U.S. patent application number 14/892052 was filed with the patent office on 2016-04-07 for heat pump apparatus.
The applicant listed for this patent is MITSUBISHI ELECTRIC CORPORPORATION. Invention is credited to Noriaki MATSUNAGA.
Application Number | 20160097569 14/892052 |
Document ID | / |
Family ID | 52431427 |
Filed Date | 2016-04-07 |
United States Patent
Application |
20160097569 |
Kind Code |
A1 |
MATSUNAGA; Noriaki |
April 7, 2016 |
HEAT PUMP APPARATUS
Abstract
To obtain long-term reliability of a heat pump apparatus by
using an insulating material that is less liable to be hydrolyzed
even when a refrigerating machine oil having high hygroscopicity
and a high water content in oil is used, an electric motor of a
compressor includes: a stator fixed to a sealed container with a
winding being wound around the stator through intermediation of an
insulating material; and a rotator surrounded by the stator. The
insulating material includes wholly aromatic liquid crystal
polyester (LCP) containing, as an essential component,
p-hydroxybenzoic acid (PHB) as a monomer and having a main chain of
a molecule formed by linking p-hydroxybenzoic acid and, as another
monomer, only a monomer having a benzene ring, through an ester
bond. A saturated water amount of the refrigerating machine oil is
1% or less at 40 degrees Celsius and a relative humidity of
80%.
Inventors: |
MATSUNAGA; Noriaki; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI ELECTRIC CORPORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
52431427 |
Appl. No.: |
14/892052 |
Filed: |
May 23, 2014 |
PCT Filed: |
May 23, 2014 |
PCT NO: |
PCT/JP2014/063707 |
371 Date: |
November 18, 2015 |
Current U.S.
Class: |
62/324.6 |
Current CPC
Class: |
F25B 49/02 20130101;
F04C 23/008 20130101; C09K 5/044 20130101; F25B 1/04 20130101; F25B
13/00 20130101; F25B 2400/07 20130101; F25B 31/026 20130101; F04C
2240/30 20130101; F25B 31/002 20130101; F25B 2500/11 20130101; F04C
18/356 20130101; H02K 3/30 20130101; C09K 2205/126 20130101; C09K
5/042 20130101; C09K 5/045 20130101 |
International
Class: |
F25B 13/00 20060101
F25B013/00; F25B 49/02 20060101 F25B049/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2015 |
JP |
2013-156732 |
Claims
1. A heat pump apparatus, comprising: a compressor; a condenser; an
expansion mechanism; and an evaporator, the compressor, the
condenser, the expansion mechanism, and the evaporator being
configured to perform a refrigeration cycle, the heat pump
apparatus being configured to perform heat transfer in the
condenser or the evaporator, wherein the compressor includes a
sealed container, a compression mechanism mounted inside the sealed
container, and an electric motor configured to rotate and drive the
compression mechanism, the compression mechanism being configured
to compress refrigerant, and to be lubricated by a refrigerating
machine oil, wherein the electric motor includes a stator fixed to
the sealed container with a winding being wound around the stator
through intermediation of an insulating material, and a rotator
surrounded by the stator, wherein the insulating material includes
a liquid crystal polymer having a main chain of a molecule obtained
by ester bonding, the liquid crystal polymer being obtained by
polycondensation of a total of two or more kinds of monomers, the
monomers containing, as an essential component, p-hydroxybenzoic
acid (PHB) as a monomer component having an ester bond and
containing, as an additive component, one or more kinds of a
following five kinds: 4,4'-biphenol (BP), hydroquinone (HQ),
terephthalic acid (TPA), isophthalic acid (IPA), and
6-hydroxy-2-naphthoic acid (BON6), and wherein a saturated water
amount of the refrigerating machine oil is 0.5% or more and 1% or
less at 40 degrees Celsius and a relative humidity of 80%.
2. The heat pump apparatus of claim 1, wherein a liquid crystal
polymer serving as the insulating material has a latent heat of
crystallization measured by a differential scanning calorimeter
(DSC) of 10 J/g or less.
3. (canceled)
4. The heat pump apparatus of claim 1, wherein the refrigerating
machine oil includes a single substance or a combination of
substances including at least one kind of an ester-based mineral
oil, an ether-based mineral oil, a glycol-based mineral oil, an
alkyl benzene-based mineral oil, a poly-.alpha.-olefin-based
mineral oil, a polyvinyl ether-based mineral oil, a fluorine-based
mineral oil, a naphthene-based mineral oil, and a paraffin-based
mineral oil.
