FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
WELDING DEVICE;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION
AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

2
DESCRIPTION

5 Technical Field
[0001]
The present disclosure relates to a welding device that welds a hermetic
container of a hermetic compressor applicable to a cooling and heating device, a
water heating device, or another device.
10 Background Art
[0002]
A hermetic container of a hermetic compressor includes a cylindrical hermeticcontainer body having upper and lower openings, a hermetic-container upper lid that
is fitted to an upper portion of the hermetic-container body, a hermetic-container lower
15 lid that is fitted to a lower portion of the hermetic-container body, and an installation
leg attached to the bottom surface of the hermetic-container lower lid.
[0003]
The hermetic container of this type is configured such that an upper fit portion
of the hermetic-container body and the hermetic-container upper lid, and a lower fit
20 portion of the hermetic-container body and the hermetic-container lower lid each are
welded by a welding device.
[0004]
For the welding device that welds the upper fit portion and the lower fit portion
of the hermetic container, for example, there is a technique in which the hermetic
25 container in a state where the hermetic-container upper lid and the hermetic-container
lower lid are fitted to the upper and lower portions of the hermetic-container body is
rotated by a rotary table, and the upper fit portion and the lower fit portion each are
simultaneously welded (for example, see Patent Literature 1). In Patent Literature 1,
by simultaneously welding each of the upper fit portion and the lower fit portion, it is
30 possible to assemble the hermetic container at low cost with high accuracy without a
3
change in posture such as inversion or lateral turning of the hermetic container at the
time of welding.
Citation List
Patent Literature
5 [0005]
Patent Literature 1: Japanese Unexamined Patent Application Publication No.
2004-162657
Summary of Invention
Technical Problem
10 [0006]
In the case of Patent Literature 1 described above, when the upper fit portion
and the lower fit portion are welded, the hermetic container is rotated by the rotary
table. Thus, there is a concern that slipping occurs between the hermetic-container
lower lid mounted on the rotary table and the hermetic-container body fitted onto the
15 hermetic-container lower lid, and that the hermetic-container body is inclined relative
to the hermetic-container lower lid. When the hermetic-container body is welded
while being inclined, there is a problem that the quality of the weld portions
deteriorates.
[0007]
20 The present disclosure is made to address the above-described problem, and
an object of the present disclosure is to provide a welding device capable of
simultaneously welding an upper fit portion and a lower fit portion of a hermeticcontainer body and obtaining weld portions of good quality by suppressing inclination
of the hermetic-container body during welding.
25 Solution to Problem
[0008]
A welding device of one embodiment of the present disclosure is a welding
device configured to arc-weld an upper fit portion and a lower fit portion of a hermetic
container constituted by fitting a hermetic-container upper lid and a hermetic30 container lower lid to upper and lower portions of a cylindrical hermetic-container
4
body having upper and lower openings. The welding device includes two welding
torches configured to perform arc welding; a turning mechanism configured to turn the
two welding torches in a circumferential direction of the hermetic-container body; and
a body holding mechanism configured to hold a portion of the hermetic-container
5 body of the hermetic container. The upper fit portion and the lower fit portion of the
hermetic-container body held by the body holding mechanism each are
simultaneously arc-welded while the turning mechanism turns the two welding torches
in the circumferential direction of the hermetic-container body.
Advantageous Effects of Invention
10 [0009]
With the one embodiment of the present disclosure, the upper fit portion and
the lower fit portion of the hermetic-container body can be simultaneously welded by
the turning mechanism turning the two welding torches in the circumferential direction
of the hermetic-container body. Moreover, since the body holding mechanism holds
15 the hermetic-container body during welding, inclination of the hermetic-container body
during welding is suppressed, and the weld portions of good quality can be obtained.
Brief Description of Drawings
[0010]
[Fig. 1] Fig. 1 is a schematic sectional view of a hermetic compressor that is a
20 welding target of a welding device according to Embodiment 1 of the present
disclosure.
[Fig. 2] Fig. 2 is an enlarged view of part surrounded by dotted line A in Fig. 1.
[Fig. 3] Fig. 3 is an enlarged view of part surrounded by dotted line B in Fig. 1.
[Fig. 4] Fig. 4 is a configuration diagram of the welding device according to
25 Embodiment 1 of the present disclosure.
[Fig. 5] Fig. 5 is an explanatory diagram of a positional relationship between a
welding wire and inclined surfaces of a lower fit portion in the welding device
according to Embodiment 1 of the present disclosure.
