U.S. patent application number 09/790745 was filed with the patent office on 2001-11-22 for rotary compressor.
Invention is credited to Matsumoto, Kenzo, Okajima, Masazo, Sunaga, Takashi, Takenaka, Manabu.
Application Number | 20010043879 09/790745 |
Document ID | / |
Family ID | 18590173 |
Filed Date | 2001-11-22 |
United States Patent
Application |
20010043879 |
Kind Code |
A1 |
Sunaga, Takashi ; et
al. |
November 22, 2001 |
Rotary compressor
Abstract
A rotary compressor uses a freon without containing chlorine
ions and uses polyol ester as a lubricant or plyvinyl ether as a
base oil for providing a highly reliable rotary compressor, and for
preventing abnormal abrasion. The rotary compressor has a roller
and a vane sliding contact with an outer circumference of the
roller. A sliding contact portion between the vane and the roller
is formed with a curvature Rv, and satisfies T<Rv<Rr, wherein
T is the thickness of the vane and Rr is the curvature of the outer
circumference of the roller.
Inventors: |
Sunaga, Takashi; (Gunma-Ken,
JP) ; Matsumoto, Kenzo; (Gunma-Ken, JP) ;
Takenaka, Manabu; (Gunma-Ken, JP) ; Okajima,
Masazo; (Tochigi-Ken, JP) |
Correspondence
Address: |
J.C. Patents, Inc.
Suite 114
1340 Reynolds Ave.
Irvine
CA
92614
US
|
Family ID: |
18590173 |
Appl. No.: |
09/790745 |
Filed: |
February 22, 2001 |
Current U.S.
Class: |
418/63 ; 418/178;
418/179 |
Current CPC
Class: |
F01C 21/0809 20130101;
F04C 18/3564 20130101; F04C 2210/26 20130101; F04C 2230/92
20130101 |
Class at
Publication: |
418/63 ; 418/178;
418/179 |
International
Class: |
F04C 018/356 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 2000 |
JP |
2000-071619 |
Claims
What claimed is:
1. A rotary compressor, coupled to a freon loop connecting in turn
to the rotary compressor, a condenser, a expansion device and an
evaporator, the rotary compressor using a freon without containing
chlorine ions and using polyol ester as a lubricant or plyvinyl
ether as a base oil, the rotary compressor comprising: a cylinder,
having a freon inlet and a freon outlet; a rotary shaft, having a
crank installed on an axis of the cylinder; a roller, installed
between the crank and the cylinder, and eccentrically rotating; and
a vane, reciprocating within a groove formed in the cylinder, and
sliding contact with an outer circumference of the roller, wherein
a sliding contact portion between the vane and the roller has a
curvature Rv satisfying following formula: T<Rv<Rr wherein T
is the thickness of the vane and Rr is the curvature of the outer
circumference of the roller sliding contact with the vane.
2. The rotary compressor of claim 1, wherein a distance between a
rotation center (O1) of the rotary shaft and a center (O2) of the
roller is an eccentricity (E), an angle .alpha. formed between a
first line (L1) connecting the rotation center (O1) of the rotary
shaft and the center (O2) of the roller, and a second line (L2) in
which the first line (L1) connects the rotation center (O1) of the
rotary shaft and the center (O2) of the roller and the second line
(L2) connects a center (O3) of the curvature Rv of the vane and the
center (O1) of the roller, and a sliding distance, connecting a
first intersection of the first line (L1) with the outer
circumference of the roller and a second intersection of the second
line (L2) with the outer circumference of the roller, wherein the
thickness T, the curvatures Rv, Rr, the eccentricity E, the angle
.alpha., and the sliding distance (ev) satisfy the following
formulae for maintaining a sliding contact surface located at the
sliding contact portion between the vane and the rolled:
T>2.multidot.Rv.multidot.E/(R- v+Rr) sin .alpha.=E/(Rv+Rr)
ev=Rv.multidot.E/(Rv+Rr)
3. The rotary compressor of claim 1, wherein the thickness T, the
curvatures Rv, Rr, the eccentricity E, the angle .alpha., and the
sliding distance (ev) satisfy a formula,
T>[2.multidot.Rv.multidot.E/(Rv+Rr)]+- d, for maintaining the
sliding contact surface located at the sliding contact portion
between the vane and the roller when the rotary compressor is
operated with a large loading, in which L is the height of the
vane, E1, E2 are longitudinal elastic coefficients, .nu.1 and .nu.2
are Poison's ratios for the vane and the roller, .DELTA.P is a
designed pressure, is an effective radius, is a stress from the
vane, d is a distance of an elastic contact surface, wherein .rho.,
.DELTA.P, Fv and d are calculated by following formulae: 4 d = 4 (
1 - v 1 2 E1 + 1 - v 2 2 E2 ) Fv L
Fv=T.multidot.L.multidot..DELTA.P 5 1 = 1 Rv + 1 Rr
4. The rotary compressor of claim 1, wherein when the rotary
compressor is operated with a large loading, the designed pressure
.DELTA.P is 2.98 Mpa for using an HFC407C freon, 4.14 MPa for using
an HFC410A freon, 3.10 MPa for using an HFC404A freon, 1.80 MPa for
using an HFC134a freon.
5. The rotary compressor of claim 1, wherein the vane is composed
of an iron material having a longitudinal elastic coefficient of
between 1.96.times.10.sup.5.about.2.45.times.10.sup.5
N/mm.sup.2.
