FIELD OF THE INVENTION
[0001] The present invention relates to a sealed type compressor to be used as a refrigerant
compressor for refrigerating and air conditioning or as an air compressor.
BACKGROUND OF THE INVENTION
[0002] In a conventional refrigerant compressor of this type, a compression mechanism 105
and a motor 106 to drive the compression mechanism 105 are fixed inside a sealed housing
104 which comprises an upper end plate 101, a body section 102, and a lower end plate
103 as shown in Fig. 20. The source of power to the motor 106 is supplied from an
external power supply (not shown) through a hermetic seal 110 having an electrically
conducting pin 109 insulated with a glass seal 108 on a cup-shaped metal member 107
which is hermetically sealed on the sealed housing 104.
[0003] A refrigerant is sucked through a suction pipe 111 leading to a refrigeration circuit
(not shown) into the compression mechanism 105, compressed, and discharged under a
high pressure into the sealed housing 104, and returned to the refrigeration circuit
(not shown) through a discharge pipe 112. Therefore, inside of the sealed housing
104 of this type of compressor is filled with a high-pressure refrigerant.
[0004] Although HCFC22 has heretofore been employed as a refrigerant for this type of compressors,
a decision has been reached to completely abolish it in the future because of a possibility
of depleting the ozone layer by its emission into the air. Among several alternative
HFC-based refrigerants to replace HCFC22, R407C, which is a mixture of HFC125, HFC32,
and HFC134a, and R410A, which is a mixture of HFC125 and HFC32, are considered to
be promising candidates. While the discharge pressure of R407C is approximately equal
to that of R22, the discharge pressure of R410A is approximately 1.7 times that of
R22.
[0005] When using an alternative refrigerant having such a high discharge pressure in a
sealed type compressor of high-pressure type in which the discharge pressure is applied
to the sealed housing itself, the pressure-resistance strength of the sealed housing
needs to be increased. However, in the above-mentioned prior art structure, as the
internal pressure of the sealed housing 104 increases, the upper and lower end plates
101 and 103 swell outward gradually assuming a sphere-like shape. As the hermetic
terminal 110 is fixed by welding to a flat section of the upper end plate 101, the
deformation causes a stress on the cup-shaped metal member 107 of the hermetic terminal
110, thus deforming it and breaking the glass seal 108, and leaking the high-temperature
high-pressure refrigerant to outside. In the prior art construction, as this is the
section of which the pressure-resistance strength is the weakest, it is necessary
to increase pressure-resistance strength of this section in order to increase the
pressure-resistance strength of the entire sealed housing.
[0006] Also, the joints between the sealed housing 104 and the connecting pipes for the
refrigerant, namely, the suction pipe 111 and the discharge pipe 112, are parts with
the weakest pressure-resistance strength after the hermetic terminal 110 because a
tensile stress is exerted due to the high pressure inside the sealed housing 104.
SUMMARY OF THE INVENTION
[0007] The present invention has been contrived in order to address the above-described
problems of the prior art, and is aimed in particular to prevent breakage of the glass
seal of the hermetic terminal, and additionally to improve the pressure-resistance
strength of the joints between the sealed housing and connecting pipes for a refrigerant,
and to provide a sealed housing with a pressure-resistance strength high enough to
withstand high-pressure alternative refrigerants.
[0008] For this purpose, in the present invention, a member, such as a ring-shaped metal
member, to enhance rigidity of the sealed housing of a sealed type compressor is welded
to the welded joints of the hermetic terminal and the connecting pipes for the refrigerant
which are to be hermetically welded to the sealed housing in such a way that the member
encircles the welded joints. As a result, inside of the sealed housing becomes high
in pressure, and, in the case of the hermetic terminal, even when the sealed housing
to which the hermetic terminal and connecting pipes for refrigerant are welded is
deformed, the rigidity member such as the ring-shaped metal member joined to the outer
periphery of the welded joint of the hermetic terminal suppresses the deformation
of the hermetic terminal and prevents breakage of the glass seal of the hermetic terminal,
whereas, in the case of the connecting pipes, the ring-shaped metal member joined
to the outer periphery of their welded joints reduces the tensile stress produced
in the welded joints, thus improving the joining strength of the connecting pipes
and improving the pressure-resistance strength of the sealed housing.
