TECHNICAL FIELD
[0001] The present invention relates to a sealed compressor and a refrigeration device such
as a household-use electric freezer refrigerator or a show case using the sealed compressor.
BACKGROUND ART
[0002] Recently, along with diversification of food materials, a demand for the increase
of capacity of an indoor volume of the household-use electric freezer refrigerator
is increasing. As one of methods for increasing the indoor volume while maintaining
a size of an external appearance of the household-use electric freezer refrigerator,
the reduction in size of a machine compartment which houses a sealed compressor has
been in progress. In the sealed compressor used in the household-use electric freezer
refrigerator, other refrigeration cycle devices and the like, the miniaturization
and the reduction in height of the sealed compressor have been strongly required.
[0003] Conventionally, with respect to this type of sealed compressor, to achieve the miniaturization
and the reduction in height of the sealed compressor, there has been known a sealed
compressor which uses an outer-rotor-type motor suitable for the miniaturization and
the reduction in thickness of the sealed compressor in place of an inner-rotor-type
motor (see Patent Literature 1, for example). A rotor rotates inside a stator as an
electrically-operated element in the inner-rotor-type motor, while a rotor rotates
outside a stator in the outer-rotor-type motor.
[0004] Fig. 7 is a side view showing a bearing mechanism and an electrically-operated element
of a conventional sealed compressor (see Patent Literature 1).
[0005] As shown in Fig. 7, the conventional sealed compressor includes: shaft 8 having main
shaft 4 and eccentric shaft 6; and bearing 10 which pivotally supports main shaft
4. Sliding portions 12, 14 are formed on an outer peripheral surface of main shaft
4 and an inner peripheral surface of bearing 10, respectively.
[0006] Electrically-operated element 18 is an outer-rotor-type motor which is formed of:
stator 20; and rotor 22 which surrounds stator 20 and is disposed coaxially with stator
20.
[0007] Stator 20 is fixed to outer peripheral surface 23 of bearing 10 by welding, shrinkage
fitting, press-fitting or the like. Sliding portion 14 is mounted on an inner periphery
of bearing 10 to which stator 20 is fixed.
[0008] Further, in rotor 22, permanent magnet 28 is disposed on outer peripheral end portion
26 of disc-like frame 24. Rotor 22 is fixed to an outer periphery of a lower end of
shaft 8 by circular cylindrical rotor shaft hole 30 formed on a center of frame 24
by shrinkage fitting or the like.
[0009] However, in the conventional configuration described in Patent Literature 1, stator
20 is fixed to outer peripheral portion 23 of bearing 10 by welding, shrinkage fitting,
press-fitting or the like. Accordingly, in the conventional configuration, the inner
peripheral surface of bearing 10 to which stator 20 is fixed is deformed so that the
conventional configuration has a drawback that a solid contact occurs between the
inner peripheral surface of bearing 10 and sliding portion 12 of main shaft 4 and
hence, wear is liable to occur between the inner peripheral surface of bearing 10
and sliding portion 12 of main shaft 4.
Citation List
Patent Literature
[0010] PTL 1: Unexamined German Patent Publication
102010051266 Specification
SUMMARY OF THE INVENTION
[0011] The present invention has been made to overcome the above-mentioned drawbacks, and
it is an object of the present invention to provide a sealed compressor having high
durability in such a manner that when a stator is fixed to an outer peripheral surface
of a bearing, the deformation of an inner peripheral surface of the fixed bearing
is reduced so that a solid contact which occurs between the bearing and a main shaft
is avoided whereby the occurrence of wear can be prevented.
[0012] In a sealed compressor of the present invention, an electrically-operated element
and a compressive element driven by the electrically-operated element are housed in
the inside of a sealed container. The compressive element includes: a shaft formed
of a main shaft and an eccentric shaft; a cylinder block having: a bearing which pivotally
supports the main shaft of the shaft; and a cylinder; a piston which is movable in
the cylinder in a reciprocating manner; and a connecting portion which connects the
eccentric shaft and the piston to each other. The electrically-operated element is
an outer-rotor-type motor which includes: a stator; and a rotor which surrounds an
outer periphery of the stator and is disposed coaxially with the stator. The stator
is fixed to an outer peripheral surface of the bearing by an adhesive agent.