6. The rotary compressor of claim 5, wherein a top surface of the
vane is further coated with a compound layer composed of an
iron-nitrogen (Fe--N) base, and a diffusion layer with an
iron-nitrogen (Fe--N) base formed under the compound layer by
nitridation.
7. The rotary compressor of claim 5, wherein a top surface of the
vane is further only coated with a compound layer containing an
iron-nitrogen (Fe--N) base.
8. The rotary compressor of claim 5, wherein a top surface of the
vane is further coated with a compound layer containing an
iron-sulfur (Fe--S) base, and a diffusion layer with an
iron-nitrogen (Fe--N) base formed under the compound layer by
nitridation.
9. The rotary compressor of claim 6, wherein the top surface of the
vane is further coated with a compound layer containing an
iron-nitrogen (Fe--N) base, and the diffusion layer with an
iron-nitrogen (Fe--N) base formed under the compound layer by
nitridation, and the compound layer with an iron-nitrogen (Fe--N)
base coated on at least one side surface of the vane is
removed.
10. The rotary compressor of claim 8, wherein a top surface of the
vane is further coated with a compound layer containing an
iron-sulfur (Fe--S) base, and a diffusion layer containing an
iron-nitrogen (Fe--N) base formed under the compound layer by
nitridation, and the compound layer containing an iron-sulfur
(Fe--S) base coated on at least one side surface of the vane is
removed.
11. The rotary compressor of claim 1, wherein the roller sliding
contact with the vane is composed of an iron material having a
longitudinal elastic coefficient between 9.81.times.10.sup.4 and
1.47.times.10.sup.5 N/mm.sup.2.
12. The rotary compressor of claim 1, wherein the stokes of the
base oil is between 20 and 80 mm.sup.2/s at 40.degree. C.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Japanese
application serial no. 2000-071619, filed Mar. 15, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates in general to a rotary compressor
using a freon without containing chlorine ions, and using polyol
ester as a lubricant or plyvinyl ether as a base oil for preventing
abnormal abrasion, and more specifically relates to a structure of
a vane and a roller of a highly reliable rotary compressor.
[0004] 2. Description of Related Art
[0005] Traditionally, the freon used for most compressors within
refrigerators, showcases, vending machines, or air-conditioners for
family and businesses are dichrolrodifluoromethane (R12) and
monochrolrodifluoromethane (R22). The traditional freons R12 and
R22 easily damage the ozone layer when they are released into the
atmosphere. Consequently, use of the traditional freon is
restricted. Damage to the ozone layer of the atmosphere is due to
chlorine components in the freon. Therefore, a natural freon
without chlorine ions, such as HFC freon (for example, R32, R125,
and R134a), phytane type freon (for example, propane and butane
etc.), carbonic acid gas and ammonia etc, is considered to replace
the traditional freon.
[0006] FIG. 1 is a cross-sectional view of a rotary compressor with
two cylinders, FIG. 2 is a diagram for showing a structural
correlation among a roller, a vane and a cylinder, FIG. 3 is a
diagram for showing a vane structure. As shown in FIG. 1, the
rotary compressor 1 comprises a sealed container 10 with an
electromotor and a compressor both installed within the sealed
container 10. The electromotor 20 includes a stator 22 and a rotor
24, both of which are fixed on inner walls of the sealed container
10. A rotary shaft 25 passing through the center of the rotor 24 is
freely rotated to support two plates 33, 34 that are used to seal
the openings of the cylinders 31, 32. A crank 26 is eccentrically
connected to the rotary shaft 25. The cylinders 31, 32 are mounted
between the two plates 33, 34. The axes of the two cylinders 31, 32
are aligned with the axis of the rotary shaft 25. Hereinafter, only
the cylinder 32 is described for simplification. At the sidewall
32b of the cylinder 32, a freon inlet 23 and a freon outlet 25 are
formed respectively.
[0007] Within the cylinder 32, an annular roller 38 is mounted. The
inner circumference 38b of the roller 38 is in contact with the
outer circumference 26a of the crank 26, and the outer
circumference 38a of the roller 38 is in contact with the inner
circumference 32b of the cylinder 32. A vane 40 is mounted on the
cylinder 32 and capable of sliding freely. The front end 40a of the
vane 40 is elastically in contact with the outer circumference 38a
of the roller 38. The front end 40a of the vane 40 and the roller
38 are securely sealed by introducing a compressed freon from the
vane 40. A compressing room 50 is then encompassed by the roller
38, the cylinder 32, and the plate 34 for sealing the cylinder
32.
[0008] When the rotary shaft 25 rotates counterclockwise with
respect to FIG. 2, the roller 38 rotates eccentrically within the
cylinder 32. Therefore, freon gas is introduced into the
compressing room 50 from the inlet 23, compressed and then
exhausted from the outlet 35. During the cycle, a compressing
stress Fv is generated at the contact portion of the vane 40 and
the roller 38.
[0009] According to the traditional structure, the contact surface
(the front end) 40a of the vane 40 in contact with the roller 38 is
an arc shape with a curvature Rv. The curvature Rv is substantially
equal to the width of the vane 40, and about {fraction (1/10)} to
1/3 of the radius of the roller 38. The roller 38 is made of
materials such as cast iron or cast iron alloy, and is formed by a
quenching process. The vane 40 is made of materials such as
stainless steel or tool steel, and can be further coated by
nitridation. In general, the vane 40 is characterized by high
hardness and malleability.
