U.S. patent application number 09/953691 was filed with the patent office on 2002-10-24 for swash plate type compressor.
Invention is credited to Fukanuma, Tetsuhiko, Kawaguchi, Masahiro, Kayukawa, Hiroaki.
Application Number | 20020155004 09/953691 |
Document ID | / |
Family ID | 18766315 |
Filed Date | 2002-10-24 |
United States Patent
Application |
20020155004 |
Kind Code |
A1 |
Fukanuma, Tetsuhiko ; et
al. |
October 24, 2002 |
Swash plate type compressor
Abstract
A swash plate type compressor that has a pair of shoes between a
swash plate and a piston. The motion of the swash plate is
transmitted to the piston through the shoes. Each piston
reciprocates according to the transmitted monitor. A coating is
applied to each surface of the swash plate to contact the
corresponding shoe. The surface of each coating is flat. Each shoe
includes a substantially flat surface, which contacts the swash
plate, and semi-spherical portion, which is fitted to the piston.
Each substantially flat surface includes a main chamfered portion
near the periphery. The inclination angle of each main chamfered
portion will respect to the corresponding coating in a
predetermined angle or less. Each coating contacts one of the
substantially flat surfaces. The maximum distance between each main
chamfered portion and the corresponding coating is equal to or less
than the thickness of the corresponding coating.
Inventors: |
Fukanuma, Tetsuhiko;
(Kariya-shi, JP) ; Kayukawa, Hiroaki; (Kariya-shi,
JP) ; Kawaguchi, Masahiro; (Kariya-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
345 Park Avenue
New York
NY
10154
US
|
Family ID: |
18766315 |
Appl. No.: |
09/953691 |
Filed: |
September 17, 2001 |
Current U.S.
Class: |
417/71 |
Current CPC
Class: |
F05C 2251/14 20130101;
F05C 2253/20 20130101; F05C 2253/12 20130101; F04B 27/0886
20130101 |
Class at
Publication: |
417/71 |
International
Class: |
F01B 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2000 |
JP |
2000-281698 |
Claims
1. A swash plate type compressor, wherein at least a pair of shoes
is provided between a swash plate and a piston, wherein motion of
the swash plate is transmitted to the piston through the shoes, and
the piston reciprocates according to the transmitted motion,
wherein a coating in applied to each of two surfaces of the swash
plate to contact the shoes, respectively, and the surface of each
coating is flat, wherein each shoe includes a substantially flat
surface and a semi-spherical portion, and each substantially flat
surface contacts the swash plate, and each semi-spherical portion
is fitted to the piston, wherein the substantially flat surface of
each shoe includes a main chamfered portion, and the main chamfered
portion is provided near the periphery of the substantially flat
surface, and the inclination angle of each main chamfered portion
with respect to the corresponding coating is a predetermined angle
or less, wherein each coating contacts one of the substantially
flat surface, and the maximum distance between each main chamfered
portion and the corresponding coating is equal to or less than the
thickness of the corresponding coating.
2. The compressor according to claim 1, wherein each shoe includes
a sub-chamfered portion, which surrounds the corresponding main
chamfered portion, wherein the sub-chamfered portion is joined to
the main chamfered portion, and wherein the inclination angle of
the sub-chamfered portion with respect to the corresponding coating
is greater than the predetermined angle.
3. The compressor according to claim 1, wherein the predetermined
angle of the inclination angle of each main chamfered portion is 20
degrees.
4. The compressor according to claim 1, wherein each coating is
formed of a metal layer and a resin layer, wherein the resin layer
includes solid lubricant, and the resin layer is formed on the
metal layer.
5. The compressor according to claim 4, wherein the swash plate is
made of iron-based material, and the metal layers are made of
aluminum-based or copper-based material.
6. The compressor according to claim 1, wherein the distance
between each main chamfered portion and the corresponding coating
gradually increases from the center of the corresponding
substantially flat surface in a radially outward direction.
7. The compressor according to claim 1, wherein each substantially
flat surface is an arched surface, the vertex of which is at the
center of the corresponding substantially flat surface.
8. The compressor according to claim 4, wherein the metal layers
are formed of metal that is softer than the material of the swash
plate.