5
[Fig. 6] Fig. 6 is an explanatory diagram of a welding target position of the
welding wire in the welding device according to Embodiment 1 of the present
disclosure.
[Fig. 7] Fig. 7 is a process flow showing an operation of the welding device
5 according to Embodiment 1 of the present disclosure.
[Fig. 8] Fig. 8 is a schematic sectional view of a hermetic-container lower lid
held by an installation-leg holding mechanism of the welding device according to
Embodiment 1 of the present disclosure.
[Fig. 9] Fig. 9 illustrates the hermetic-container body that is conveyed by a
10 conveying robot of the welding device according to Embodiment 1 of the present
disclosure and that is in a state where a hermetic-container upper lid is fitted to an
upper opening.
[Fig. 10] Fig. 10 is a plan view in a state where the conveying robot clamps the
hermetic-container body in the welding device according to Embodiment 1 of the
15 present disclosure.
[Fig. 11] Fig. 11 is a plan view in a state where the conveying robot unclamps
the hermetic-container body and retracts in the welding device according to
Embodiment 1 of the present disclosure.
Description of Embodiments
20 [0011]
Hereinafter, a hermetic compressor including a hermetic container that is a
welding target will be described before description of a welding device according to
Embodiment 1 of the present disclosure.
[0012]
25 Embodiment 1
Fig. 1 is a schematic sectional view of a hermetic compressor that is a welding
target of a welding device according to Embodiment 1 of the present disclosure.
In Fig. 1, a hermetic container 2 of a hermetic compressor 1 includes a
cylindrical hermetic-container body 2a having upper and lower openings, a dish30 shaped hermetic-container upper lid 2b that is fitted to the upper opening of the
6
hermetic-container body 2a, and a dish-shaped hermetic-container lower lid 2c that is
fitted to the lower opening of the hermetic-container body 2a. An installation leg 2d
is attached to the bottom surface of the hermetic-container lower lid 2c. In the
hermetic container 2, when the hermetic-container body 2a is inclined relative to an
5 installation surface defined by the installation leg 2d, the inclination may cause
vibration and noise. Thus, the hermetic compressor 1 is used in a posture in which
the hermetic-container body 2a stands upright perpendicularly to the installation
surface.
[0013]
10 A compression mechanism 3 that compresses refrigerant and an electric motor
4 that drives the compression mechanism 3 are shrink-fitted into the hermeticcontainer body 2a. The electric motor 4 includes a rotor 4a and a stator 4b. The
rotor 4a is connected to a crankshaft 5 and transmits a rotational force from the
crankshaft 5 to the compression mechanism 3.
15 [0014]
In the above-described configuration, an attachment surface 6 of the
installation leg 2d for the hermetic-container lower lid 2c has a dish shape, and the
bottom surface of the hermetic-container lower lid 2c has a dish shape extending
along the attachment surface 6. Thus, the installation leg 2d is welded in a state
20 where the attachment surface 6 is in close contact with the bottom surface of the
hermetic-container lower lid 2c.
[0015]
Fig. 2 is an enlarged view of part surrounded by dotted line A in Fig. 1.
As illustrated in Fig. 2, inclined surfaces 10 having the same inclination angle
25 are formed at a lower portion of the hermetic-container body 2a and an opening end
portion of the hermetic-container lower lid 2c. The inclined surfaces 10 are inclined
surfaces inclined upward from the inner periphery toward the outer periphery of the
hermetic container 2, and have an inclination angle b (see Fig. 5 described later), for
example, in a range from 15 to 25 degrees. The inclined surfaces 10 are formed
30 over the entire circumferences of the hermetic-container body 2a and the hermetic-
7
container lower lid 2c. The hermetic-container body 2a and the hermetic-container
lower lid 2c are fitted to each other by being pressed and brought into close contact
with each other at the portion of the inclined surfaces 10.
[0016]
5 As described above, since the fit portion (hereinafter, referred to as a lower fit
portion 11) of the hermetic-container body 2a and the hermetic-container lower lid 2c
is provided by the inclined surfaces 10 having the same inclination angle from the
inner periphery toward the outer periphery of the hermetic container 2, the coaxiality
between the central axis of the hermetic-container body 2a and the central axis of the
10 hermetic-container lower lid 2c is secured while the fitting margins of the hermeticcontainer body 2a and the hermetic-container lower lid 2c are secured. Securing the
coaxiality can suppress vibration and noise of the hermetic compressor 1.