[0013] With such a configuration, it is possible to reduce the deformation of an inner peripheral
surface of the bearing which occurs when the stator is fixed to the outer peripheral
surface of the bearing. Accordingly, a solid contact which occurs between the bearing
and the main shaft is avoided so that the occurrence of wear can be prevented.
[0014] In the sealed compressor of the present invention, the stator is fixed to the outer
peripheral surface of the bearing by an adhesive agent and hence, compared to the
case where the stator is fixed to the outer peripheral surface of the bearing by welding,
shrinkage fitting, press-fitting or the like, the deformation of the inner peripheral
surface of the bearing can be reduced. Therefore, a solid contact which occurs between
the bearing and the main shaft is avoided and hence, the occurrence of wear can be
prevented. Accordingly, the durability of the sealed compressor can be enhanced.
BRIEF DESCRIPTION OF DRAWINGS
[0015]
FIG. 1 is a cross-sectional view of a sealed compressor according to a first exemplary
embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view showing a fixing portion between a stator
and a bearing of the sealed compressor according to the first exemplary embodiment
of the present invention.
FIG. 3 is a bottom view as viewed from below of the stator and the bearing of the
sealed compressor according to the first exemplary embodiment of the present invention.
FIG. 4 is another enlarged cross-sectional view showing the fixing portion between
the stator and the bearing of the sealed compressor according to the first exemplary
embodiment of the present invention.
FIG. 5 is still another enlarged cross-sectional view showing the fixing portion between
the stator and the bearing of the sealed compressor according to the first exemplary
embodiment of the present invention.
FIG. 6 is a schematic view showing a refrigeration device according to a second exemplary
embodiment of the present invention.
FIG. 7 is a side view showing a bearing mechanism and an electrically-operated element
of a conventional sealed compressor.
DESCRIPTION OF EMBODIMENTS
[0016] Hereinafter, exemplary embodiments of the present invention are described with reference
to drawings. The present invention is not limited by the exemplary embodiments.
(FIRST EXEMPLARY EMBODIMENT)
[0017] FIG. 1 is a cross-sectional view of a sealed compressor according to the first exemplary
embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing
a fixing portion between a stator and a bearing of the sealed compressor. FIG. 3 is
a bottom view as viewed from below of the stator and the bearing of the sealed compressor.
[0018] In FIG. 1, the sealed compressor according to this exemplary embodiment is configured
such that compressor body 108 which includes electrically-operated element 104 and
compressive element 106 is housed in sealed container 102 formed by drawing a steel
plate. Compressive element 106 is driven by electrically-operated element 104.
[0019] Compressor body 108 is resiliently supported by suspension springs 120.
[0020] Sealed container 102 is filled with refrigerant gas 122 which is at a pressure substantially
equal to a pressure on a low-pressure side of a refrigeration device (not shown) and
in a relatively low temperature state. For example, refrigerant gas 122 is R600a or
the like which is a hydrocarbon refrigerant having a low global warming potential.
A bottom portion in sealed container 102 is filled with lubrication oil 124.
[0021] Compressive element 106 is formed of: shaft 126; cylinder block 128; piston 130;
connecting portion 132 and the like.
[0022] Shaft 126 includes: eccentric shaft 134; main shaft 136; and oil supply mechanism
138 which supplies oil 124 from a lower end of main shaft 136 which is immersed in
oil 124 to an upper end of eccentric shaft 134.
[0023] Cylinder block 128 is an integral body formed of cylinder 142 which forms compression
chamber 140 and bearing 144 which rotatably and pivotally supports main shaft 136.
[0024] Main shaft 136 has non-sliding portion 146 at a portion of sliding portion 137 which
is in slide contact with inner peripheral surface 164 of bearing 144. Non-sliding
portion 146 is formed by reduction of diameter which narrows an outer diameter of
main shaft 136. Non-sliding portion 146 of main shaft 136 is disposed between an upper
end and a lower end of bearing 144.
[0025] Electrically-operated element 104 is an outer-rotor-type motor formed of: a stator
150; and rotor 152 which surrounds the periphery of stator 150 and is disposed coaxially
with stator 150.