9. A swash plate type compressor, wherein at least a pair of shoes
is provided between a swash plate and a piston, wherein the motion
of the swash plate is transmitted to the piston through the shoes,
and the piston reciprocates according to the transmitted motion,
wherein a coating is applied to each of two surfaces of the swash
plate to contact the shoes, respectively, wherein each coating
includes a metal layer and a resin layer found on the metal layer,
wherein the resin layer includes solid lubricant, wherein each shoe
includes a substantially flat surface and a semi-spherical portion,
and each substantially flat surface contacts the swash plate, and
each semi-spherical portion is fitted to the piston, wherein the
substantially flat surface of each above includes a main chamfered
portion and a sub-chamfered portion, the main chamfered portion
being provided near the periphery of each substantially flat
surface, wherein the sub-chamfered portion surrounds the main
chamfered portion and is smoothly joined to the main chamfered
portion, wherein the first inclination angle of each main chamfered
portion with respect to the corresponding coating is a
predetermined angle or less, wherein each coating contacts one of
the substantially flat surfaces, wherein the second inclination
angle of each sub-chamfered portion with respect to the
corresponding coating is greater than the predetermined angle, and
wherein the maximum distance between each main chamfered portion
and the corresponding coating is equal to or less than the
thickness of the corresponding coating.
10. The compressor according to claim 9, wherein the predetermined
angle of the first inclination angle of each main chamfered portion
is 20 degrees.
11. The compressor according to claim 9, wherein the swash plate is
made of iron-based material, and the metal layers are made of
aluminum-based or copper-based material.
12. The compressor according to claim 9, wherein the distance
between each main chamfered portion and the corresponding coating
gradually increases from the center of the corresponding
substantially flat surface in a radially outward direction.
13. The compressor according to claim 9, wherein each substantially
flat surface is an arched surface, the vertex of which is at the
center of the corresponding substantially flat surface.
14. The compressor according to claim 9, wherein the metal layers
are formed of metal that is softer than the material of the swash
plate.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a swash plate type
compressor. More particularly, the present invention relates to a
swash plate type compressor that has a swash plate, on which
coatings are formed, and pairs of shoes. Each shoe is located
between the swash plate and one of the pistons. The coatings are
applied to the area of the swash plate that contacts the shoes.
Each shoe has a substantially flat surface and a semi-spherical
portion. Each substantially flat surface contacts the swash plate,
which integrally rotates with a rotary shaft. Each semi-spherical
portion is fitted to one of two concave recesses of the
corresponding piston. The rotational force of the swash plate is
transmitted to the pistons through the shoes to drive the
pistons.
[0002] Japanese Examined Patent publication No. 61-1636 and
Japanese Unexamined Patent Publication No. 11-193780 disclose a
swash plate type compressor that has pistons, which reciprocate in
accordance with the rotation of a swash plate that integrally
rotates with a rotary shaft. A shoe is provided between the front
peripheral portion of the swash plate and each piston and between
the rear peripheral portion of tho swash plate and each piston. The
shoes transmit force from the swash plate to the pistons. The shoes
slide along the rotating swash plate. Thus, the shoes, which are
made of iron-based material, may wear out or seize. Therefore, it
is necessary to improve the sliding performance of the swash plate
with respect to the shoes.
[0003] According to the compressor described in Japanese Examined
Patent Publication No. 11-1636, the flat surface of each
hemispheric shoe is arched outward. The radius of curvature of the
arched portions is very large. A first chamfered portion and a
second chamfered portion are formed near the periphery of each
arched surface. The inclination angle of the second chamfered
portion, which is radially inward of the first chamfered portion,
is smaller than the inclination angle of the first chamfered
portion. The first and second chamfered portions drew lubricant
from the peripheral portion of the swash plate, which enters
between each shoe and the swash plate. This improves the sliding
performance of the swash plate with respect to the shoes.
[0004] According to Japanese Unexamined Patent Publication
11-193780, coating, which has high sliding performance, is applied
to the swash plate to further improve the sliding performance of
the swash plate with respect to the shoes. The coating is applied
to the front and rear peripheral portions of the swash plate, which
contact the shoes.
[0005] According to Japanese Unexamined Patent Publication No.
6-336978, a filter is provided in a passage for refrigerant gas.
