper cover>
FIG. 3 is a partial cross-sectional view of the compressor including the position of the welding torch. In FIG. 3, a region 30 to be joined between the casing body 21 and the casing upper cover 22 extends from the lower positioning surface 61 b of the upper bearing housing 6 to the end surface 22 b of the casing upper cover 22.

  The two welding torches 51 and 52 are arranged at a central angle of 180 ° with respect to the central axis B of the casing body 21, and the tips of the welding torches 51 and 52 are at the outer end of the joining target region 30. It is installed facing up. Therefore, at the time of welding, welding is completed only by rotating the casing body 21 by 180 °. The number of welding torches is not limited to two. For example, when the number of welding torches is three, the number of welding torches is arranged at intervals of a central angle of 120 ° with respect to the central axis B of the casing body 21, and during welding. The welding is completed only by rotating the casing body 21 by 120 °.

  In the present embodiment, since the upper bearing housing 6 is placed on the end surface 21b of the casing body 21, the upper bearing housing 6 and the end surface 21b are displaced in a direction perpendicular to the end surface 21b by thermal expansion during welding. Here, when there is one welding torch, welding is performed in a state where the point closest to the welding torch is maximum displaced and the point farthest is minimally displaced, the upper bearing housing 6 is tilted and misalignment occurs. However, when the number of welding torches is two, the temperature difference between the closest point and the farthest point from the welding torch is small and the temperature distribution of the entire welding target area is stabilized, so the difference between the maximum displacement and the minimum displacement is reduced. The amount of misalignment of the upper bearing housing 6 can be kept small.

  However, when using a plurality of welding torches, the welding start point by one welding torch overlaps the welding end point by another welding torch, so that the welding start point and end point are conspicuous. In order not to impair the appearance, the number of welding torches is preferably 2 to 4.

<Welding torch input variation width and upper bearing housing misalignment ratio>
When using a plurality of welding torches, in order to stabilize the temperature distribution in the joining target region 30, it is necessary to manage the heat quantity input from the welding torch into the joining target region 30 within a certain range. However, since it is difficult to actually measure the amount of heat, in this embodiment, the average variation width of the integrated value of the current and voltage input from the welding power source to the welding torch is managed so as to be within a predetermined range. Has been.

  FIG. 4 is a graph showing a bearing misalignment ratio with respect to the input variation width of the welding torch. In the present embodiment, two welding torches 51 and 52 are used, and the misalignment amount ratio with respect to the input variation width is measured in advance to create the graph of FIG.

  In FIG. 4, the input variation width refers to the average variation width of the integrated value of the current and voltage input from the welding power source to the welding torch, with the intermediate value between the allowable maximum value and the allowable minimum value as a reference. It is a value expressed as a percentage value. The misalignment ratio is a value representing the misalignment as a percentage value with reference to the misalignment when the input variation is 0%.

  Even if the input variation width is 0%, misalignment with respect to the bearing span will always be about 1/1000 due to variations in assembly equipment accuracy and component accuracy, and the generally allowable maximum is The misalignment amount is 3/1000. Accordingly, even if misalignment occurs due to input variations during welding, the misalignment amount must be 3/1000 or less. Therefore, when the misalignment amount when the input variation is 0% is used as a reference, it is necessary to manage the misalignment amount ratio due to the input variation at 300% or less.

  As is apparent from FIG. 4, if the input variation width of the welding torch is 50% or less, the centering ratio of the bearing can be maintained at 300% or less.

<Features>
(1)
The casing 2 of the compressor 1 is sealed with a cylindrical casing body 21, a casing upper cover 22 that seals the upper end of the casing body 21, and a casing lower cover 23 that seals the lower end of the casing body 21. Container. The two welding torches 51 and 52 are arranged at a central angle of 180 ° with respect to the central axis B of the casing body 21, and the tips of the welding torches 51 and 52 are at the outer end of the joining target region 30. It is installed facing up. Therefore, at the time of welding, welding is completed only by rotating the casing body 21 by 180 °. Since the upper bearing housing 6 is placed on the end surface 21b of the casing body 21, the upper bearing housing 6 and the end surface 21b are displaced in a direction perpendicular to the end surface 21b by thermal expansion during welding. When the number of welding torches is two, the temperature difference between the closest point and the farthest point from the welding torch is small and the temperature distribution of the entire welding area is stable, so the difference between the maximum displacement and the minimum displacement is reduced, and the upper part The misalignment of the bearing housing 6 is suppressed.

(2)
In this compressor welding method, the number of welding torches is not limited to two. For example, when the number of welding torches is three, the central angle 120 ° with respect to the central axis B of the casing body 21. At the time of welding, welding is completed only by rotating the casing body 21 by 120 °. However, when using a plurality of welding torches, the welding start point by one welding torch overlaps the welding end point by another welding torch, so that the welding start point and end point are conspicuous. In order not to impair the appearance, the number of welding torches is preferably 2 to 4.

(3)
In the welding method of the compressor 1, the average variation width of the integrated value of the current and voltage input from the welding power source to the welding torch is managed so as to be within a predetermined range. If the input variation width of the welding torch is 50% or less, the centering ratio of the bearing can be maintained at 300% or less, which is the maximum allowable.

<Modification>
It is also possible to weld all the circumferences after performing temporary fastening welding at a plurality of locations before welding the entire area to be joined 30 of the casing body 21 and the casing upper cover 22.

  As described above, according to the present invention, since the positional deviation after welding of the internal parts positioned in the casing of the compressor is suppressed, the positional accuracy of the rotating body shaft and the bearing is strictly managed. Useful for scroll compressors and rotary compressors.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Casing 3 Compression part 5 Drive shaft 6 Bearing part 21 Casing trunk | drum (1st casing member)
21a Opening 21b End surface 22 Casing upper cover (second casing member)
30 welding target areas 51, 52 welding torch

JP 2003-33872 A

Claims (4)

A compressor welding method comprising a casing (2) in which a first casing member (21) having an opening (21a) at an end and a second casing member (22) covering the opening (21a) are joined. Because
The casing (2) houses a compression part (3), a drive shaft (5) for transmitting the power of the drive part to the compression part (3), and a bearing part (6) for supporting the drive shaft (5). And
The bearing (6) is positioned by placing a part thereof on the end surface (21b) of the first casing member (21),
The first casing member (21) and the second casing member (22) are annular joining target regions (30) formed by the first casing member (21) and the second casing member (22). Are joined by welding all around with a plurality of welding torches (51, 52) arranged at equal intervals along the joining target region (30).
Compressor welding method. A compressor welding method comprising a casing (2) in which a first casing member (21) having an opening (21a) at an end and a second casing member (22) covering the opening (21a) are joined. Because
The first casing member (21) and the second casing member (22) are annular joining target regions (30) formed by the first casing member (21) and the second casing member (22). Are welded by circumferential welding with a plurality of welding torches (51, 52) arranged at equal intervals along the joining target region (30),
The welding torch (51, 52) is a welding torch for arc welding supplied with electric power from a welding power source,
The amount of heat input from the welding torch (51, 52) to the joining target region (30) during welding is an integrated value of current and voltage input from the welding power source to the welding torch (51, 52). Managed,
The average variation width of the integrated value is 50% or less of an intermediate value between the allowable maximum value and the allowable minimum value of the integrated value.
Compressor welding method. 3 or more welding torches,
The compressor welding method according to claim 1 or 2. Welded using the compressor welding method according to any one of claims 1 to 3.
Compressor.

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