5. The heat pump apparatus of claim 1, wherein the refrigerant
includes a single substance or a combination of substances
including at least one kind of difluoromethane (HFC-32),
1,1,1,2,2-pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane
(HFC-134a), 1,1,1-trifluoroethane (HFC-143a),
2,2-dichloro-1,1,1-trifluoroethane (HFC-123), trifluoromethane
(HFC-23), 1,1-difluoroethane (HFC-152a), 1,1,2 trifluoroethylene
(R1123), trans-1,2-difluoroethylene (R1132(E)), cis-1,2
difluoroethylene (R1132(Z)), 1,1-difluoroethylene (R1132a),
2,3,3,3-tetrafluoro-l-propane (HFO-1234yf), chlorodifluoromethane
(HFC-22), carbon dioxide, ammonia, dimethyl ether, propane (R-290),
isobutane (R-600a), and butane (R-600).
6. A heat pump apparatus, comprising: a compressor; a condenser; an
expansion mechanism; and an evaporator, the compressor, the
condenser, the expansion mechanism, and the evaporator being
configured to perform a refrigeration cycle, the heat pump
apparatus being configured to perform heat transfer in the
condenser or the evaporator, wherein the compressor includes a
sealed container, a compression mechanism mounted inside the sealed
container, and an electric motor configured to rotate and drive the
compression mechanism, the compression mechanism being configured
to compress refrigerant, and to be lubricated by a refrigerating
machine oil, wherein the electric motor includes a stator fixed to
the sealed container with a winding being wound around the stator
through intermediation of an insulating material, and a rotator
surrounded by the stator, wherein the insulating material includes
a liquid crystal polymer having a main chain of a molecule obtained
by ester bonding, the liquid crystal polymer being obtained by
polycondensation of monomers, the monomers containing, as an
essential component, p-hydroxybenzoic acid (PHB) as a monomer
component having an ester bond and containing, as an additive
component, a following five kinds: 4,4'-biphenol (BP), hydroquinone
(HQ), terephthalic acid (TPA), isophthalic acid (IPA), and
6-hydroxy-2-naphthoic acid (BON6), and wherein a saturated water
amount of the refrigerating machine oil is 0.5% or more and 1% or
less at 40 degrees Celsius and a relative humidity of 80%.
7. The heat pump apparatus of claim 6, wherein a liquid crystal
polymer serving as the insulating material has a latent heat of
crystallization measured by a differential scanning calorimeter
(DSC) of 10 J/g or less.
8. The heat pump apparatus of claim 6, wherein the refrigerating
machine oil includes a single substance or a combination of
substances including at least one kind of an ester-based mineral
oil, an ether-based mineral oil, a glycol-based mineral oil, an
alkyl benzene-based mineral oil, a poly-.alpha.-olefin-based
mineral oil, a polyvinyl ether-based mineral oil, a fluorine-based
mineral oil, a naphthene-based mineral oil, and a paraffin-based
mineral oil.
9. The heat pump apparatus of claim 6, wherein the refrigerant
includes a single substance or a combination of substances
including at least one kind of difluoromethane (HFC-32),
1,1,1,2,2-pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane
(HFC-134a), 1,1,1-trifluoroethane (HFC-143a),
2,2-dichloro-1,1,1-trifluoroethane (HFC-123), trifluoromethane
(HFC-23), 1,1-difluoroethane (HFC-152a), 1,1,2 trifluoroethylene
(R1123), trans-1,2-difluoroethylene (R1132(E)), cis-1,2
difluoroethylene (R1132(Z)), 1,1-difluoroethylene (R1132a),
2,3,3,3-tetrafluoro-1-propane (HFO-1234yf), chlorodifluoromethane
(HFC-22), carbon dioxide, ammonia, dimethyl ether, propane (R-290),
isobutane (R-600a), and butane (R-600).
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat pump apparatus, and
more particularly, to a heat pump apparatus including a compressor
with a sealed container accommodating an electric motor, and being
configured to perform a refrigeration cycle.
BACKGROUND ART
[0002] Hitherto, as a heat pump apparatus, there has been provided
an apparatus for performing a refrigeration cycle by sequentially
connecting a compressor for compressing refrigerant, a condenser,
an expansion mechanism, and an evaporator, to thereby transfer
heating energy or cooling energy of the refrigerant to a heat
medium (perform heat transfer) in the condenser or the
evaporator.