[0010] FIG. 4 shows the contact status between the roller 38 and
the vane, however a cylindrical tube with different curvature can
be used. As shown in FIG. 4, due to the compressing stress Fv of
the vane 40, it is a surface contact, rather than a point contact
or a line contact, between the vane 40 and the roller 38 when they
squeeze each other. The length of an elastic contact surface
between the vane 40 and the roller 38 can be calculated by the
following formula: 1 d = 4 ( 1 - v 1 2 E1 + 1 - v 2 2 E2 ) Fv L
[0011] wherein E1 and E2 are longitudinal elastic coefficients
(kg/cm2) for the vane 40 and the roller 38 respectively, .nu.1 and
.nu.2 are Poisson's ratios for the vane 40 and the roller 38
respectively, L is the height (cm) of the vane 40, Fv is the
compressing stress, .rho. is a effective radius. At the contact
portion, a Hertz stress Pmax (kgf/cm2) is exerted and calculated by
the following formula:
Pmax=4/.pi..multidot.Fv/L/d (9)
[0012] As the structure described above, in order to increase the
durability of the vane a surface process such as a nitridation
process or a CrN ion coating film is performed on the vane of the
rotary compressor using a freon without containing chlorine ions
and using a polyol ester lubricant or plyvinyl ether as a base oil.
However, the durability for nitridation is easily degraded and the
CrN ion film is easily stripped. Furthermore, the nitridation
process or the CrN ion coating film costs high and therefore the
manufacturing cost increases.
SUMMARY OF THE INVENTION
[0013] According to the foregoing description, an object of this
invention is to provide a high reliable rotary compressor using a
freon without containing chlorine ions, and using a polyol ester as
a lubricant or plyvinyl ether as a base oil for preventing abnormal
abrasion between the vane and the roller.
[0014] According to the present invention, it changes the
conventional design that the curvature of the contact surface of
the vane and the roller is substantially equal to the width of the
vane. To maintain the contact surface of the vane and the roller
within an acceptable range, by increasing the curvature of the
contact surface to be larger than the width of the vane, the Hertz
stress is therefore decreased. In addition, the sliding distance
increases for diverging the stress such that the temperature at the
sliding contact portion between the vane and the roller can be
reduced. Accordingly, a coating process with a high cost is not
necessary for the surface of the vane. Namely, even though a low
cost nitridation (NV nitridation, sulphonyl nitridation or radical
nitridation) is used, it can sufficiently reduce the abrasion
between the contact area of the roller and the vane, and further
prevent abnormal abrasion.
[0015] According to the objects mentioned above, the present
invention provides a rotary compressor coupled to a freon loop. The
freon loop is connected to the rotary compressor, a condenser, an
expansion device and an evaporator. The rotary compressor uses a
freon without containing chlorine ions and uses a polyol ester as a
lubricant or polyvinyl ether as a base oil for the lubricant. The
rotary compressor comprises at least a cylinder, a rotary shaft, a
roller and a vane. The cylinder has a freon inlet and a freon
outlet. The rotary shaft has a crank installed on an axis of the
cylinder. The roller is installed between the crank and the
cylinder, and capable of eccentrically rotating. The vane is
capable of reciprocating within a groove formed in the cylinder,
and sliding contact with an outer circumference of the roller. A
sliding contact portion is formed between the vane and the roller,
having a curvature Rv satisfying the following formula:
T<Rv<Rr (1)
[0016] wherein T is the thickness of the vane and Rr is the
curvature of the outer circumference of the roller sliding contact
with the vane.
[0017] As mentioned, a distance between a rotation center (O1) of
the rotary shaft and a center (O2) of the roller is defined as an
eccentricity (E). An angle .alpha. is formed between a first line
(L1) connecting the rotation center (O1) of the rotary shaft and
the center (O2) of the roller, and a second line (L2), in which the
first line (L1) connects the rotation center (O1) of the rotary
shaft and the center (O2) of the roller and the second line (L2)
connects a center (O3) of the curvature Rv of the vane and the
center (O1) of the roller. A sliding distance connects a first
intersection of the first line (L1) with the outer circumference of
the roller and a second intersection of the second line (L2) with
the outer circumference of the roller. The thickness T, the
curvatures Rv, Rr, the eccentricity E, the angle .alpha., and the
sliding distance (ev) satisfy the following formulae for
maintaining a sliding contact surface located at the sliding
contact portion between the vane and the roller:
T>2.multidot.Rv.multidot.E/(Rv+Rr) (2)
sin .alpha.=E/(Rv+Rr) (3)
ev=Rv.multidot.E/(Rv+Rr) (4)
[0018] In addition, the thickness T, the curvatures Rv, Rr, the
eccentricity E, the angle .alpha., and the sliding distance (ev)
satisfy a formula:
T>[2.multidot.Rv.multidot.E/(Rv+Rr)]+d (8)
[0019] for maintaining the sliding contact surface located at the
sliding contact portion between the vane and the roller when the
rotary compressor is operated with a large loading, in which L is
the height of the vane, E1, E2 are longitudinal elastic
coefficients, .nu.1 and .nu.2 are Poison's ratios for the vane and
the roller, .DELTA.P is a designed pressure, is an effective
radius, is a stress from the vane, d is a distance of an elastic
contact surface, wherein .rho., .DELTA.P, Fv and d are calculated
by following formulae: 2 1 = 1 Rv + 1 Rr ( 5 )
Fv=T.multidot.L.multidot..DELTA.P (6) 3 d = 4 ( 1 - v 1 2 E1 + 1 -
v 2 2 E2 ) Fv L ( 7 )
[0020] When the rotary compressor is operated with a large loading,
the designed pressure .DELTA.P is 2.98 Mpa for using an HFC407C
freon, 4.14 MPa for using an HFC410A freon, 3.10 MPa for using an
HFC404A freon, 1.80 MPa for using an HFC134a freon.