[0017]
Fig. 3 is an enlarged view of part surrounded by dotted line B in Fig. 1.
15 A protrusion 12 that regulates the insertion depth by which the hermeticcontainer upper lid 2b is inserted into the hermetic-container body 2a is formed on the
outer peripheral surface of the hermetic-container upper lid 2b. As illustrated in Fig.
3, the protrusion 12 is provided to protrude outward from the outer peripheral surface
of the hermetic-container upper lid 2b. The hermetic-container upper lid 2b is
20 inserted into the hermetic-container body 2a until the protrusion 12 comes into
contact with an upper end portion of the hermetic-container body 2a, and is fitted by
being pressed in this state. The attachment accuracy of the hermetic-container
upper lid 2b and the hermetic-container body 2a does not affect vibration and noise of
the hermetic compressor 1. Thus, not the inclined surfaces 10 described above but
25 the protrusion 12 is used for the fit portion (hereinafter, referred to as an upper fit
portion 13) of the hermetic-container upper lid 2b and the hermetic-container body 2a.
[0018]
The entire circumference of the lower fit portion 11 and the entire circumference
of the upper fit portion 13 of the hermetic container 2 are simultaneously welded by
30 arc welding with two welding torches of a welding device described below.
8
[0019]
Hereinafter, Embodiment 1 of the present disclosure will be described in detail
with reference to the accompanying drawings.
[0020]
5 Fig. 4 is a configuration diagram of the welding device according to
Embodiment 1 of the present disclosure. In Fig. 4, an x axis indicates a horizontal
direction, and a y axis indicates a vertical direction. Fig. 5 is an explanatory diagram
of a positional relationship between a welding wire and the inclined surfaces of the
lower fit portion in the welding device according to Embodiment 1 of the present
10 disclosure. Fig. 6 is an explanatory diagram of a welding target position of the
welding wire in the welding device according to Embodiment 1 of the present
disclosure.
[0021]
The welding device includes two welding torches 20a and 20b that performs
15 arc welding, a moving mechanism 30, a mount table 70, a lower-lid holding
mechanism 80, a conveying robot 90, and a controller 100.
[0022]
A workpiece to be handled by the welding device according to Embodiment 1 is
the hermetic container 2 described above. The lower fit portion 11 is welded with the
20 welding torch 20b, and the upper fit portion 13 is welded with the welding torch 20a.
[0023]
Hereinafter, each component constituting the welding device will be described.
[0024]
The welding torch 20a and the welding torch 20b feed welding wires 21 from
25 the tip ends thereof toward welding target positions and weld portions to be welded by
arc welding. When the lower fit portion 11 that is one of the weld portions according
to Embodiment 1 is welded, welding is performed while a target angle c of the welding
wire 21 is adjusted relative to an inclination angle b of the inclined surfaces 10 of the
lower fit portion 11 within the range of an adjustment margin d. In this case, the
9
target angle c is an angle defined by the welding wire 21 and the side surface of the
hermetic-container body 2a.
[0025]
The moving mechanism 30 is a mechanism that moves the welding torch 20a
5 and the welding torch 20b. The moving mechanism 30 includes a turning
mechanism 40, a transverse cylinder 50, and an individual adjustment mechanism 60.
[0026]
The turning mechanism 40 is a mechanism that turns the welding torch 20a
and the welding torch 20b in the circumferential direction of the hermetic-container
10 body 2a. The turning mechanism 40 includes one turning main shaft 41 that rotates
about the axis extending in the y-axis direction, one turning auxiliary shaft 42 provided
orthogonally to the turning main shaft 41, and a driving unit 43 that drives the turning
main shaft 41. The driving unit 43 includes a rotary motor 43a and a power
transmission mechanism (not illustrated) that transmit a rotational force to the turning
15 main shaft 41.
[0027]
The transverse cylinder 50 reciprocates the turning mechanism 40 in the x
direction. The transverse cylinder 50 is coupled to the driving unit 43, and moves
the turning main shaft 41 to a welding position (position illustrated in Fig. 1) at which
20 the turning main shaft 41 is positioned on a central axis O of the hermetic container 2,
and to an origin position set on the side of the minus direction of the x axis.