[0026] In rotor 152, permanent magnet 158 is disposed on outer peripheral end portion 156
of disc-like frame 154. Circular cylindrical rotor shaft hole 160 is formed in the
center of frame 154, and an outer periphery of the lower end of main shaft 136 is
fixedly engaged with rotor shaft hole 160 by press-fitting, welding, shrinkage fitting
or the like.
[0027] As can be clearly understood from an enlarged cross-sectional view shown in FIG.
2, fit-on portion 167 and fit-on portion 169 are formed on upper end surface 165 and
lower end surface 166 of stator 150, respectively. Further, an inner diameter of an
inner peripheral surface of a portion of stator 150 except for fit-on portion 167
and fit-on portion 169 of stator 150 is set larger than an inner diameter of fit-on
portion 167 and an inner diameter of fit-on portion 169 so that a predetermined gap
is formed between the inner peripheral surface of stator 150 and outer peripheral
surface 162 of bearing 144.
[0028] As shown in FIG. 3, opening portion 170 which opens in the gap formed between the
inner peripheral surface of the portion of stator 150 except for fit-on portion 167
and fit-on portion 169 and outer peripheral surface 162 of bearing 144 is formed in
fit-on portion 169 of stator 150. Further, stator 150 is fixed by adhesive agent 163
having excellent heat resistance, such as an epoxy-based adhesive agent, which is
injected into the gap formed between outer peripheral surface 162 of bearing 144 and
the inner peripheral surface of stator 150 through opening portion 170.
[0029] Bearing 144 is made of an iron-based material which contains carbon.
[0030] To enhance slidability of bearing 144 with respect to main shaft 136 and seizure
resistance of bearing 144 against main shaft 136 and to ensure strength of bearing
144, bearing 144 is made of an iron-based material where a carbon content is not less
than 1% and not more than 10%.
[0031] When a material for forming bearing 144 is an iron-based material and a carbon content
of the material is not less than 1%, fixing stator 150 to bearing 144 by welding is
difficult because bearing 144 becomes brittle at the time of welding. On the other
hand, with the use of a method where stator 150 is fixed to bearing 144 by an adhesive
agent 163, stator 150 can be fixed to bearing 144 in a stable manner. When a carbon
content is increased, bearing 144 becomes brittle and hence, usually, it is preferable
to set the carbon content to 7% at maximum.
[0032] In a case where stator 150 is fixed to bearing 144 by welding, bearing 144 is made
of an iron-based material having a carbon content of not less than 1% and hence, bearing
144 becomes brittle at the time of welding so that stator 150 cannot be easily fixed
to bearing 144. On the other hand, in this exemplary embodiment, stator 150 is fixed
to bearing 144 by adhesive agent 163 and hence, even when bearing 144 is made of an
iron-based material having a carbon content of not less than 1%, stator 150 can be
fixed to bearing 144 in a stable manner.
[0033] The manner of operation and advantageous effects of the sealed compressor having
the above-mentioned configuration is described hereinafter.
[0034] When electricity is supplied to electrically-operated element 104, an electric current
flows through stator 150 so that a magnetic field is generated, and rotor 152 fixed
to main shaft 136 rotates. Due to rotation of rotor 152, shaft 126 rotates. Then,
piston 130 moves in a reciprocating manner in cylinder 142 by way of connecting portion
132 mounted on eccentric shaft 134 in a rotatable manner. In this manner, compressive
element 106 performs a predetermined compression operation.
[0035] Next, the manner of operation and advantageous effect acquired by fixing stator 150
to outer peripheral surface 162 of bearing 144 by an adhesive agent 163 are described.
[0036] A stator of an outer-rotor-type motor such as stator 150 of the outer-rotor-type
motor according to this exemplary embodiment is usually fixed to outer peripheral
surface 162 of bearing 144 by press-fitting, welding, shrinkage fitting or the like.
Accordingly, inner peripheral surface 164 of bearing 144 at the position where stator
150 is fixed is deformed and hence, a solid contact occurs between sliding portion
137 of main shaft 136 and stator 150 whereby wear is liable to occur between sliding
portion 137 of main shaft 136 and stator 150.
[0037] However, stator 150 of the sealed compressor according to this exemplary embodiment
is fixed to outer peripheral surface 162 of bearing 144 by adhesive agent 163. Accordingly,
unlike the case where stator 150 is fixed to outer peripheral surface 162 of bearing
144 by press-fitting, welding, shrinkage fitting or the like, there is no possibility
that an excessively large force is applied to bearing 144. Accordingly, it is possible
to suppress the generation of distortion on inner peripheral surface 164 of bearing
144.