[0009] In other words, in this invention, a motor and a compression mechanism to be driven
by the motor are disposed inside a sealed housing, a hermetic terminal hermetically
welded to the sealed housing (including end plates and a flat section) to supply electric
power to the motor from outside the sealed housing comprises a cup-shaped metal member,
an electrically conducting pin, and a glass seal to insulate the cup-shaped metal
member and the electrically conducting pin, and a member to increase rigidity (deformation
rigidity) against deformation of the sealed housing is welded to the sealed housing
encircling the welded joint between the sealed housing and the hermetic terminal.
[0010] Also, in this invention, the member to increase deformation rigidity of the sealed
housing is preferably a ring-shaped metal member having a thickness greater than 1/3
of the thickness of the sealed housing, and the weld where the ring-shaped metal member
is welded to the sealed housing is preferably an arc in shape. By so doing, the deformation
rigidity of that section of the sealed housing where the ring-shaped metal member
is welded effectively suppresses deformation of the hermetic terminal.
[0011] Also, in this invention, the ring-shaped metal member is welded to the inside of
the sealed housing. By welding to the inside, obstruction to a protecting frame member
of the hermetic terminal to be formed on the outside and to wiring around leads of
the power supply can be avoided.
[0012] Also, in this invention, by welding the ring-shaped metal member to the outside of
the sealed housing preferably integrally with a protecting frame member of the hermetic
terminal, welding of the hermetic terminal to the sealed housing is not obstructed,
and integral welding with the protecting frame member is possible, thus making assembling
work easy.
[0013] Also, in this invention, either by providing a linear protrusion on the welded joint
with the sealed housing when welding the ring-shaped metal member to the sealed housing,
or by resistance welding as is when the width of the ring is small, the entire ring
surface is fixed by welding to the end plates and the like of the sealed housing,
thereby the deformation rigidity of the end plates and the like of the sealed housing
effectively suppresses deformation of the hermetic terminal. When carrying out resistance
welding, the width of the ring-shaped metal member will need to be narrowed in order
to increase the current density.
[0014] Also, in this invention, as a burring-processed hole is provided on the sealed housing
and the hermetic terminal is hermetically welded to the hole, deformation of the peripheral
edge of the hermetic terminal is made difficult to take place because of burring,
thus making it possible to prevent breakage of the glass seal and improve the pressure-resistance
strength. When burring is provided on the inside the sealed housing, hermetic welding
of the hermetic terminal is made easy. When burring is provided on the inside of the
sealed housing, hermetic welding of the hermetic terminal becomes easy. When burring
is provided on the outside of the sealed housing, deforming force exerted to the glass
seal becomes smaller than when burring is provided on the inside.
[0015] Also, in this invention, the hermetic terminal is once hermetically welded onto a
steel plate followed by hermetically welding the steel plate on the end plate etc.
of the afore-mentioned sealed housing with some overlap between them, thus making
inside of the sealed housing high in pressure. As the rigidity of the overlapping
section is large, even when the end plates etc. of the sealed housing onto which the
hermetic terminal is welded are deformed, deformation of the hermetic terminal is
suppressed, breakage of the glass seal of the hermetic terminal is prevented, and
the pressure-resistance strength is improved. When the thickness of the steel plate
on to which the hermetic terminal is hermetically welded is greater than the thickness
of the sealed housing (end plates etc.), and when the length of the overlap of the
steel plate and the sealed housing is greater than the thickness of the sealed housing,
the effect of suppressing deformation of the hermetic terminal and preventing breakage
of the glass seal becomes more prominent.
[0016] Also, this invention is especially effective in a sealed type compressor in which
the afore-mentioned sealed housing comprises a body section and an end plate to close
an opening of the body section, and a hermetic terminal is hermetically welded to
the end plate.
[0017] Also, in this invention, an attempt is made to improve pressure-resistance strength
of the connecting sections of the connecting pipes (discharge pipe and suction pipe)
connecting inside and outside of the sealed housing and through which a refrigerant
goes in and out. By welding the ring-shaped metal member to the outer periphery of
the welded joint of the connecting pipes, the tensile stress produced in the welded
joint by the deformation due to internal pressure of the sealed housing is reduced
and the pressure-resistance strength of the connecting sections of the connecting
pipes is improved. Also, it is preferable to weld the connecting pipes to a burring-processed
hole of the sealed housing for further improvement of the pressure-resistance strength.