[0003] The compressor includes a compression mechanism and an
electric motor for rotating and driving the compression mechanism,
and the compression mechanism and the electric motor are
accommodated in a sealed container. High-pressure and
high-temperature refrigerant compressed by the compression
mechanism is temporarily discharged into the sealed container.
Therefore, the electric motor is exposed to the high-pressure and
high-temperature refrigerant. Further, to smooth the rotation of
the compression mechanism, a machine oil (hereinafter referred to
as "refrigerating machine oil") is stored in the sealed
container.
[0004] The electric motor includes a stator fixed to the sealed
container and a rotator surrounded by the stator and configured to
rotate. The rotator is connected to the compression mechanism. The
stator has a tubular shape and includes a back yoke portion forming
an outer periphery of the stator, a plurality of tooth portions
projecting from the back yoke portion to the center, and a winding
(electric wire) wound around the tooth portions through
intermediation of an insulating material (insulator).
[0005] In addition, as the insulating material (insulator), there
is disclosed an invention using polyphenylene sulfide (PPS) not
having an ester bond (see, for example, Patent Literature 1).
[0006] Further, as the insulating material (insulator), there is
disclosed an invention using polyethylene terephthalate (PET) or
polyethylene naphthalate (PEN) having an ester bond (see, for
example, Patent Literature 2).
CITATION LIST
Patent Literature
[0007] Patent Literature 1: Japanese Unexamined Patent Application
Publication No. 2000-324728 (Page 6, FIG. 2.)
[0008] Patent Literature 2: Japanese Unexamined Patent Application
Publication No. 2001-227827 (Pages 3-4, FIG. 2.)
SUMMARY OF INVENTION
Technical Problem
[0009] PPS not having an ester bond, which is a heat insulator
disclosed in Patent Literature 1, is a thermoplastic crystalline
engineering plastic having a repeating unit of [-ph-S-] obtained by
allowing p-dichlorobenzene and an alkali sulfide to react with each
other under high temperature and high pressure. PPS has
characteristics of relatively excellent heat resistance, no risk of
hydrolysis, high heat resistance, satisfactory moldability, and
high strength and stiffness. However, there are problems in that,
during melt molding, the productivity is degraded owing to a low
solidification speed, burrs are liable to occur, and PPS is
decomposed in a trace amount to generate a sulfur gas, to thereby
corrode a mold.
[0010] On the other hand, PET and PEN each having an ester bond,
which are heat insulators disclosed in Patent Literature 2, and
polybutylene terephthalate (PBT) have hydrolyzability. Therefore,
it is necessary to absorb water in a refrigerant circuit during
circulation of refrigerant in the refrigerant circuit through use
of a refrigerating machine oil having water absorbability, and
there is a problem in that, in the case where the refrigerating
machine oil has high hygroscopicity and a large saturated water
amount, hydrolysis may be caused.
[0011] The present invention has been made to solve the
above-mentioned problems, and a first object thereof is to obtain
long-term reliability of a heat pump apparatus by using an
insulating material that is less liable to be hydrolyzed even when
a refrigerating machine oil having high hygroscopicity and a high
water content in oil is used.
[0012] Further, a second object of the present invention is to
obtain the long-term reliability of the heat pump apparatus at low
cost by using an insulating material having satisfactory
productivity without causing burrs and generating a gas containing
sulfur during a production step of the insulating material, such as
melt molding.
Solution to Problem
[0013] According to one embodiment of the present invention, there
is provided a heat pump apparatus, including: a compressor; a
condenser; an expansion mechanism; and an evaporator, the
compressor, the condenser, the expansion mechanism, and the
evaporator being configured to perform a refrigeration cycle, the
heat pump apparatus being configured to perform heat transfer in
the condenser or the evaporator, in which the compressor includes:
a sealed container; a compression mechanism mounted inside the
sealed container; and an electric motor for rotating and driving
the compression mechanism, the compression mechanism being
configured to compress refrigerant, and to be lubricated by a
refrigerating machine oil, in which the electric motor includes: a
stator fixed to the sealed container with a winding being wound
around the stator through intermediation of an insulating material;
and a rotator surrounded by the stator, in which the insulating
material includes wholly aromatic liquid crystal polyester (LCP)
containing, as an essential component, p-hydroxybenzoic acid (PHB)
as a monomer and having a main chain of a molecule formed by
linking p-hydroxybenzoic acid and, as another monomer, only a
monomer having a benzene ring, through an ester bond, and in which
a saturated water amount of the refrigerating machine oil is 1% or
less at 40 degrees Celsius and a relative humidity of 80%.