[0038] Therefore, a solid contact between inner peripheral surface 164 of bearing 144 and
sliding portion 137 of main shaft 136 is avoided and hence, the occurrence of wear
can be prevented. Accordingly, the durability of the sealed compressor can be enhanced.
[0039] Even when adhesive agent 163 is interposed between the inner peripheral surface of
stator 150 and outer peripheral surface 162 of bearing 144, with the formation of
fit-on portion 167 and fit-on portion 169 on stator 150, deterioration of concentricity
between inner peripheral surface 164 of the bearing and the outer peripheral surface
of stator 150 can be suppressed. Therefore, the gap formed between stator 150 and
rotor 152 can be maintained uniformly. Accordingly, efficiency of the operation of
the sealed compressor can be enhanced.
[0040] A predetermined gap is ensured between the inner peripheral surface of the portion
of stator 150 except for fit-on portion 167 and fit-on portion 169 and outer peripheral
surface 162 of bearing 144. Opening portion 170 which opens in the gap formed between
the inner peripheral surface of stator 150 and outer peripheral surface 162 of bearing
144 is formed in fit-on portion 169. With such a configuration, the gap formed between
the inner peripheral surface of stator 150 and outer peripheral surface 162 of bearing
144 can be easily filled with adhesive agent 163 through opening portion 170. Accordingly,
productivity of the sealed compressor is enhanced. Further, stator 150 and bearing
144 can be fixed to each other with certainty.
[0041] In this exemplary embodiment, opening portion 170 is formed in fit-on portion 169
of stator 150. However, opening portion 170 may be formed in fit-on portion 167. Also
in this case, substantially the same advantageous effect can be obtained.
[0042] In this exemplary embodiment, a plurality of opening portions 170 may be formed.
With such a configuration, the gap can be filled with adhesive agent 163 more easily.
[0043] FIG. 4 is another enlarged cross-sectional view showing a fixing portion between
stator 150 and bearing 144 of the sealed compressor according to the first exemplary
embodiment of the present invention. In FIG. 4, a gap into which adhesive agent 163
is filled is disposed on a bearing 144 side. With such a configuration, an electromagnetic
steel plate of stator 150 can be formed into the same shape over the entire fixing
portion.
[0044] FIG. 5 is still another enlarged cross-sectional view showing a fixing portion between
stator 150 and bearing 144 of the sealed compressor according to the first exemplary
embodiment of the present invention. In FIG. 5, an upper side of a paper on which
Fig. 5 is drawn corresponds to an upper side of stator 150. In FIG. 5, fit-on portion
167 is formed on an upper half of stator 150. With such a configuration, the gap can
be easily filled with adhesive agent 163.
[0045] As has been described heretofore, in the sealed compressor of this exemplary embodiment,
electrically-operated element 104 and compressive element 106 which is driven by electrically-operated
element 104 are housed in the inside of sealed container 102. Compressive element
106 includes: shaft 126 formed of main shaft 136 and eccentric shaft 134; and cylinder
block 128 having: bearing 144 which pivotally supports main shaft 136 of shaft 126;
and cylinder 142. Compressive element 106 includes: piston 130 which is movable in
cylinder 142 in a reciprocating manner, and connecting portion 132 which connects
eccentric shaft 134 and piston 130 to each other. Electrically-operated element 104
is an outer-rotor-type motor which includes: stator 150; and rotor 152 which surrounds
the outer periphery of stator 150 and is disposed coaxially with stator 150. Stator
150 is fixed to outer peripheral surface 162 of bearing 144 by adhesive agent 163.
[0046] With such a configuration, the deformation of inner peripheral surface 164 of bearing
144 to which stator 150 is fixed can be reduced. Therefore, a solid contact which
occurs between bearing 144 and main shaft 136 is avoided so that the occurrence of
wear can be prevented. Accordingly, the durability of the sealed compressor can be
enhanced.