Furthermore, as the connecting pipes are generally welded by copper brazing, assembling
becomes easy if the nearby ring-shaped metal member is brazed at the same time.
[0018] Also, in this invention, holes with a diameter equal to or smaller than the inner
diameter of the connecting pipes connecting inside and outside of the afore-mentioned
sealed housing and through which a refrigerant goes out and comes in are made and
end faces of the connecting pipes are fixed by welding to the outside surface of the
sealed housing corresponding to the holes. As a result, when a high pressure is applied
to the inside of the sealed housing, a large tensile stress is not applied to the
welded joint as its position is different from the prior art. Consequently, pressure-resistance
strength of the sealed housing can be improved. Also, by expanding the end faces of
the connecting pipes on the side to be fixed by welding to the sealed housing and
by increasing the diameter of the holes of the sealed housing, it is also possible
to reduce resistance against flow of the refrigerant.
[0019] Also, in this invention, by fixing the connecting pipes to the sealed housing by
diffusion welding, the temperature rise during welding is made smaller than that of
brazing and other methods of welding, and thus the strength of the pipes can be maintained.
[0020] Also, in this invention, recessed sections having a diameter equal to or slightly
larger than the outside diameter of the connecting pipes are formed on the periphery
of the holes of the sealed housing, and end sections of the connecting pipes are inserted
into the recessed sections and fixed by welding. Generally, by fixing both of end
faces and periphery of the end sections of the connecting pipes to the sealed housing
by brazing, in the event a high pressure is applied to the inside of the sealed housing,
breakage is hard to take place because of existence of welded joints at two locations
facing different directions thus contributing to improvement of the pressure-resistance
strength of the sealed housing. Furthermore, enough strength is secured in the event
a large force (e.g., tensile force) is applied to the afore-mentioned connecting pipes.
[0021] Also, in this invention, when the sealed housing comprises a body section and end
plates to close openings of the body section as set forth above, and the afore-mentioned
hermetic terminal and one of the afore-mentioned connecting pipes are welded to the
end plates, the above-described structure of the welded joint will prove all the more
effective in the event an internal pressure of the sealed housing is exerted because
the deformation of the end plate section is large.
[0022] Also, this invention is more effective when a high-pressure refrigerant HFC32 or
a mixed refrigerant containing HFC32 is used as the refrigerant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023]
Fig. 1 is a vertical cross sectional view of a sealed type compressor in a first exemplary
embodiment of the present invention, Fig. 2 is a vertical cross sectional view of
a hermetic terminal section of the compressor, Fig. 3 is a cross sectional view of
a ring-shaped metal member of the compressor, Fig. 4 is a vertical cross sectional
view of other configuration 1 of the hermetic terminal section, Fig. 5 is a vertical
cross sectional view of other configuration 2 of the hermetic terminal section, Fig.
6 is a vertical cross sectional view of other configuration 3 of the hermetic terminal
section, and Fig. 7 is a vertical cross sectional view of other configuration 4 of
the hermetic terminal section.
Fig. 8 is a vertical cross sectional view of a hermetic terminal section in a second
exemplary embodiment of the present invention, Fig. 9 is a vertical cross sectional
view of other configuration 1 of the hermetic terminal section, and Fig. 10 is a vertical
cross sectional view of other configuration 2 of the hermetic terminal section.
Fig. 11 is a vertical cross sectional view of a hermetic terminal section in a third
exemplary embodiment of the present embodiment.
Fig. 12 is a vertical cross sectional view of a connecting pipe section in a fourth
exemplary embodiment of the present invention, Fig. 13 is a vertical cross sectional
view of other configuration 1 of the connecting pipe section, Fig. 14 is a vertical
cross sectional view of other configuration 2 of the connecting pipe section, Fig.
15 is a vertical cross sectional view of other configuration 3 of the connecting pipe
section, Fig. 16 is a vertical cross sectional view of other configuration 4 of the
connecting pipe section, and Fig. 17 is a vertical cross sectional view of other configuration
5 of the connecting pipe section.
Fig. 18 is a vertical cross sectional view of a connecting pipe section in a fifth
exemplary embodiment of the present invention.
Fig. 19 is a vertical cross sectional view of a connecting pipe section in a sixth
exemplary embodiment of the present invention.