[0028]
The individual adjustment mechanism 60 is a mechanism that is coupled to the
turning auxiliary shaft 42 of the turning mechanism 40 and individually adjusts the
25 welding target position of each of the welding torch 20a and the welding torch 20b.
The individual adjustment mechanism 60 includes a first mechanism 61a that adjusts
the position of the welding torch 20a and a second mechanism 61b that adjusts the
position of the welding torch 20b. The first mechanism 61a and the second
mechanism 61b are independently operable.
30 [0029]
10
The first mechanism 61a includes an in-plane position adjustment mechanism
62 that adjusts the horizontal position x and the vertical position y relative to the
welding target position, and an angle adjustment mechanism 63 that adjusts the
target angle c relative to the welding target position. The second mechanism 61b
5 has the same configuration, and includes an in-plane position adjustment mechanism
62 and an angle adjustment mechanism 63.
[0030]
The in-plane position adjustment mechanism 62 is a mechanism that is
capable of moving a rod-shaped moving member 62a in the x direction and the y
10 direction relative to the turning auxiliary shaft 42. The angle adjustment mechanism
63 is a mechanism that rotatably supports a rod-shaped rotary member 63a coupled
to a lower end portion of the moving member 62a such that a distal end portion of the
rotary member 63a moves up and down. A welding torch is connected to the distal
end portion of the rotary member 63a, and the angle adjustment mechanism 63
15 adjusts the target angle c of the welding torch depending on the rotational position of
the rotary member 63a.
[0031]
In the first mechanism 61a and the second mechanism 61b having the abovedescribed configurations, the first mechanism 61a is coupled to axially inside of the
20 turning auxiliary shaft 42, and the second mechanism 61b is coupled to axially
outside of the turning auxiliary shaft 42. Then, the upper fit portion 13 is welded with
the welding torch 20a connected to the first mechanism 61a, and the lower fit portion
11 is welded with the welding torch 20b connected to the second mechanism 61b.
[0032]
25 The lower-lid holding mechanism 80 is a mechanism that is disposed on the
mount table 70 and that fixes and supports the workpiece. The lower-lid holding
mechanism 80 has a configuration in which three columns 82 extending in the y
direction are provided upright on a base 81 concentrically at different intervals, and
the columns 82 are passed through three through holes provided in the installation
30 leg 2d of the hermetic container 2 to hold the hermetic-container lower lid 2c.
11
[0033]
The conveying robot 90 includes a body holding mechanism 91 that holds the
hermetic-container body 2a at the distal end of the arm. The conveying robot 90
holds the hermetic-container body 2a with the body holding mechanism 91, and
5 conveys the hermetic-container body 2a from a device in the previous step onto the
lower-lid holding mechanism 80 of the welding device. The body holding mechanism
91 is constituted by a holding clamp that holds the hermetic-container body 2a such
that the periphery of the hermetic-container body 2a is sandwiched, and holds the
hermetic-container body 2a in a preset holding posture. The preset holding posture
10 is a posture based on the upper surface of the base 81 as a reference, and is a
posture in which the hermetic-container body 2a stands upright perpendicularly to the
installation surface of the installation leg 2d. The holding posture is recorded in
advance in an internal memory of the controller 100. Since the holding posture of
the hermetic-container body 2a is controlled as described above, it is possible to
15 secure the perpendicularity of the hermetic-container body 2a relative to the
installation leg 2d when the hermetic-container body 2a is conveyed by the conveying
robot 90 for fitting to the hermetic-container lower lid 2c. While the holding clamp is
used as the body holding mechanism 91 in this case, the body holding mechanism 91
is not limited to the holding clamp, and any mechanism that is capable of holding the
20 hermetic-container body 2a can be used.
[0034]
The controller 100 controls the entire welding device, and is constituted by, for
example, a microprocessor unit or another unit. The configuration of the controller
100 is not limited to the microprocessor unit. For example, the controller 100 may be
25 firmware, which is able to be updated. Alternatively, the controller 100 may be a
program module, and may be executed in response to a command from, for example,
a CPU (not illustrated).