[0047] Fit-on portions 167, 169 which are fitted on outer peripheral surface 162 of bearing
144 may be provided to portions of the inner peripheral portion of stator 150. With
such a configuration, even when adhesive agent 163 is interposed between the inner
peripheral portion of stator 150 and outer peripheral surface 162 of bearing 144,
deterioration of concentricity between the inner peripheral portion of bearing 144
and the outer peripheral surface of stator 150 can be suppressed and hence, a gap
formed between stator 150 and rotor 152 can be maintained uniformly. Accordingly,
efficiency of the operation of the sealed compressor can be enhanced.
[0048] Fit-on portions 167, 169 may be formed on upper end surface 165 and lower end surface
166 of stator 150, respectively, and a gap may be formed between a portion of the
inner peripheral portion of stator 150 except for fit-on portions 167, 169 and outer
peripheral surface 162 of bearing 144. With such a configuration, the gap formed between
the inner peripheral portion of stator 150 and outer peripheral surface 162 of bearing
144 can be easily filled with adhesive agent 163. Accordingly, outer peripheral surface
162 of bearing 144 and stator 150 can be fixed to each other with certainty.
[0049] Adhesive agent 163 and oil 124 are insulated from each other by fit-on portions 167,
169. With such a configuration, it is possible to suppress oil 124 from attacking
adhesive agent 163 thus suppressing the deterioration of adhesive agent 163 itself.
It is also possible to suppress the generation of a substance which adversely influences
oil 124 and refrigerant gas 122 from adhesive agent 163. As a result, reliability
of the sealed compressor can be enhanced.
[0050] Opening portion 170 which opens in the gap formed between the inner peripheral portion
of stator 150 and outer peripheral surface 162 of bearing 144 may be formed in fit-on
portions 167, 169. With such a configuration, adhesive agent 163 can be easily injected
into the gap formed between the inner peripheral portion of stator 150 and outer peripheral
surface 162 of bearing 144. Accordingly, productivity of the sealed compressor can
be enhanced.
[0051] A plurality of opening portions 170 may be formed. With such a configuration, the
gap can be more easily filled with adhesive agent 163.
[0052] The gap may be formed on a bearing 144 side. With such a configuration, an electromagnetic
steel plate of stator 15 can be formed into the same shape over the entire fixing
portion.
[0053] Fit-on portion 167 may be formed on an upper half of stator 150 on an eccentric shaft
side. With such a configuration, adhesive agent 163 can be easily filled in the gap.
[0054] Bearing 144 may be made of an iron-based material which contains carbon. With such
a configuration, slidability of bearing 144 with respect to main shaft 136 and seizure
resistance of bearing 144 against main shaft 136 can be enhanced, and strength of
bearing 144 is ensured.
[0055] Bearing 144 may contain not less than 1% and not more than 7% of carbon. With such
a configuration, stator 150 can be fixed to bearing 144 in a stable manner.
(SECOND EXEMPLARY EMBODIMENT)
[0056] FIG. 6 is a schematic view showing a refrigeration device according to a second exemplary
embodiment of the present invention. In the refrigeration device of this exemplary
embodiment, the sealed compressor described in the first exemplary embodiment is mounted
in refrigerant circuit 310. The basic configuration of the refrigeration device is
schematically described.
[0057] In FIG. 6, the refrigeration device includes: body 302 which is formed of a heat
insulating box having an opening equipped with a door; partition wall 308 which partitions
the inside of body 302 into article accommodating space 304 and machine compartment
306, and refrigerant circuit 310 which cools the inside of accommodating space 304.
[0058] Refrigerant circuit 310 is configured such that compressor 312 which is the sealed
compressor described in the first exemplary embodiment, heat-radiator 314, pressure
reduction device 316, and heat absorbing device 318 are annularly connected to each
other by pipes. Heat absorbing device 318 is disposed in the inside of accommodating
space 304 equipped with a blower (not shown). Cooling heat of heat absorbing device
318 is stirred by the blower so that cooling heat circulates the inside of accommodating
space 304 as indicated by an arrow in FIG. 6 whereby accommodating space 304 is cooled.
[0059] The refrigeration device which has been described heretofore includes compressor
312 which is the sealed compressor described in the first exemplary embodiment. That
is, in compressor 312, distortion generated on inner peripheral surface 164 of bearing
144 can be suppressed by fixing stator 150 to outer peripheral surface 162 of bearing
144 by adhesive agent 163. Further, a solid contact between inner peripheral surface
164 of bearing 144 and main shaft 136 is avoided. Therefore, it is possible to provide
a sealed compressor having high durability which can prevent the occurrence of wear.