Fig. 20 is a cross sectional view of a prior art sealed type compressor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Exemplary embodiments of the present invention are described with respect to the
figures.
First Exemplary Embodiment:
[0025] Fig. 1 is a vertical cross sectional view of a sealed type compressor in a first
exemplary embodiment of the present invention. As shown in the figure, the sealed
type compressor has a structure in which a compression mechanism 5 and a motor 6 to
drive the compression mechanism 5 are disposed inside a sealed housing 4 which comprises
an upper end plate 1, a cylindrical body section 2, and a lower end plate 3. Although
details of the compression mechanism 5 are not shown, it can be of a rotary type or
a scroll type. Electric power for the motor 6 is supplied from an external power supply
(not shown) through a hermetic terminal 8 which is hermetically welded to a hole 7
provided on the upper end plate 1 of the sealed housing 4.
[0026] A refrigerant is sucked through a suction pipe 9 (connecting pipe) that leads to
a refrigerating circuit (not shown), compressed by the compression mechanism 5, discharged
into the sealed housing 4 with a high pressure, and returned to the refrigerating
circuit (not shown) through a discharge pipe 10 (connecting pipe). Accordingly, in
this exemplary embodiment, the inside of the sealed housing 4 is filled with a high-pressure
refrigerant, a structure so-called high-pressure type compressor.
[0027] Fig. 2 is an enlarged view of the hermetic terminal 8 of the sealed type compressor
shown in Fig. 1. The hermetic terminal 8 has on the top surface of a cup-shaped metal
member 11 an electrically conducting pin 13 insulated by a glass seal 12. The bottom
part of the cup-shaped metal member 11 has a skirt section 14 expanded like a skirt,
with which the cup-shaped metal member 11 is hermetically welded to the hole 7 provided
on a flat section of the upper end plate 1. A ring-shaped metal member 15 being a
member to enhance rigidity (rigidity against deformation of the flat section) of the
sealed housing 4 is welded to the outer periphery of the skirt section 14, which is
inside the sealed housing 4, of the hermetic terminal 8.
[0028] The material of the ring-shaped metal member 15 is generally-available steel and
its thickness is set to a value greater than 1/3 of the thickness of the upper end
plate 1. To be more specific, in this exemplary embodiment, the thickness of the end
plate 1 of the sealed housing 4 made of steel is chosen to be between 3 mm nd 4 mm
while the thickness of the ring-shaped metal member 15 is chosen to be between 1.5
mm and 5 mm. The width of the ring of the ring-shaped metal member 15 is chosen to
be between 2 mm and 4 mm. The inner diameter of the ring-shaped metal member 15 is
set to be greater than the outer diameter of the skirt section 14 of the hermetic
terminal 8.
[0029] Assembling by welding of the ring-shaped metal member 15 and the hermetic terminal
8 onto the upper end plate 1 is next described. At the location on the upper end plate
1 where the hermetic terminal 8 is to be disposed, a hole 7 slightly larger than the
outer diameter of the cup-shaped metal member 11 is made on a surface (flat section)
16 with a relatively high degree of flatness. The ring-shaped metal member 15 is fixed
by resistance welding to the outer periphery of the hole 7. Resistance welding is
generally accomplished by concentrating an electric current by providing a protrusion
on the part to be welded. However, in this exemplary embodiment, as resistance welding
based on a protrusion produces dotted welds, it is not adopted because the ring-shaped
metal member 15 will not suppress deformation of the upper end plate 1 of the sealed
housing 4. Consequently, in this invention, a surface 1a of the ring-shaped metal
member 15 which comes in contact with the upper end plate 1 is made flat with a relatively
high degree of flatness, and is made in close contact with the flat section 16 of
the upper end plate 1, and then resistance welding is carried out by allowing an electric
current to flow. In this case, though rigidity increases as the width of the ring
increases, the current density is not increased and thus the entire surface is not
uniformly welded. Accordingly, the above-described range of width of 2 mm to 4 mm
is adequate. By welding in this way, an arc-shaped welded joint is obtained, and the
ring-shaped metal member 15 acts to suppress the deformation of the upper end plate
1. In the case of a ring-shaped metal member 15 with a large width or when welding
without allowing too large an electric current to flow, a linear protrusion 18 is
provided on the tip 17 of the ring-shaped metal member 15 as shown in Fig. 3. Although
it is general practice to provide the linear protrusion 18 over the entire circumference,
it may be good to divide into 3 or 4 arc sections.