The filter is provided for filtering foreign particles such as
grinding chips of parts or wear particles in the compressor and an
external refrigerant circuit. The filter only catches foreign
particles that are more than certain size to avoid clogging of the
filter. Thus, the foreign particles that pass through the filter
may be caught between the swash plate and the shoes. Therefore, in
the compressor that has the coated swash plate, the coating may be
damaged depending on the size of foreign particles caught between
the swash plate and the shoes. When the coating is damaged, the
sliding performance of the coating decreases.
SUMMARY OF THE INVENTION
[0006] The objective of the present invention is to prevent foreign
particles from adversely affecting or decreasing the effectiveness
of a coating.
[0007] To achieve the foregoing objective, the present invention
provides a swash plate type compressor that has at least a pair of
shoes between a swash plate and a piston. Motion of the swash plate
is transmitted to the piston through the shoes. The piston
reciprocates according to tho transmitted motion. A coating is
applied to each of two surfaces of the swash plate to contact the
shoes, respectively. The surface of each coating is flat. Each shoe
includes a substantially flat surface and a semi-spherical portion.
Each substantially flat surface contacts the swash plate. Each
semi-spherical portion is fitted to the piston. The substantially
flat surface of each shoe includes a main chamfered portion. The
main chamfered portion is provided near the periphery of the
substantially flat surface. The inclination angle .theta.1 of each
main chamfered portion with respect to the corresponding coating is
a predetermined angle or less. Each coating contacts one of the
substantially flat surface. The maximum distance .beta. between
each main chamfered portion and the corresponding coating is equal
to or less than the thickness D of the corresponding coating.
[0008] Other aspects and advantages of the invention will become
apparent from the following description, taken in conjunction with
the accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention, together with objects and advantages thereat,
may best be understood by reference to the following description of
the presently preferred embodiments together with the accompanying
drawings in which:
[0010] FIG. 1(a) is a cross-sectional view of a compressor
according to a first embodiment.
[0011] FIG. 1(b) is an enlarged partial cross-sectional view of a
pair of shoes and a swash plate;
[0012] FIG. 2 is an enlarged partial cross-sectional view of the a
shoe the swash plate;
[0013] FIG. 3 illustrates a diagrammatic profile of a shoe;
[0014] FIG. 4 is an enlarged partial cross-sectional view of a
second embodiment;
[0015] FIG. 5 is an enlarged partial cross-sectional view of a
third embodiment; and
[0016] FIG. 6 is an enlarged partial cross-sectional view of a
fourth embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] A first embodiment of the present invention will be
described with reference to FIGS. 1 to 3.
[0018] FIG. 1(a) illustrates the internal structure of a swash
plate type variable displacement compressor. A rotary shaft 13 is
supported by a front housing 12, which defines a control pressure
chamber 121, and a cylinder block 11. The rotary shaft 13 is driven
by an external drive source such as an engine of a vehicle. A rotor
14 is secured to the rotary shaft 13. A swash plate 15 is pivotally
supported by the rotary shaft 13 to slide in the axial direction. A
support body 151 is integrally molded with the swash plate 15 and
is made of iron-based material. A pair of guide pins 16 (only one
guide is shown in FIG. 1) are secured to the support body 151. Each
guide pin 16 is slidably fitted in a corresponding guide hole 141,
which is formed in the rotor 14. The guide holes 141 and the guide
pins 16 cooperate with each other. This permits the swash plate 15
to tilt with respect to the axis of the rotary shaft 13 and to
rotate integrally with the rotary shaft 13. The tilting motion of
the swash plate 15 is guided by the guide holes 141, the guide pins
16, and the rotary shaft 13.
[0019] The inclination angle of the swash plate 15 is changed by
controlling the pressure in the control pressure chamber 121. When
the pressure in the control pressure chamber 121 increases, the
inclination angle of the swash plate 15 decreases. When the
pressure in the control pressure chamber 121 decreases, the
inclination angle of the swash plate 15 increases. Refrigerant in
the control pressure chamber 121 flows to a suction chamber 191 in
a rear housing 19 through a pressure release passage, which is not
shown in the figures. Refrigerant in a discharge chamber 192 in the
rear housing 19 is supplied to the control pressure chamber 121
through a pressure supply passage, which is not shown in the
figures. A displacement control valve 25 is provided on the
pressure supply passage. The displacement control valve 25 controls
the flow rate of refrigerant supplied to the control pressure
chamber 121 from the discharge chamber 192. When the flow rate of
refrigerant is supplied to the control pressure chamber 121 from
the discharge chamber 192 increases, the pressure in the control
pressure chamber 121 increases. When the flow rate of refrigerant
supplied to the control pressure chamber 121 from the discharge
chamber 192 decreases, the pressure in the control pressure chamber
121 decreases. Accordingly, the displacement control valve 25
controls the inclination of the swash plate 15.