Accordingly, durability of the refrigeration device can be enhanced.
[0060] As has been described heretofore, the refrigeration device of this exemplary embodiment
includes refrigerant circuit 310 which is formed by annularly connecting compressor
312, heat-radiator 314, pressure reduction device 316, and heat absorbing device 318
to each other by pipes. It is sufficient that compressor 312 is the sealed compressor
described in the first exemplary embodiment. With such a configuration, performance
and durability of the refrigeration device can be enhanced.
INDUSTRIAL APPLICABILITY
[0061] As has been described heretofore, the present invention can provide a sealed compressor
and a refrigeration device having high durability. Accordingly, the present invention
is not limited to household-use electric appliances such as an electric refrigerator
or an air conditioner, and is broadly applicable to a refrigeration device for a business-use
showcase, a vending machine and the like.
REFERENCE MARKS IN THE DRAWINGS
[0062]
- 102
- sealed container
- 104
- electrically-operated element
- 106
- compressive element
- 108
- compressor body
- 120
- suspension spring
- 122
- refrigerant gas
- 124
- oil
- 126
- shaft
- 128
- cylinder block
- 130
- piston
- 132
- connecting portion
- 134
- eccentric shaft
- 136
- main shaft
- 137
- sliding portion
- 138
- oil supply mechanism
- 140
- compression chamber
- 142
- cylinder
- 144
- bearing
- 146
- non-sliding portion
- 150
- stator
- 152
- rotor
- 154
- frame
- 156
- outer peripheral end portion
- 158
- permanent magnet
- 160
- rotor shaft hole
- 162
- outer peripheral surface
- 163
- adhesive agent
- 164
- inner peripheral surface
- 165
- upper end surface
- 166
- lower end surface
- 167, 169
- fit-on portion
- 170
- opening portion
- 302
- body
- 304
- accommodating space
- 306
- machine compartment
- 308
- partition wall
- 310
- refrigerant circuit
- 312
- compressor
- 314
- heat-radiator
- 316
- pressure reduction device
- 318
- heat absorbing device
1. A sealed compressor wherein, an electrically-operated element and a compressive element
driven by the electrically-operated element are housed in a sealed container,
the compressive element includes:
a shaft formed of a main shaft and an eccentric shaft;
a cylinder block having: a bearing which pivotally supports the main shaft of the
shaft; and a cylinder;
a piston which is movable in the cylinder in a reciprocating manner; and
a connecting portion which connects the eccentric shaft and the piston to each other,
the electrically-operated element is an outer-rotor-type motor which includes: a stator;
and a rotor which surrounds an outer periphery of the stator and is disposed coaxially
with the stator, and
the stator is fixed to an outer peripheral surface of the bearing by an adhesive agent.
2. The sealed compressor according to claim 1, wherein a fit-on portion which fits on
the outer peripheral surface of the bearing is formed on a portion of an inner peripheral
portion of the stator.
3. The sealed compressor according to claim 2, wherein the fit-on portion is formed on
an upper end surface and a lower end surface of the stator, and a gap is formed between
an inner peripheral portion of the stator and the outer peripheral surface of the
bearing at portions except for the fit-on portion.
4. The sealed compressor according to claim 3, wherein an opening portion which opens
in the gap formed between the inner peripheral portion of the stator and the outer
peripheral surface of the bearing is formed in the fit-on portion.
5. The sealed compressor according to claim 4, wherein a plurality of the opening portions
is formed.
6. The sealed compressor according to claim 3, wherein the gap is formed on the bearing
side.
7. The sealed compressor according to claim 2, wherein the fit-on portion is formed on
an upper half of the stator on the eccentric shaft side.
8. The sealed compressor according to claim 1, wherein the bearing is made of an iron-based
material which contains carbon.
9. The sealed compressor according to claim 8, wherein the bearing is made of the iron-based
material which contains not less than 1% and not more than 7% of carbon.
10. A refrigeration device comprising a refrigerant circuit formed by annularly connecting
a compressor, a heat-radiator, a pressure reduction device and a heat absorbing device
to each other by pipes, wherein the compressor is the sealed compressor according
to any one of claims 1 to 9.