Advantageous Effects of Invention
[0014] According to the one embodiment of the present invention,
the insulating material for the electric motor is wholly aromatic
liquid crystal polyester (LCP) containing, as an essential
component, p-hydroxybenzoic acid (PHB) as a monomer component
having an ester bond and having a main chain of a molecule formed
by linking p-hydroxybenzoic acid and, as another monomer, only a
monomer having a benzene ring, through an ester bond. Therefore,
the insulating material has a very low water absorption rate of
0.01% and a degradation in insulation function caused by hydrolysis
is less liable to occur through use of a refrigerating machine oil
having a water content in oil of 1% or less, and hence a heat pump
apparatus excellent in long-term reliability can be provided.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a refrigerant circuit diagram illustrating a basic
configuration of a heat pump apparatus according to Embodiment 1 of
the present invention.
[0016] FIG. 2 is a side sectional view illustrating a part
(compressor) of the heat pump apparatus illustrated in FIG. 1.
[0017] FIG. 3 is a characteristic graph showing hydrolysis
resistance of a part (heat insulator) of the heat pump apparatus
illustrated in FIG. 1.
DESCRIPTION OF EMBODIMENTS
Embodiment 1
[0018] FIG. 1 and FIG. 2 illustrate a heat pump apparatus according
to Embodiment 1 of the present invention. FIG. 1 is a refrigerant
circuit diagram illustrating a basic configuration of the heat pump
apparatus, and FIG. 2 is a side sectional view illustrating a part
of the heat pump apparatus (compressor). Note that, each figure is
illustrated schematically, and the present invention is not limited
to the illustrated forms.
[0019] (Refrigerant Circuit)
[0020] In FIG. 1, a heat pump apparatus 100 includes a compressor 1
for compressing refrigerant, a condenser 3 for condensing the
refrigerant flowing out from the compressor, an expansion mechanism
4 for subjecting the refrigerant flowing out from the condenser 3
to adiabatic expansion, an evaporator 5 for evaporating the
refrigerant flowing out from the expansion mechanism 4, and a
refrigerant pipe 2 that sequentially connects the compressor 1, the
condenser 3, the expansion mechanism 4, and the evaporator 5 to
circulate the refrigerant. Note that, as necessary, a switching
valve (such as a four-way valve) for changing a flow direction of
the refrigerant may be installed in the refrigerant pipe 2, or an
air-sending device for sending air to the condenser 3 and the
evaporator 5 or other devices may be arranged in the refrigerant
pipe 2.
[0021] (Compressor)
[0022] In FIG. 2, the compressor 1 includes a sealed container 10,
a compression mechanism 9 arranged in the sealed container 10, and
an electric motor 6 for rotating and driving the compression
mechanism 9. High-pressure and high-temperature refrigerant
compressed by the compression mechanism 9 is temporarily discharged
into the sealed container 10. Thus, the electric motor 6 is exposed
to the high-pressure and high-temperature refrigerant.
[0023] Further, to smooth the rotation of the compression mechanism
9, an oil reservoir 8 for storing a machine oil (hereinafter
referred to as "refrigerating machine oil") is formed in a bottom
portion of the sealed container 10.
[0024] (Compression Mechanism)
[0025] The compression mechanism 9 includes a sealed space (to be
exact, an inflow port for the inflow of the refrigerant and an
outflow port for the outflow of the refrigerant are formed) formed
by a main bearing (upper bearing) 9m, an auxiliary bearing (lower
bearing) 9s, and a cylinder 9c having both end surfaces in close
contact with the main bearing 9m and the auxiliary bearing 9s, and
an eccentric cylinder 9e arranged in the sealed space.
[0026] A drive shaft 9a is fixed to the eccentric cylinder 9e, and
is rotatably supported by the main bearing 9m and the auxiliary
bearing 9s. Therefore, the eccentric cylinder 9e is rotated
eccentrically by the rotation of the drive shaft 9a.
[0027] Further, a plurality of vanes 9b are arranged in a freely
advancing and retracting manner in a plurality of grooves (not
shown) formed radially in the cylinder 9c, and are pressed against
an outer peripheral surface of the eccentric cylinder 9e. That is,
a plurality of spaces are each formed between a pair of vanes, and
the volume of the space is changed by the rotation of the eccentric
cylinder 9e, to thereby form a compression chamber.