[0020] When the swash plate 15 contacts the rotor 14, the swash
plate 15 is at the maximum inclination angle. When a snap ring 24
on the rotary shaft 13 contacts the swash plate 15, the swash plate
15 is at the minimum inclination angle.
[0021] Cylinder bores 111 are located around the rotary shaft 13 in
the cylinder block 11 (only two cylinder boxes are shown in FIG.
1(a)). A piston 17 is accommodated in each cylinder bore 111. A
holder 171 is formed in each piston 17 and a pair of concave
recesses 172, 173 are formed in the holder 171. As shown in FIG.
1(b), the rear concave recess 172 is coupled to a rear hemispheric
shoe 18A and the front concave recess 173 is coupled to a front
hemispheric shoe 18B. The hemispheric shoes 18A, 18B cannot be
removed from the respective concave recesses 172, 173. Each shoe
18A, 18B is made of iron-based material.
[0022] The motion of the swash plate 15 is converted into linear
reciprocation of the pistons 17 by the shoes 18A, 18B. Thus, each
piston 17 reciprocates in the corresponding cylinder bore 111. The
rear shoe 18A slides along the contact surface 30 of the swash
plate 15. The front shoe 18B slides along the opposite contact
surface 31 of the swash plate 15.
[0023] When one of the pistons 17 moves from the top dead center to
the bottom dead center in the associated cylinder bore 111
(movement from right to left in FIG. 1(a)), refrigerant in the
section chamber 191 flows into the associated cylinder bore 111
from the corresponding suction port 201 in a first valve plate 20
and causes a corresponding suction valve 211 on a second valve
plate 21 to open.
[0024] When one of the pistons 17 moves from the bottom dead center
to the top dead center in the associated cylinder bore 111
(movement from left to right in FIG. 1(a)), refrigerant in the
associated cylinder bore 111 is then discharged from a
corresponding discharge port 202 on the first valve plate 20 to the
discharge chamber 192 and causes a corresponding discharge valve
221 on a third valve plate 22 to open. Retainers 231 are formed on
a fourth valve plate 23 to limit the opening degree of the
discharge valves 221.
[0025] The discharge chamber 192 and the suction chamber 191 are
connected by an external refrigerant circuit 26. Refrigerant in the
discharge chamber 192 flows to the suction chamber 191 through the
external refrigerant circuit 26, which includes a condenser 27, an
expansion valve 28, an evaporator 29.
[0026] As shown in FIGS. 1(a) and 1(b), coatings 32, 33 are formed
on a rear peripheral portion 152 and a front peripheral portion 153
of the swash plate 15, respectively. The rear peripheral portion
152 and the front peripheral portion 153 are contact areas. Each
coating 32, 33 has two layers. The two layers include metal layers
321, 331, which are respectively formed on the rear peripheral
portion 152 and the front peripheral portion 153, and resin layers
322, 332, which are respectively formed on the metal layers 321,
331. Thus, the surfaces of the resin layers 322, 332 are contact
surfaces 30, 31 that contact the shoes 18A, 18B respectively.
[0027] The metal layers 321, 331 are respectively formed on the
peripheral portions 152, 153. The metal layers 321, 331 are formed
of aluminum-based material, which is mainly made of aluminum that
contains silicon. The metal layers 321, 331 may be formed of
copper-based material. Each resin layer 322, 332 is formed on the
corresponding metal layer 321, 331. Each resin layer 322, 332 is
formed of resin material such as polyamideimide, in which solid
lubricant, such as molybdenum disulfide and graphite, is dispersed.
Thus, each coating 32, 33 is made of much softer material than the
material of the swash plate 15. The thickness of each metal layer
321, 331 is approximately 60 to 70 .mu.m. The thickness of each
resin layer 322, 332 is approximately 10 to 20 .mu.m. Therefore,
the total thickness D of each coating 32, 33 is approximately 70 to
90 .mu.m.