[0035]
Fig. 7 is a process flow showing an operation of the welding device according
30 to Embodiment 1 of the present disclosure. Fig. 8 is a schematic sectional view of
12
the hermetic-container lower lid held by an installation-leg holding mechanism of the
welding device according to Embodiment 1 of the present disclosure. Fig. 9
illustrates the hermetic-container body that is conveyed by the conveying robot of the
welding device according to Embodiment 1 of the present disclosure and that is in a
5 state where the hermetic-container upper lid is fitted to the upper opening. Fig. 10 is
a plan view of a state where the conveying robot clamps the hermetic-container body
in the welding device according to Embodiment 1 of the present disclosure. Fig. 11
is a plan view in a state where the conveying robot unclamps the hermetic-container
body and retracts in the welding device according to Embodiment 1 of the present
10 disclosure.
[0036]
The hermetic-container lower lid 2c is carried into the welding device by a
conveying device (not illustrated), and is set to the lower-lid holding mechanism 80
(STEP 1). Then, as illustrated in Figs. 4 and 10, the body holding mechanism 91 of
15 the conveying robot 90 clamps the hermetic-container body 2a with the hermeticcontainer upper lid 2b fitted as illustrated in Fig. 9 (STEP 2). At this time, the body
holding mechanism 91 of the conveying robot 90 clamps a central portion of the
hermetic-container body 2a to stably hold the hermetic-container body 2a. The
conveying robot 90 conveys the hermetic-container body 2a clamped by the body
20 holding mechanism 91 from the previous step to the upper portion of the hermeticcontainer lower lid 2c in the welding device (STEP 3). At this time, the welding torch
20a and the welding torch 20b are located at the origins by the transverse cylinder 50.
[0037]
Then, the conveying robot 90 lowers the hermetic-container body 2a to fit the
25 hermetic-container body 2a to the upper portion of the hermetic-container lower lid 2c
(STEP 4). Since the lower fit portion 11 that is the fit portion of the lower portion of
the hermetic-container body 2a and the opening end portion of the hermetic-container
lower lid 2c is provided by the inclined surfaces 10 inclined at the same inclination
angle as described above, the inclined surfaces 10 are fitted to each other in a close30 contact manner. As described above, since the conveying robot 90 fits the hermetic-
13
container body 2a and the hermetic-container lower lid 2c to each other, fitting can be
performed while the perpendicularity of the hermetic-container body 2a relative to the
installation leg 2d is ensured as described above.
[0038]
5 Then, the welding device operates the moving mechanism 30 to adjust the
welding target positions of the two welding torches 20a and 20b (STEP 5).
Specifically, the welding device moves the welding torches to the welding positions by
the transverse cylinder 50 and adjusts the x direction, the y direction, and the target
angle c of each of the welding torches by the individual adjustment mechanism 60.
10 [0039]
Then, the welding device starts welding while the conveying robot 90 clamps
the hermetic-container body 2a. That is, for example, the welding device rotates the
turning main shaft 41 of the turning mechanism 40 to turn the welding torch 20a and
the welding torch 20b, for example, 210 degrees out of 360 degrees for one round in
15 the circumferential direction relative to the lower fit portion 11 and the upper fit portion
13 (STEP 6), and performs arc welding. When the welding torch 20a and the
welding torch 20b have rotated 210 degrees, the welding device releases the
clamping of the hermetic-container body 2a with the conveying robot 90, and causes
the conveying robot 90 to retract to the outside of a turning trajectory f of the welding
20 torches as illustrated in Fig. 11 (STEP 7). The retraction is performed so that the
conveying robot 90 does not interfere with the welding torch 20a and the welding
torch 20b when the welding torch 20a and the welding torch 20b weld the remaining
portions.
[0040]
25 The welding device then turns the welding torch 20a and the welding torch 20b
to 360 degrees and arc-welds the remaining portions (STEP 8). After the welding is
completed, the welding device causes the welding torch 20a and the welding torch
20b to traverse to the origin position by the transverse cylinder 50 (STEP 9).
[0041]
14
While the conveying robot 90 clamps the hermetic-container body 2a until the
welding torch turns 210 degrees in STEP 6, the conveying robot 90 clamps the
hermetic-container body 2a in a period from start of welding until the welding torch
turns at least halfway around or 180 degrees. Thus, it is possible to prevent
5 inclination of the hermetic-container body 2a due to distortion generated during
welding.