[0030] Evaluation of pressure resistance of the sealed housing 4 of the sealed type compressor
of the present exemplary embodiment is next described.
[0031] Generally, the pressure resistance requirement on a sealed, housing of a refrigerant
compressor is that it will not break when a static hydraulic pressure equal to 3 to
5 times the designed pressure value (maximum operating pressure) is applied, though
a slight difference exists depending on standards and laws of different countries.
When a static hydraulic pressure equal to 3 to 5 times the designed pressure value
is gradually applied to inside the sealed housing 4 of this exemplary embodiment,
the sealed housing 4 gradually swells, especially the upper end plate 1 swells in
the shape of a sphere. In the absence of the ring-shaped metal member 15, the skirt
section 14 of the hermetic terminal 8 fixed by welding to the flat section 16 will
become part of a spherical surface and is forced inward with a strong force. Because
of this force and the internal static hydraulic pressure, the glass seal 12 also tends
to expand outwardly in the shape of a sphere thus exerting a large force on the sealing
glass causing cracks in the glass and leakage of water. However, in this exemplary
embodiment, although the flat section 16 (upper end plate 1) where the hermetic terminal
8 of the sealed housing 4 is welded tends to deform in the shape of a sphere, the
ring-shaped metal member 15 fixed by welding to the flat section 16 of the sealed
housing 4 suppresses the deformation, and also suppresses the skirt section 14 of
the hermetic terminal 8 from being forced inwardly with a strong force, thereby preventing
breakage of the glass seal 12. Consequently, a sealed housing 4 having a pressure-resistance
strength high enough for a high-pressure refrigerant such as R410A containing HFC32
can be realized.
[0032] Regarding the method of welding, although resistance welding was described in the
foregoing, brazing may also be used with which the welded joint between the ring-shaped
metal member 15 and the flat section 16 of the sealed housing 4 becomes an arc in
shape. Also, even when the ring-shaped metal member 15 is not a perfect circular ring
having some local cuts, or when a plurality of bow-shaped metal members are disposed
encircling the weld of the hermetic terminal 8, they act to enhance the deformation
rigidity of the sealed housing 4 exhibiting equivalent effect. Also, in preventing
the deformation of the sealed housing 4 from exerting a large force to the glass seal
12 of the hermetic terminal 8, it is preferable to make the length of the weld to
1/4 of the circumference or greater, and the members to enhance the rigidity should
preferably cover 2/3 or more of the total circumference of the weld of the hermetic
terminal 8.
[0033] Although the ring-shaped metal member 15 is welded to the inside of the sealed housing
4 (upper end plate 1) in the hermetic terminal of the above-described exemplary embodiment,
it may be welded to the outside of the sealed housing 4 as shown in Fig. 4. In this
case, welding of the ring-shaped metal member 15 and the hermetic terminal 8 is relatively
easy. Furthermore, as a protecting frame member 19 for the hermetic terminal 8 is
generally disposed on the outside of the sealed housing 4, assembling work becomes
easy by welding it integrally with the hermetic terminal 8 as shown in Fig. 5. Also,
the shape of the ring-shaped metal member 15 may be that of a burring-processed ring-shaped
metal member 15a such as shown in Fig. 6 and Fig. 7.
[0034] Also, though description of the material of the ring-shaped metal members 15, 15a
was made with reference to steel, more pronounced rigidity effect may be obtained
by the use of high-tension steel.
Second Exemplary Embodiment:
[0035] Figs. 8 to 10 illustrate a hermetic terminal section in a second exemplary embodiment
of the present invention.
[0036] As shown in Fig. 8, a hole 7 provided on an upper end plate 1 has a burring 20 formed
toward the inside of a sealed housing 4. An end face 20a of the burring section 20
is processed into a flat surface, where a skirt section 14 of a hermetic terminal
8 is fixed by welding.