[0028] As shown in FIG. 2, each shoe 18A, 18B has a substantially
flat surface 34 and a semi-spherical portion 35. The substantially
flat surface 34 contacts the swash plate 15. The semi-spherical
portion 35 is fitted to the corresponding concave recess 172, 173
of the associated piston 17. Each substantially flat surface 34
includes an arched surface 341 and a main chamfered portion 342.
The radius of curvature of the arched surface 341 is very large. An
annular main chamfered portion 342 is formed on the periphery of
the substantially flat surface 34 such that the main chamfered
portion 342 and the arched surface 341 are smoothly joined to each
other. An annular sub-chamfered portion 36 is formed around the
main chamfered portion 342 such that the sub-chamfered portion 36
and the main chamfered portion 342 are smoothly joined to each
other. The distance between each main chamfered portion 342 and the
corresponding coating 32, 33 gradually increases from the center of
the corresponding substantially flat surface 34 in a radially
outward direction. Each substantially flat surface 34 is an arched
surface, the vertex P of which is at the center of the
corresponding substantially flat surface 34.
[0029] FIG. 3 illustrates a diagrammatic profile of one of the
shoes. In FIG. 3, the profile of the substantially flat surface 34
and the sub-chamfered portion 36 are enlarged in the direction
perpendicular to the substantially flat surface 34 for the purpose
of illustration. Point P represents the center of the substantially
flat surface 34. Line H represents a flat surface that contacts the
center P of the substantially flat surface 34. The average of first
inclination angles .theta.1 of the main chamfered portions 342 of
the shoes with respect to the corresponding flat surface H is
approximately 2 to 7 degrees. The average of second inclination
angles .theta.2 of the sub-chamfered portions 36 of the shoes with
respect to the corresponding flat surface H is approximately 40
degrees. The inclination angles .theta.1, .theta.2 represent the
inclinations of line segments, that radially follow the main
chamfered portion 342 and the sub-chamfered portion 36,
respectively, with respect to the flat surface H. The maximum
distance .alpha. between the flat surface H and the arched surface
341 is approximately 2 to 7 .mu.m. The maximum distance .beta.
between the flat surface H and the main chamfered portion 342 is
approximately 10 .mu.. The maximum distance .gamma. between the
flat surface H and the sub-chamfered portion 36 is greater than the
thickness D of each coating 32, 33.
[0030] As the swash plate 15 rotates, lubricant on the contact
surfaces 30, 31 of the swash plate 15 is drawn into the spaces
between the sub-chamfered portions 36 and the contact surfaces 30,
31. The lubricant is further drawn into the spaces between the main
chamfered portions 342 and the contact surfaces 30, 31 and into the
spaces between the arched surfaces 341 and the contact surfaces 30,
31.
[0031] The first embodiment provides the following advantages.
[0032] (1) The average of the first inclination angles .theta.1 of
the main chamfered portions 342 with respect to the corresponding
flat surface H is approximately 2 to 7 degrees. Each flat surface H
contacts the center P of the corresponding substantially flat
surface 34. When a foreign particle is caught between one of the
main chamfered portions 342, which has a small inclination angle
.theta.1, and the swash plate 15, the corresponding coating 32, 33
will be damaged. The maximum distance .beta. between each main
chamfered portion 342 and the corresponding contact surface 30, 31,
however, is approximately 10 .mu.m. Thus, a foreign particle that
is larger in diameter than the thickness D (approx. 70 to 90 .mu.m)
of each coating 32, 33 cannot enter the space between the main
chamfered portions 342 and the corresponding contact surface 30,
31.
[0033] In addition, foreign particles that are larger in diameter
than the thickness D of each coating 32, 33 can enter the space
between each sub-chamfered portion 36 and the corresponding contact
surface 30, 31. The average of the inclination angles .theta.2 of
the sub-chamfered portions 36 with respect to the corresponding
flat surface H, however, is approximately 40 degrees. Thus, foreign
particles do not get caught in the space between each sub-chamfered
portion 36 and the corresponding contact surfaces 30, 31. If
foreign particles that are smaller in diameter than the thickness D
of each coating 32, 33 enter the space between each main chamfered
portion 342 and the swash plate, the foreign particles are
completely buried in each coating 32, 33. Thus, the foreign
particles do not roll while being caught between each shoe and the
swash plate.
[0034] Accordingly, foreign particles larger than the thickness D,
which may easily damage each coating 32, 33, do not get caught in
the space between the swash plate 15 and the shoes 18A, 18B. This
prevents foreign particles from damaging the coatings 32, 33.