[0042]
As described above, the welding device according to Embodiment 1 includes
the two welding torches 20a and 20b, the turning mechanism 40 that turns the two
10 welding torches 20a and 20b in the circumferential direction of the hermetic-container
body 2a, and the body holding mechanism 91 that holds a portion of the hermeticcontainer body 2a of the hermetic container 2. In the welding device of Embodiment
1, the upper fit portion 13 and the lower fit portion 11 of the hermetic-container body
2a held by the body holding mechanism 91 each are arc-welded simultaneously while
15 the turning mechanism 40 turns the two welding torches 20a and 20b in the
circumferential direction of the hermetic-container body 2a. Thus, the lower fit
portion 11 and the upper fit portion 13 of the hermetic container 2 each can be
simultaneously welded. Since the lower fit portion 11 and the upper fit portion 13 of
the hermetic-container body 2a each can be simultaneously welded by turning the
20 welding torches, it is possible to prevent slipping between the fit portion of the
hermetic-container body 2a and the hermetic-container lower lid 2c, which is
generated when the hermetic container 2 is rotated and welded. As described
above, it is possible to suppress inclination of the hermetic-container body 2a during
welding, and it is possible to obtain weld portions of good quality. Consequently, the
25 performance of the hermetic compressor can be improved.
[0043]
The body holding mechanism 91 of Embodiment 1 holds the hermeticcontainer body 2a in the period from start of welding until welding for at least a half
round is completed. Thus, it is possible to prevent inclination of the hermetic30 container body 2a due to distortion generated during welding.
15
[0044]
The welding device according to Embodiment 1 includes the individual
adjustment mechanism 60 that is connected to the turning mechanism 40 and
individually adjusts each of the welding target positions of the two welding torches
5 20a and 20b. Thus, the welding target positions of the welding torch 20a and the
welding torch 20b can be individually adjusted.
[0045]
The conveying robot 90 that conveys the hermetic-container body 2a from the
previous step onto the mount table 70 is provided, and the conveying robot 90
10 includes the body holding mechanism 91. Thus, the configuration can be simplified
as compared to a case where the conveying robot 90 and the body holding
mechanism 91 are separately configured.
Reference Signs List
[0046]
15 1: hermetic compressor, 2: hermetic container, 2a: hermetic-container body, 2b:
hermetic-container upper lid, 2c: hermetic-container lower lid, 2d: installation leg, 3:
compression mechanism, 4: electric motor, 4a: rotor, 4b: stator, 5: crankshaft, 6:
attachment surface, 10: inclined surface, 11: lower fit portion, 12: protrusion, 13:
upper fit portion, 20a: welding torch, 20b: welding torch, 21: welding wire, 30: moving
20 mechanism, 40: turning mechanism, 41: turning main shaft, 42: turning auxiliary shaft,
43: driving unit, 43a: rotary motor, 50: transverse cylinder, 60: individual adjustment
mechanism, 61a: first mechanism, 61b: second mechanism, 62: in-plane position
adjustment mechanism, 62a: moving member, 63: angle adjustment mechanism, 63a:
rotary member, 70: mount table, 80: lower-lid holding mechanism, 81: base, 82:
25 column, 90: conveying robot, 91: body holding mechanism, 100: controller
16
We Claim :
[Claim 1]
A welding device configured to arc-weld an upper fit portion and a lower fit
portion of a hermetic container constituted by fitting a hermetic-container upper lid
5 and a hermetic-container lower lid to upper and lower portions of a cylindrical
hermetic-container body having upper and lower openings, the welding device
comprising:
two welding torches configured to perform arc welding;
a turning mechanism configured to turn the two welding torches in a
10 circumferential direction of the hermetic-container body; and
a body holding mechanism configured to hold a portion of the hermeticcontainer body of the hermetic container,
wherein the upper fit portion and the lower fit portion of the hermetic-container
body held by the body holding mechanism each are simultaneously arc-welded while
15 the turning mechanism turns the two welding torches in the circumferential direction
of the hermetic-container body.
[Claim 2]
The welding device of claim 1, wherein the body holding mechanism holds the
hermetic-container body in a period from start of welding until welding for at least a
20 half round is completed.
[Claim 3]
The welding device of claim 1 or 2, comprising an adjustment mechanism
coupled to the turning mechanism and configured to individually adjust a welding
target position of each of the two welding torches.
25
17
[Claim 4]
The welding device of any one of claims 1 to 3, comprising a conveying robot
configured to convey the hermetic-container body from a device in a previous step to
the welding device, the conveying robot including the body holding mechanism.