[0021] Furthermore, the vane mentioned above is composed of an iron
material having a longitudinal elastic coefficient between
1.96.times.10.sup.5.about.2.45.times.10.sup.5 N/mm.sup.2, and the
roller sliding contact with the vane is composed of an iron
material having a longitudinal elastic coefficient between
9.81.times.10.sup.4 and 1.47.times.10.sup.5 N/mm.sup.2. Preferably,
the stokes of the base oil is between 20 and 80 mm2/s at a
temperature of about 40.degree. C.
[0022] The geometry of the vane and the roller above can be
designed where a top surface of the vane can be further coated with
a compound layer containing an iron-nitrogen (Fe--N) base, and a
diffusion layer with an iron-nitrogen (Fe--N) base formed under the
compound layer by nitridation. The top surface of the vane can be
alternatively only coated with a compound layer containing an
iron-nitrogen (Fe--N) base. The top surface of the vane can also be
further coated with a compound layer containing an iron-sulfur
(Fe--S) base, and a diffusion layer with an iron-nitrogen (Fe--N)
base formed under the compound layer by nitridation.
[0023] Furthermore, the top surface of the vane can be coated with
a compound layer containing an iron-nitrogen (Fe--N) base, and a
diffusion layer containing an iron-nitrogen (Fe--N) base formed
under the compound layer by nitridation, and the compound layer
with an iron-nitrogen (Fe--N) base coated on at least one side
surface of the vane is removed. Alternatively, the top surface of
the vane can be further coated with a compound layer containing an
iron-sulfur (Fe--S) base, and a diffusion layer with an
iron-nitrogen (Fe--N) base is formed under the compound layer by
nitridation, but the compound layer containing an iron-sulfur
(Fe--S) base coated on at least one side surface of the vane is
removed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] While the specification concludes with claims particularly
pointing out and distinctly claiming the subject matter which is
regarded as the invention, the objects and features of the
invention and further objects, features and advantages thereof will
be better understood from the following description taken in
connection with the accompanying drawings in which:
[0025] FIG. 1 is a cross-sectional view of a rotary compressor with
two cylinders;
[0026] FIG. 2 is a diagram for showing a structural correlation
among a roller, a vane and a cylinder in FIG. 1;
[0027] FIG. 3 is a diagram for showing a vane structure in FIG.
1;
[0028] FIG. 4 is a diagram for showing a structural correlation
between a roller and a vane of a rotary compressor in FIG. 1;
[0029] FIG. 5 shows correlations among the center of the rotary
shaft of the rotary compressor, the center of the roller and the
curvature center of the frond end of the vane; and
[0030] FIG. 6 is a freon loop for a rotary compressor in FIG.
1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] FIG. 6 shows a freon loop suitable for the present
invention. The rotary compressor shown in FIG. 1 is also suitable
for the present invention. Referring to FIG. 6, the freon loop is
used for connecting in turn the rotary compressor a (which uses an
HFC freon without containing chlorine ions and uses polyol ester as
a lubricant or plyvinyl ether as a base oil of the lubricant), a
condenser b for condensing the HFC freon, a expansion device c for
reducing the pressure of the HFC freon and an evaporator for
evaporating and liquidizing the HFC freon.
[0032] FIG. 5 shows correlations among the center of the rotary
shaft of the rotary compressor, the center of the roller and the
curvature center of the front end of the vane. As shown in FIG. 5,
the distance between a rotation center (O1) of the rotary shaft 25
and a center (O2) of the roller 38 is defined as an eccentricity
(E). An angle is formed between a first line (L1) and a second line
(L2), wherein the first line (L1) connects the rotation center (O1)
of the rotary shaft and the center (O2) of the roller while the
second line (L2) connects the center (O3) of the curvature Rv of
the vane 40 and the center (O1) of the roller 38. A sliding
distance ev connects a first intersection of the first line (L1)
with the outer circumference 38a of the roller 38 and a second
intersection of the second line (L2) with the outer circumference
38a of the roller 38. The sliding distance ev can be calculated by
the following formula:
ev=Rv(E/(Rv+Rr)
[0033] Next, the curvature Rv of the sliding contact portion
between the vane 40 and the roller 38, the thickness of the vane
40, the curvature Rr of the outer circumference 38a of the roller
38, the eccentricity E, the longitudinal elastic coefficients E1,
E2 of the vane 40 and the roller 38, the Poison's ratios .nu.1,
.nu.2 of the vane 40 and the roller 38 and the designed pressure
.DELTA.P are set.
[0034] In addition, the effective radius .rho., the stress Fv from
the vane 40, the distance of an elastic contact surface d and the
Hertz's stress Pmax are respectively calculated by the formulae
(5), (6), (7) and (9) above
[0035] For example, if the two-cylinder rotary compressor has a
specification that the cylinder is .phi.(inner radius)39
mm.times.H(height)14 mm, the eccentricity E is 2.88 mm, the
exhausting volume is 4.6 cc.times.2, and the parameters T, Rr, E1,
E2, .nu.1, .nu.2 and .DELTA.P are values listed in Table I, then
the values of .rho.Fvdev(T-ev-d)/2Pmax are calculated under the
conditions that the curvature Rv is 3.2 mm4 mm6 mm8 mm10 mm16.6
mm(same as the curvature Rr and flat. The results are shown in
Table I.