[0037] In this exemplary embodiment, as the internal pressure of the sealed housing 4 increases,
the sealed housing 4 gradually swells, and the upper end plate 1 swells in the shape
of a sphere. However, as the rigidity of the burring 20 is large, it acts to suppress
the deformation of its inner part, and prevents breakage of a glass seal 12 of the
hermetic terminal 8. Furthermore, in this exemplary embodiment, as welding of the
hermetic terminal 8 is possible even when the outer periphery of the hole 7 is made
in the shape of a spherical surface, the deformation of the upper end plate 1 is reduced
and the pressure-resistance strength of the upper end plate 1 can be improved. Also,
the cost will be less compared with the afore-mentioned welding of the ring-shaped
metal members 15 and 15a.
[0038] Also, the hermetic terminal section shown in Fig. 9 has the above-mentioned burring
20 formed toward the outside of the sealed housing 4 (upper end plate 1). Similarly
to the burring 20 formed toward the inside, rigidity of the peripheral edge of the
hermetic terminal 8 is increased by the burring 20 making deformation difficult to
take place, thus preventing breakage of the glass seal 12 and increasing the pressure-resistance
strength. Deforming force exerted on the glass seal 12 is smaller when the burring
20 is formed on the outside than when it is formed on the inside. However, unless
the flatness of the base part of the burring 20 is precisely obtained, welding with
the hermetic terminal 8 becomes difficult.
[0039] Also, the hermetic terminal section shown in Fig. 10 is obtained by welding the ring-shaped
metal member 15a to the outer periphery of the burring 20 shown in Fig. 9, the welding
of which providing further enhancement of the rigidity.
Third Exemplary Embodiment:
[0040] Fig. 11 shows a hermetic terminal section in a third exemplary embodiment of the
present invention.
[0041] A hermetic terminal 8 is hermetically welded to a doughnut-shaped flat plate 21 made
of steel. The thickness of the flat plate 21 is set to be greater than an upper end
plate 1 of a sealed housing 4. The flat plate 21 is hermetically welded to the upper
end plate 1 with an overlap 22. The length of the overlap 22 is greater than the thickness
of the upper end plate 1. When the overlap 22 is large, by welding both of the inner
end 22a and the outer end 22b of the overlap of the flat plate 21 with the upper end
plate 1, the rigidity can be further enhanced.
[0042] In this exemplary embodiment, as the pressure inside the sealed housing 4 increases,
the sealed housing 4 gradually swells, especially the upper end plate 1 swells in
the shape of a sphere. However, as the overlap 22 between the doughnut-shaped flat
plate 21 made of steel and the upper end plate 1 is fixed by welding, the thickness
is increased and rigidity is increased, thus suppressing the deformation of the inner
part and preventing breakage of a glass seal 12 of the hermetic terminal 8. As a result,
it is possible to obtain a sealed housing 4 with a pressure-resistance strength high
enough for a high-pressure refrigerant containing HFC32 such as R410a.
[0043] Meanwhile, unless the thickness of the flat plate 21 is made greater than that of
the upper end plate 1, the effect of preventing breakage of the glass seal 12 of the
hermetic terminal 8 cannot be fully exhibited because the flat plate 21 itself deforms.
Also, when the overlap 22 is small, the effect of preventing breakage of the glass
seal 12 of the hermetic terminal 8 cannot be fully exhibited as bending takes place
there. The length of the overlap 22 is required to be greater than the thickness of
the upper end plate 1. It produces the same effect whichever of the upper end plate
1 and the flat plate 21 is welded inside.
Fourth Exemplary Embodiment:
[0044] Figs. 12 through 17 illustrate a connecting pipe section through which a refrigerant
goes in and out in a fourth exemplary embodiment of the present invention. As shown
in Fig. 12, a discharge pipe 10, being one of the connecting pipes through which the
refrigerant goes in and out from a sealed housing 4, is fixed by welding to an upper
end plate 1, followed by welding a ring-shaped metal member 23 on the outer periphery
of the weld. When a pressure is applied to the inside of the sealed housing 4, the
upper end plate 1 deforms in the shape of a sphere. In the absence of the ring-shaped
metal member 23, a tensile stress concentrates at a brazed section 24 joining the
discharge pipe 10 and the upper end plate 1, and fracture is caused. However, in this
structure, even when the upper end plate 1 deforms in the shape of a sphere, the deformation
in the vicinity of the weld of the discharge pipe 10 is suppressed and the tensile
stress is eased, thus preventing leakage of the high-pressure refrigerant to outside
due to fracture of the brazed section 24, and improving the pressure-resistance strength.