[0028] (Electric Motor)
[0029] The electric motor 6 includes a stator 6s fixed to the
sealed container and a rotator 6r surrounded by the stator 6s and
configured to rotate. The drive shaft 9a forming the compression
mechanism 9 is fixed to the rotator 6r.
[0030] The stator 6s has a tubular shape, and includes a back yoke
portion (not shown) forming an outer periphery of the stator 6s, a
plurality of tooth portions (not shown) projecting from the back
yoke portion to the center, and a winding (electric wire) 6w wound
around the tooth portions through intermediation of an insulating
material (insulator) 7.
[0031] (Refrigerant)
[0032] The refrigerant contains at least one kind of the following
substances (a single substance of the following substances or a
combination of two or more kinds thereof). [0033] Difluoromethane
(HFC-32) [0034] 1,1,1,2,2-Pentafluoroethane (HFC-125) [0035]
1,1,1,2-Tetrafluoroethane (HFC-134a) [0036] 1,1,1-Trifluoroethane
(HFC-143a) [0037] 2,2-Dichloro-1,1,1-trifluoroethane (HFC-123)
[0038] Trifluoromethane (HFC-23) [0039] 1,1-Difluoroethane
(HFC-152a) [0040] 1,1,2 Trifluoroethylene (R1123) [0041] trans-1,2,
Difluoroethylene (R1132(E)) [0042] cis-1,2 Difluoroethylene
(R1132(Z)) [0043] 1,1 Difluoroethylene (R1132a) [0044]
2,3,3,3-Tetrafluoro-1-propane (HFO-1234yf) [0045]
Chlorodifluoromethane (HFC-22) [0046] Carbon dioxide [0047]
Ammonia
[0048] Dimethyl ether [0049] Propane (R-290) [0050] Isobutane
(R-600a) [0051] Butane (R-600)
[0052] (Refrigerating Machine Oil)
[0053] The refrigerating machine oil is stored in the oil reservoir
8 of the sealed container 10, and is at least one kind of an
ester-based mineral oil, an ether-based mineral oil, a glycol-based
mineral oil, an alkyl benzene-based mineral oil, a
poly-.alpha.-olefin-based mineral oil, a polyvinyl ether-based
mineral oil, a fluorine-based mineral oil, a naphthene-based
mineral oil, and a paraffin-based mineral oil. That is, the
refrigerating machine oil is a single substance of any one kind
thereof or a combination of any two or more kinds thereof.
[0054] (Insulating Material)
[0055] The insulating material 7 is formed of "LCP". LCP is a
collective term of polymers that exhibit liquid crystallinity
during melting. LCP has a plurality of molecular structures, and
the heat resistance and strength thereof are not constant because
the heat resistance and strength depend on monomers for forming
LCP.
[0056] LCP for forming the insulating material 7 is a thermoplastic
resin obtained by copolymerization (polycondensation) of a total of
two or more components, the components containing, as an essential
component, p-hydroxybenzoic acid (PHB) as a monomer component and
having added thereto at least one of the following additive
components.
[0057] That is, the additive component is at least one component of
the following five kinds. [0058] 4,4'-Biphenol (BP) [0059]
Hydroquinone (HQ) [0060] Terephthalic acid (TPA) [0061] Isophthalic
acid (IPA) [0062] 6-Hydroxy-2-naphthoic acid (BON6)
[0063] For example, the insulating material 7 is formed of "LCP-A"
that is a two-component system of PHB and BON6 or "LCP-B" obtained
by polycondensation of monomers (PHB, BP, HQ, TPA, IPA, BON6) of a
six-component system including the essential component and all the
additive components.
TABLE-US-00001 TABLE 1 Water Latent heat Kind of Raw material
monomer of LCP absorption of resin PHB BP BON6 HQ TPA IPA rate
crystallization LCP-A .smallcircle. -- .smallcircle. -- -- -- 0.01%
3 J/g LCP-B .smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. 0.01% 3 J/g PBT -- -- -- -- -- -- 0.10%
30 J/g
[0064] In Table 1, the absorption rate and the latent heat of
crystallization of LCP-A and LCP-B are smaller values than those of
PBT alone (polybutylene terephthalate). Thus, LCP-A and LCP-B each
have the following characteristics. The heat resistance and
extractability are excellent, and the flow characteristics in the
case of being thin is excellent by virtue of a low melt viscosity
during molding. The heat transfer amount from a molten state to a
solidified state is small, and hence the solidification speed is
very high and burrs are less liable to occur during a production
step.