1TABLE I exhausting volume 4.6 cc .times. 2, cylinder: .phi.39
.times. H14, eccentricity (E) 2.88 specification 1. height of the
14.00 14.00 14.00 14.00 14.00 14.00 14.00 cylinder (H, mm) 2.
thickness of the 3.20 3.20 3.20 3.20 3.20 3.20 3.20 vane (T, mm) 3.
curvature 3.20 4.00 6.00 8.00 10.00 16.60 Flat (Rv, mm) 4.
curvature 16.60 16.60 16.60 16.60 16.60 16.60 16.60 (Rr, mm) 5.
eccentricity (E) 2.880 2.880 2.880 2.880 2.880 2.880 2.880 6.
longitudinal 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 2.10
.times. 10.sup.6 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 2.10
.times. 10.sup.6 2.10 .times. 10.sup.6 elastic coefficient E1 of
the vane (kgf/cm.sup.2) 7. longitudinal 1.10 .times. 10.sup.6 1.10
.times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6 1.10
.times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6
elastic coefficient E2 of the roller (kgf/cm.sup.2) 8. Poisson's
ratio 0.30 0.30 0.30 0.30 0.30 0.30 0.30 of the vane (.nu.1) 9.
Poisson's ratio 0.30 0.30 0.30 0.30 0.30 0.30 0.30 of the roller
(.nu.1 2) 10. designed 42.00 42.00 42.00 42.00 42.00 42.00 42.00
pressure (.DELTA. P) Result: 1. compressing 18.816 18.816 18.816
18.816 18.816 18.816 18.816 stress of the vane Fv (kgf) 2.
effective radius 0.26828 0.32233 0.4407 0.53984 0.62406 0.83000
1.66000 .rho. (cm) 3. height of the 1.4 1.4 1.4 1.4 1.4 1.4 1.4
vane (L, cm) 4. distance of the 0.00481 0.00527 0.0081 0.00683
0.00734 0.00846 0.01197 elastic contact surface d (mm) 5. sliding
distance 0.93091 1.11845 1.5292 1.87317 2.16541 2.88000 -- (ev) 6.
(T-ev-d)/2 1.1343 1.04051 0.8351 0.66307 0.51693 0.15958 -- (mm) 7.
Hertz pressure 35.57 32.45 27.75 25.07 23.32 20.22 14.30 (Pmax) 8.
percentage w.r.t 100 91 78 70 66 57 40 Pmax = 35.57 (kg f/mm.sup.2,
%)
[0036] As shown in Table I, the percentage of the Hertz's stress
Pmax decreases and the sliding distance ev increases when the
curvature Rv increases under the condition that the Hertz stress is
100% when T=Rv. At Rv=10 mm, the Hertz stress Pmax is 66%, and the
sliding distance ev becomes 2.3-fold. However, at Rv=16.6 mm=Rr,
the Hertz stress Pmax is 57% and (T-ev-d) is about 0.16. At the
time, it is difficult to maintain the sliding contact surface at
the sliding contact portion of the vane 40 and the roller 38.
[0037] In addition, if the two-cylinder rotary compressor has a
specification that the cylinder is .phi.39 mm.times.H14 mm, the
eccentricity E is 2.35 mm, the exhausting volume is 4.6 cc.times.2,
and the parameters T, Rr, E1, E2, .nu.1, .nu.2 and .DELTA.P are
values listed in Table II, then the values of
.rho.Fvdev(T-ev-d)/2Pmax are calculated under the conditions that
the curvature Rv is 3.2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 18.1 mm (same
as the curvature Rr and flat. The results are shown in Table
II.
2TABLE II exhausting volume: 4.6 cc .times. 2, cylinder: .phi.39
.times. H14, eccentricity (E): 2.88 Specification 1. height of the
16.00 16.00 16.00 16.00 16.00 16.00 16.00 cylinder (H, mm) 2.
thickness of the 3.20 3.20 3.20 3.20 3.20 3.20 3.20 vane (T, mm) 3.
curvature 3.20 4.00 6.00 8.00 10.00 16.60 Flat (Rv, mm) 4.
curvature 18.10 18.10 18.10 18.10 18.10 18.10 18.10 (Rr, mm) 5.
eccentricity (E) 2.350 2.350 2.350 2.350 2.350 2.350 2.350 6.
longitudinal elastic coefficient 2.10 .times. 10.sup.6 2.10 .times.
10.sup.6 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 2.10 .times.
10.sup.6 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 E1 of the vane
(kgf/cm.sup.2) 7. longitudinal elastic coefficient 1.10 .times.
10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times.
10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times.
10.sup.6 E2 of the roller (kgf/cm.sup.2) 8. Poisson's ratio of the
vane 0.30 0.30 0.30 0.30 0.30 0.30 0.30 (.nu.1) 9. Poisson's ratio
0.30 0.30 0.30 0.30 0.30 0.30 0.30 of the roller (.nu.1 2) 10.
designed 42.00 42.00 42.00 42.00 42.00 42.00 42.00 pressure
(.DELTA. P) result 1. compressing 21.504 21.504 21.504 21.504
21.504 21.504 21.504 stress of the vane Fv (kgf) 2. effective
radius 0.27192 0.32760 0.4506 0.55479 0.64413 0.90500 1.81000 .rho.