[0045] Although the ring-shaped metal member 23 is welded to the inside of the sealed housing
4 in the above-described exemplary embodiment, it may be welded to the outside of
the sealed housing 4 as shown in Fig. 13. Also, the shape of the ring-shaped metal
member 23 may be that of the ring-shaped metal member 23a having a burring as shown
in Figs. 14 and 15. Furthermore, by forming a burring 25 on the outer periphery of
the weld of the upper end plate 1 and the discharge pipe 10, and welding the ring-shaped
metal member 23a on the outer periphery of the burring 25, the rigidity may be further
enhanced. Also, as connecting pipes are generally welded by copper brazing, assembling
becomes easier by brazing the nearby ring-shaped metal members 23 and 23a at the same
time.
[0046] As set forth above, in the present invention, when the sealed housing 4 comprises
the body section 2, the upper end plate 1 and the lower end plate 3, and the hermetic
terminal 8 and the discharge pipe 10 are welded to the upper end plate 1, the invention
is still more effective as the deformation of the upper end plate 1 is large. Also,
the effect is more pronounced when used for a high-pressure refrigerant HFC32 or a
high-pressure mixed refrigerant such as R410A containing HFC32.
Fifth Exemplary Embodiment:
[0047] Fig. 18 shows a connecting pipe section through which a refrigerant goes in and out
in a fifth exemplary embodiment of the present invention. A small hole 26 having a
diameter equal to or smaller than the inner diameter of a discharge pipe 10 being
a connecting pipe is made on a flat section 16 of a sealed housing 4 (upper end plate
1), and the end face 10a of the discharge pipe is fixed by welding to the flat section
16 corresponding to the hole 26. As a method of welding, silver brazing may be adopted.
However, a greater pipe strength may be obtained by employing diffusion welding in
which an electric current is allowed to flow while a discharge pipe 10 made of copper,
for instance, is being pressed to the flat section 16 thus making copper of the discharge
pipe 10 diffuse into the sealed housing 4 because the temperature rise is smaller
when compared with welding by brazing and the like.
[0048] When a large pressure is applied to the inside of the sealed housing 4, the upper
end plate 1 deforms in the shape of a sphere. If the position of the welded joint
of the discharge pipe 10 is inside of the hole as in the prior art, a tensile stress
in the direction of opening the welded joint is exerted by the spherical deformation
of the upper end plate 1. However, since the position of the welded joint of the end
face 10a of the discharge pipe is on the surface of the upper end plate 1 differently
from the prior art, no crack and the like will be caused on the welded joint as no
tensile stress is exerted, thus improving the pressure-resistance strength of the
sealed housing 4. Also, the resistance to refrigerant flow may be reduced by expanding
that end face 10a of the discharge pipe 10 which is on the side to be fixed by welding
to the upper end plate 1 and by expanding the diameter of the hole 26 on the upper
end plate 1.
Sixth Exemplary Embodiment:
[0049] Fig. 19 shows a connecting pipe section through which a refrigerant goes in and out
in a sixth exemplary embodiment of the present invention. A small hole 26 having a
diameter equal to or smaller than the inner diameter of a discharge pipe 10 is made
on a flat section 16 of a sealed housing 4 (upper end plate 1). A recessed section
28 having a diameter equal to or slightly larger than the outer diameter of the discharge
pipe 10 is made on the periphery of the hole 26, into which the discharge pipe end
section 10b is inserted, and both the outer periphery of the discharge pipe end section
10b and the discharge pipe end face 10a are fixed by brazing and the like.
[0050] In the above structure, when a large pressure is applied to the inside of the sealed
housing 4, the upper end plate 1 is deformed in the shape of a sphere. If the position
of the welded joint of the discharge pipe 10 is inside the hole as in the prior art,
a tensile stress in the direction of opening the welded joint is exerted by the spherical
deformation of the upper end plate 1. In the above structure, however, as the position
of the welded joint is at both the outer periphery of the discharge pipe end section
10b and the discharge pipe end face 10a, even though a tensile stress is exerted to
the outer periphery of the discharge pipe end section 10b, a crack will not extend
to the weld of the discharge pipe end face 10a thus maintaining hermeticity. Also,
when a force is exerted to the discharge pipe 10, though a bending stress is exerted
to the weld, the outer periphery of the discharge pipe end section 10b inserted in
the recessed section 28 supports it, thus relieving the discharge pipe end face 10a
from the tensile stress and providing enough strength to the welded joint.