[0065] Further, LCP-A and LCP-B each have a latent heat of
crystallization measured by a differential scanning calorimeter
(DSC) of 10 J/g or less, and hence their solidification speeds are
high and burrs are less liable to occur during their production
steps. Thus, LCP-A and LCP-B each have features of enabling
high-cycle molding and having satisfactory productivity.
[0066] Specifically, although LCP is hydrolyzed in terms of a
molecular structure owing to the ester bond, LCP is not in a state
in which molecules are tangled in a rubber form as in an ordinary
resin but a liquid crystal resin in which stiff molecules are
linearly oriented densely. Thus, LCP has a very low water
absorption rate. The water absorption rate of an engineering
plastic, such as PBT, is "0.1%", whereas the water absorption rate
of LCP is "0.01% (after immersion in water at 23 degrees Celsius
for 24 hours), which is a value smaller by a digit or more than the
former.
[0067] Thus, LCP for forming the insulating material 7 is excellent
in heat resistance and extractability, and hence the stability
thereof is high with respect to any of the above-mentioned
refrigerating machine oils and refrigerant.
[0068] FIG. 3 is a characteristic graph showing hydrolysis
resistance of a part (heat insulator) of the heat pump apparatus
according to Embodiment 1 of the present invention.
[0069] In FIG. 3, the vertical axis represents a tensile strength
retention ratio (ratio of strength after a test with respect to the
initial strength), and the horizontal axis represents a water
content in oil of the refrigerating machine oil, that is, water
content in oil (%) at 40 degrees Celsius and a relative humidity of
80%.
[0070] Ether oil having high hygroscopicity is used as the
refrigerating machine oil, and R32 refrigerant is used as the
refrigerant. LCP-A, LCP-B, and PBT for comparison are each immersed
in a container in which the ether oil and R32 refrigerant are put
at 150 degrees Celsius for 500 hours to determine a tensile
strength retention ratio.
[0071] In this case, as is apparent from FIG. 3, the tensile
strength retention ratio of PBT, which is a comparative material,
is only about 60%, even when the water content in oil is 0.1%.
Further, when the water content in oil reaches 0.2%, the tensile
strength retention ratio decreases drastically. When the water
content in oil reaches 0.5% or more, the tensile strength retention
ratio is a low value of 10%.
[0072] On the other hand, each tensile strength retention ratio of
LCP-A and LCP-B of the present invention decreases along with an
increase in water content in oil. However, the tensile strength
retention ratio is kept at 70% or more when the saturated water
amount falls within a range of 2% or less.
[0073] Thus, LCP-A and LCP-B of the present invention keep a
sufficient insulation function as long as the saturated water
amount of the refrigerating machine oil is 2% or less, and can
provide the electric motor 6 with high reliability and the heat
pump apparatus 100 with high reliability.
[0074] Note that, in the foregoing, LCP-A that is a two-component
system and LCP-B that is a six-component system exhibit similar
hydrolysis resistance characteristics. Thus, the similar hydrolysis
resistance characteristics are obtained in the case of monomers of
all the combinations of a three-component system and monomers of
all the combinations of a four-component system or a five-component
system as long as PHB is included.
[0075] Note that, LCP is a resin that exhibits an intermediate
state between a solid and a liquid in a molten state, that is, a
resin in a state in which a number of rod-like molecules are
arranged, and has a feature of being solidified in a state close to
the molten state. Specifically, LPC is excellent in hydrolyzability
for the following reason. LPC is subjected to a shearing force
caused by injection or extrusion in a molten state, and molecules
are oriented further densely, with the result that water molecules
are prevented from entering or permeating a gap between the
molecules. Thus, only with LCP, the hydrolyzability is
significantly advantageous with respect to an ordinary resin having
an ester bond, such as PET or PBT.
[0076] Further, LCP is wholly aromatic LCP formed of a molecule
having a strong skeleton in which all the six monomer components
themselves have aromatic rings, and hence is less liable to be
hydrolyzed.
REFERENCE SIGNS LIST
[0077] 1 compressor 2 refrigerant pipe 3 condenser 4 expansion
mechanism 5 evaporator 6 electric motor 6r rotator 6s stator 6w
winding 7 insulating material 8 oil reservoir 9 compression
mechanism 9a drive shaft 9b vane 9c cylinder 9e eccentric
cylinder
[0078] 9m main bearing (upper bearing) 9s auxiliary bearing (lower
bearing) 10 sealed container 100 heat pump apparatus
* * * * *