(cm) 3. height of the 1.6 1.6 1.6 1.6 1.6 1.6 1.6 vane (L, cm) 4.
distance of the 0.00484 0.00532 0.0062 0.00692 0.00746 0.00884
0.01250 elastic contact surface d (mm) 5. sliding distance 0.70610
0.85068 1.1701 0.87935 0.76333 0.42456 -- (ev) 6. (T-ev-d)/2
1.24671 1.17439 1.0146 0.37935 0.76333 0.42456 -- (mm) 7. Hertz
pressure 35.50 32.19 27.44 24.73 22.95 19.38 13.69 (Pmax) 8.
percentage w.r.t 100 91 78 70 65 55 39 Pmax = 35.57(kg f/mm.sup.2,
%)
[0038] As shown in Table II, the percentage of the Hertz's stress
Pmax decreases and the sliding distance ev increases when the
curvature Rv increases under the condition that the Hertz stress is
100% when T=Rv. At Rv=10 mm, the Hertz stress Pmax is 65%, and the
sliding distance ev becomes 2.4-fold. However, at Rv=18.1 mm=Rr,
the Hertz stress Pmax is 55% and (T-ev-d) is about 0.42. It is
therefore difficult to maintain the sliding contact surface at the
sliding contact portion of the vane 40 and the roller 38.
[0039] Furthermore, if the two-cylinder rotary compressor has a
specification that the cylinder is .phi.41 mm.times.H16 mm, the
eccentricity E is 3.478 mm, the exhausting volume is 6.6
cc.times.2, and the parameters T, Rr, E1, E2, .nu.1, .nu.2 and
.DELTA.P are values listed in Table III, then the values of
.rho.Fvdev(T-ev-d)/2Pmax are calculated under the conditions that
the curvature Rv is 3.2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 17 mm (same as
the curvature Rr and flat. The results are shown in Table III.
3TABLE III exhausting volume: 6.6 cc .times. 2, cylinder: .phi.41
.times. H16, eccentricity (E): 3.478 Specification 1. height of the
16.00 16.00 16.00 16.00 16.00 16.00 16.00 cylinder (H, mm) 2.
thickness of the 3.20 3.20 3.20 3.20 3.20 3.20 3.20 vane (T, mm) 3.
curvature 3.20 4.00 6.00 8.00 10.00 16.60 Flat (Rv, mm) 4.
curvature 17.00 17.00 17.00 17.00 17.00 17.00 17.00 (Rr, mm) 5.
eccentricity (E) 3.475 3.475 3.475 3.475 3.475 3.475 3.475 6.
longitudinal 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 2.10
.times. 10.sup.6 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 2.10
.times. 10.sup.6 2.10 .times. 10.sup.6 elastic coefficient E1 of
the vane (kgf/cm.sup.2) 7. longitudinal 1.10 .times. 10.sup.6 1.10
.times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6 1.10
.times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6
elastic coefficient E2 of the roller (kgf/cm.sup.2) 8. Poisson's
ratio 0.30 0.30 0.30 0.30 0.30 0.30 0.30 of the vane (.nu.1) 9.
Poisson's ratio 0.30 0.30 0.30 0.30 0.30 0.30 0.30 of the roller
(.nu.1 2) 10. designed 42.00 42.00 42.00 42.00 42.00 42.00 42.00
pressure (.DELTA. P) result 1. compressing 21.504 21.504 21.504
21.504 21.504 21.504 21.504 stress of the vane Fv (kgf) 2.
effective radius 0.26931 0.32381 0.4434 0.54400 0.62963 0.83000
1.66000 .rho. (cm) 3. height of the 1.6 1.6 1.6 1.6 1.6 1.6 1.6
vane (L, cm) 4. distance of the 0.00482 0.00529 0.0062 0.00685
0.00737 0.00856 0.01211 elastic contact surface d (mm) 5. sliding
distance 1.10099 1.32381 1.8130 2.22400 2.57407 3.47500 -- (ev) 6.
(T-ev-d)/2 1.04926 0.93783 0.6931 0.48766 0.31259 -0.13793 -- (mm)
7. Hertz pressure 35.50 32.37 27.66 24.98 23.22 19.98 14.13 (Pmax)
8. percentage w.r.t 100 91 78 70 65 56 40 Pmax = 35.57 (kg
f/mm.sup.2, %)
[0040] As shown in Table III, the percentage of the Hertz's stress
Pmax decreases and the sliding distance ev increases when the
curvature Rv increases under the condition that the Hertz stress is
100% when T=Rv. At Rv=10 mm, the Hertz stress Pmax is 65%, and the
sliding distance ev becomes 2.3-fold. However, at Rv=17 mm=Rr, the
Hertz stress Pmax is 56% and (T-ev-d) is about -0.14. At the time,
it is difficult to maintain the sliding contact surface at the
sliding contact portion of the vane 40 and the roller 38.