[0051] In the fifth and sixth exemplary embodiments, when a structure in which the sealed
housing comprises a body section and upper and lower end plates is used to welding
of a hermetic terminal and one of the connecting pipes to one of the end plates, one
of the end plates will have two or more holes causing larger deformation. Therefore,
employment of the above-described method of welding will be further effective. Also,
when applied to refrigerants in general such as R22 and the like, cost reduction may
be possible by reducing the thickness of the sealed housing or the grade of its material.
When applied to high-pressure refrigerants such as HFC32 or R410A containing HFC32,
the pressure resistance of the sealed housing may be more effectively improved.
[0052] As has been described in the foregoing exemplary embodiments, in the present invention,
a member to enhance rigidity of the sealed housing is welded to the sealed housing
encircling the weld of the hermetic terminal. Consequently, even when the inside of
the sealed housing becomes high in pressure and the sealed housing to which the hermetic
terminal is welded is deformed, the member to enhance the rigidity of the outer periphery
of the weld of the hermetic terminal suppresses the deformation of the hermetic terminal
and prevents breakage of the glass seal of the hermetic terminal, thus realizing a
sealed type compressor having a high pressure resistance.
[0053] Also, by resistance welding the ring-shaped metal member to the sealed housing, the
entire area of the ring-shaped metal member can be fixed by welding to the sealed
housing, thus deformation of the end plates can effectively suppress deformation of
the hermetic terminal and a sealed type compressor with a high pressure-resistance
strength can be realized.
[0054] Also, in this invention, by providing a burring-processed hole on the sealed housing
and hermetically welding the hermetic terminal to the hole, deformation of the periphery
of the hermetic terminal is made difficult to take place because of the burring, thus
preventing breakage of the glass seal and improving the pressure-resistance strength.
[0055] Also, in this invention, the hermetic terminal is once hermetically welded to a plate
material followed by hermetically welding the plate material to the sealed housing
with an overlap. As a result, in the event the inside of the sealed housing becomes
high in pressure and the end plate to which the hermetic terminal is welded deforms,
it is possible to suppress the deformation of the hermetic terminal as the rigidity
of the overlap is large and to prevent breakage of the glass seal of the hermetic
terminal thus realizing a sealed type compressor having a large pressure-resistance
strength.
[0056] The invention is especially effective in a structure in which a sealed housing comprises
a body section and end plates closing an opening of the body section, and a hermetic
terminal is hermetically welded to an end plate.
[0057] Also, in this invention, by welding a ring-shaped metal member on the outer periphery
of the weld of the connecting pipes (discharge pipe and suction pipe), the tensile
stress produced in the weld by the deformation of the sealed housing due to internal
pressure of the connecting pipes is reduced, and the pressure-resistance strength
of the joints of the connecting pipes is improved. Furthermore, by brazing both the
connecting pipes and the ring-shaped metal member, assembling becomes easy.
[0058] Also, in this invention, a hole having a diameter equal to or smaller than the inner
diameter of a connecting pipe is made on a flat section of the sealed housing and
end face of the connecting pipe is fixed by welding to the outside surface of the
sealed housing. As a result, in the event a high pressure is exerted to the inside
of the sealed housing, no large tensile stress is exerted to the weld thus the pressure-resistance
strength of the sealed housing is improved.
[0059] The invention also provides a recessed section in the periphery of a hole on the
sealed housing into which an end portion of a connecting pipe is inserted and fixed
by welding. By fixing by welding both the end face of the connecting pipe and the
outer periphery of the end portion, in the event a large force is exerted to the pipe,
breakage is hard to take place as welded joints exist at two locations facing different
directions, thus improving pressure-resistance strength of the sealed housing and
providing a sealed type compressor with a strength high enough to withstand a large
force that may be exerted to the pipes.
[0060] Also, when the sealed housing comprises a body section and end plates and a hermetic
terminal and connecting pipes are welded to the end plates, the invention is further
effective as the deformation of the end plates is large.
[0061] When practiced with a high-pressure refrigerant HFC32 or a refrigerant containing
HFC32, the effect of the invention is more pronounced.