[0041] Alternatively, if the two-cylinder rotary compressor has a
specification that the cylinder is .phi.38 mm.times.H15 mm, the
eccentricity E is 4.715 mm, the exhausting volume is 7.65
cc.times.2, and the parameters T, Rr, E1, E2, .nu.1, .nu.2 and
.DELTA.P are values listed in Table IV, then the values of
.rho.Fvdev(T-ev-d)/2Pmax are calculated under the conditions that
the curvature Rv is 4.7 mm, 6 mm8 mm, 10 mm12 mm, 14.5 mm (same as
the curvature Rr and flat. The results are shown in Table IV.
4TABLE IV exhausting volume: 7.65 cc .times. 2, cylinder: .phi.38
.times. H15, eccentricity (E): 4.715 specification 1. height of the
15.00 15.00 15.00 15.00 15.00 15.00 15.00 cylinder (H, mm) 2.
thickness of the 4.70 4.70 4.70 4.70 4.70 4.70 4.70 vane (T, mm) 3.
curvature 4.70 6.00 8.00 10.00 12.00 14.50 Flat (Rv, mm) 4.
curvature 14.50 14.50 14.50 14.50 14.50 14.50 14.50 (Rr, mm) 5.
eccentricity (E) 4.715 4.715 4.715 4.715 4.715 4.715 4.715 6.
longitudinal 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 2.10
.times. 10.sup.6 2.10 .times. 10.sup.6 2.10 .times. 10.sup.6 2.10
.times. 10.sup.6 2.10 .times. 10.sup.6 elastic coefficient E1 of
the vane (kgf/cm.sup.2) 7. longitudinal 1.10 .times. 10.sup.6 1.10
.times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6 1.10
.times. 10.sup.6 1.10 .times. 10.sup.6 1.10 .times. 10.sup.6
elastic coefficient E2 of the roller (kgf/cm.sup.2) 8. Poisson's
ratio 0.30 0.30 0.30 0.30 0.30 0.30 0.30 of the vane (.nu.1) 9.
Poisson's ratio 0.30 0.30 0.30 0.30 0.30 0.30 0.30 of the roller
(.nu.1 2) 10. designed 18.00 18.00 18.00 18.00 18.00 18.00 18.00
pressure (.DELTA. P) result: 1. compressing 12.690 12.690 12.690
12.690 12.690 12.690 12.690 stress of the vane Fv (kgf) 2.
effective radius 0.35495 0.42439 0.51556 0.59184 0.65660 0.72500
1.45000 .rho. (cm) 3. height of the 1.5 1.5 1.5 1.5 1.5 1.5 1.5
vane (L, cm) 4. distance of the 0.00439 0.00480 0.0053 0.00567
0.00597 0.00628 0.00887 elastic contact surface d (mm) 5. sliding
distance 2.30839 2.76000 3.3528 3.84898 4.27019 4.71500 -- (ev) 6.
(T-ev-d)/2 1.19559 0.96976 0.6733 0.4253 0.21461 -0.00781 -- (mm)
7. Hertz pressure 24.53 22.44 20.36 19.00 18.04 17.17 12.14 (Pmax)
8. percentage w.r.t 100 91 83 77 74 70 49 Pmax = 35.57 (kg
f/mm.sup.2, %)
[0042] As shown in Table IV, the percentage of the Hertz's stress
Pmax decreases and the sliding distance ev increases when the
curvature Rv increases under the condition that the Hertz stress is
100% when T=Rv. At Rv=12 mm, the Hertz stress Pmax is 74%, and the
sliding distance ev becomes 1.9-fold. However, at Rv=14.5 mm=Rr,
the Hertz stress Pmax is 70% and (T-ev-d) is about -0.008. It is
therefore difficult to maintain the sliding contact surface at the
sliding contact portion of the vane 40 and the roller 38.
[0043] Therefore, if the curvature of the contact surface of the
vane 40 and the roller 38 is within the range T<Rv<Rv, the
contact surface of the vane 40 and the roller is maintained to
reduce the stress. In addition, the sliding distance increases for
diverging the stress such that the temperature at the sliding
contact portion between the vane and the roller can be reduced,
preventing abnormal abrasion between the vane 40 and the roller
38.
[0044] Accordingly, a high-cost coating process is not required to
be performed on the surface of the vane 40. Namely, even though a
low cost nitridation (NV nitridation, sulphonyl nitridation or
radical nitridation) is used, it can sufficiently reduce the
abrasion between the outer circumference of the roller and the
vane, to further prevent abnormal abrasion.
[0045] Furthermore, according to the present invention, if the
thickness T of the vane 40 is within the range
T>2.multidot.Rv.multidot.E/(Rv+Rr), the contact surface of the
vane 40 and the roller is maintained. In addition, as the thickness
T of the vane 40 is within the range
T>[2.multidot.Rv.multidot.E/(Rv+Rr)]+d, even though the rotary
compressor is operated with a large loading, the contact surface of
the vane 40 and the roller is still securely maintained.
[0046] When the rotary compressor is operated with a large loading,
the designed pressure .DELTA.P is 2.98 Mpa for using an HFC407C
freon, 4.14 MPa for using an HFC410A freon, 3.10 MPa for using an
HFC404A freon, 1.80 MPa for using an HFC134a freon. Therefore,
considering the elastic deformation for each freon operated with a
high loading, it can still maintain the sliding contact surface
between two crest lines of the vane in which one is located at the
sidewall sliding contact with the cylinder and the other is located
at a surface sliding contact with the roller.
[0047] The vane 40 is composed of an iron material having the
longitudinal elastic coefficient between
1.96.times.10.sup.5.about.2.45.times.10.sup.5 N/mm.sup.2. If the
longitudinal elastic coefficient of the vane is too small, the
durability of the vane degrades, and if the longitudinal elastic
coefficient of the vane is too large, it cannot keep an excellent
elastic deformation. Namely, when the longitudinal elastic
coefficient is too large or too small, the stress between the vane
and the roller cannot be reduced and the durability degrades.
[0048] The top surface of the vane is further coated a compound
layer with an iron-nitrogen (Fe--N) base, and a diffusion layer
with an iron-nitrogen (Fe--N) base formed under the compound layer
by nitridation. Alternatively, the top surface of the vane is
further only coated with a compound layer containing an
iron-nitrogen (Fe--N) base. The top surface of the vane can be also
coated with a compound layer containing an iron-sulfur (Fe--S)
base, and a diffusion layer with an iron-nitrogen (Fe--N) base
formed under the compound layer by nitridation. The nitridation and
coating for the vane can increase the durability, which is
disclosed by JP 10-141269, JP 11-217665, JP-5-73918. However, for
the HFC freon, such a nitridation or coating process results in a
poor durability.
[0049] According to the present invention, the curvature Rv of the
sliding contact surface of the vane 40 and the roller 38 is
calculated by the formulae (1).about.(8) above, and then a vane
with curvature Rv is made. The nitridation above can be further
performed on the surface of the vane for obtaining a vane having
high durability.
[0050] In addition, the top surface of the vane is further coated
with a compound layer containing an iron-nitrogen (Fe--N) base, and
a diffusion layer containing an iron-nitrogen (Fe--N) base formed
under the compound layer by nitridation, and a compound layer with
an iron-nitrogen (Fe--N) base coated on at least one side surface
of the vane is removed. Alternatively, the top surface of the vane
is further coated with a compound layer containing an iron-sulfur
(Fe--S) base, and a diffusion layer with an iron-nitrogen (Fe--N)
base formed under the compound layer by nitridation, and the
compound layer with an iron-sulfur (Fe--S) base coated on at least
one side surface of the vane is removed. The nitridation process
changes the crystal structure and therefore changes the dimension
of the vane. Consequently, a portion of the nitridation coating
surfaces of the vane can be further removed.
[0051] The roller sliding contact with the vane is composed of an
iron material having the longitudinal elastic coefficient between
9.81.times.10.sup.4 and 1.47.times.10.sup.5 N/mm.sup.2, for
example. If the longitudinal elastic coefficient of the vane is too
small, the durability of the vane degrades, and if the longitudinal
elastic coefficient of the vane is too large, it cannot keep a
suitable elastic deformation. Namely, when the longitudinal elastic
coefficient is too large or small the stress between the vane and
the roller cannot be reduced and the durability degrades.
[0052] According to the present invention, the stocks for the base
oil formed by the polyol ester or polyvinyl ether are not
restricted. However, the preferred stocks for the base oil is
between about 20 and 80 mm.sup.2/s at a temperature of 40.degree.
C. If the stocks of the base oil is less than 20 mm2/s, it may not
prevent the sliding contact portion between the vane and the roller
from abrasion, while if the stocks of the base oil is greater than
84 mm2/s, it results in a large power consumption and an
uneconomical operation.
[0053] The embodiment described above is not used to limit the
present invention. Various implementations of the embodiment can be
modified to those skilled in the art within the claim scope of the
invention.
[0054] According to the present invention, the rotary compressor
uses a freon without containing chlorine ions, and uses a polyol
ester as a lubricant or plyvinyl ether as a base oil. The contact
surface of the vane and the roller is then maintained within an
acceptable range to reduce the Hertz stress. In addition, the
sliding distance increases for diverging the stress such that the
temperature at the sliding contact portion between the vane and the
roller can be reduced. Thus, these methods prevent abnormal
abrasion.
[0055] Accordingly, a coating process with high cost is not
necessary to be performed on the surface of the vane. Namely, even
though a low cost nitridation (NV nitridation, sulphonyl
nitridation or radical nitridation) is used, it can sufficiently
reduce the abrasion between the outer circumference of the roller
and the vane, and further prevent abnormal abrasion.
[0056] According to the present invention, the contact surface of
the vane and the roller is maintained within an acceptable range
such that even though the rotary compressor is operated with a
large loading, the contact surface of the vane 40 and the roller is
still securely maintained. Considering the elastic deformation for
each freon operated with a high loading, it can still maintain the
sliding contact surface between two crest lines of the vane in
which one is located at the sidewall sliding contact with the
cylinder and the other is located at a surface sliding contact with
the roller.
[0057] In addition, the present invention provides a preferred
range for the longitudinal elastic coefficient of the vane. The
present invention also provides a preferred range for the
longitudinal elastic coefficient of the roller sliding in contact
with the vane. Considering the elastic deformation, the stress
reduces and the durability of the vane increases.
[0058] Furthermore, the present invention provides a preferred
design for the sliding contact surface of the vane and the roller.
The surface of the vane can be further coated by a low cost
nitridation to increase the durability of the vane.
[0059] Moreover, the present invention provides a preferred stocks
for the base oil at a preferable operational temperature for lowing
power consumption and reducing abrasion.
[0060] While the present invention has been described with a
preferred embodiment, this description is not intended to limit our
invention. Various modifications of the embodiment will be apparent
to those skilled in the art. It is therefore contemplated that the
appended claims will cover any such modifications or embodiments as
fall within the true scope of the invention.
* * * * *