[0035] In an experiment, aluminum particles and from particles were
put in the control pressure chamber 121. The compressor was then
operated for one hour and the damage to each resin layer 322, 332
was checked. The total weight of the foreign particles was 12 mg.
The weight ratio of the aluminum particles and the iron particles
was 2:1. The maximum diameter of the foreign particles was 100
.mu.m. As a result of the experiment, no wear was found on the
resin layers 322, 332.
[0036] (2) There is lubricant on the contact surfaces 30, 31 of the
swash plate 15, on which the shoes 18A, 18B slide. The
sub-chamfered portions 36, which are inclined by the large second
inclination angle .theta.2, effectively draw the lubricant into the
space between the substantially flat surfaces 34 and the
corresponding contact surface 30, 31.
[0037] (3) The average of the second inclination angles .theta.2 of
the sub-chamfered portions 36 is approximately 40 degrees in the
first embodiment. However, if each second inclination angle
.theta.2 is more than 20 degrees, a foreign particle that is larger
in diameter then the thickness of the coating D may enter between
one of the contact surfaces 30, 31 and the corresponding
sub-chamfered portion 36. However, the foreign particle does not
get caught in the space between the sub-chamfered 36 and the
corresponding contact surface 30, 31. That is, there is little
possibility that the coatings 32, 33 will be damaged when a foreign
particle that is larger in diameter than the thickness of the
coating D enters space between one of the sub-chamfered portions 36
and the corresponding contact surface 30, 31. The second
inclination angle .theta.2 of the sub-chamfered portions 36 is more
than 20 degrees, when the second inclination angle .theta.2 of the
sub-chamfered portions 36 is more than 20 degrees and the first
inclination angle .theta.1 of the main chamfered portions 342 is
equal to or less than 20 degrees, the maximum distance .beta. of
the main chamfered portions 342 and the corresponding contact
surfaces 30, 31 must be less than the thickness D of the coating
32, 33. This prevents the foreign particles from damaging the
coatings 32, 33.
[0038] (4) When different materials slide against each other, there
is a lower liklihood of seizure, so compared with the same
materials sliding against each other The swash plate 15 is made of
iron-based material, and the metal layers 321, 331, which form
coatings 32, 33, are made of aluminum-based material. The
aluminum-based material is suitable for preventing seizure between
the swash plate 15 and the shoes 18A, 18B.
[0039] (5) It is important to apply lubricant to the space between
each contact surface 30, 31 of swash plate 15 and the center of the
corresponding substantially flat surface 34 of each shoe 18A, 18B
for extending the life time of the coatings 32, 33. Each arched
surface 341 plays an important role in drawing the lubricant into
the space between each contact surface 30, 31 of the swash plate
and the center of the corresponding substantially flat surface 34
of each shoe 18A, 18B.
[0040] (6) The sub-chamfered portion 36 eliminate sharp edges on
the shoes 18A, 18B that contact the swash plate 15.
[0041] A second embodiment will now be described with reference to
FIG. 4. Like or the same reference numerals are given to those
components that are like or the same as the corresponding
components of the first embodiment.
[0042] An arched surface 341 and a main chamfered portion 342C of
each shoe 18C are smoothly joined to each other. The main chamfered
portion 342C and a sub-chamfered portion 36D are smoothly joined to
each other. The average of first inclination angles .theta.1 of the
main chamfered portions 342C of the shoes 18C with respect to a
corresponding flat surface H is approximately 10 degrees. The
average of second inclination angles .theta.2 of the sub-chamfered
portions 36C with respect to the corresponding flat surface H is
the same as that of the first embodiment. The maximum distance
.beta. between each main chamfered portion 342C and the
corresponding flat surface H is approximately 70 to 80 .mu.m. The
thickness D of the coatings 32, 33 is the same as in the first
embodiment.
[0043] The second embodiment provides the same advantages as in the
first embodiment.
[0044] A third embodiment is shown in FIG. 5. Like or the same
reference numerals are given to those components that are like or
the same as the corresponding components of the first
embodiment.
[0045] An arched surface 341 and a main chamfered portion 342D of
each shoe 18D are smoothly joined to each other, The main chamfered
portion 342D and a sub chamfered portion 36D are smoothly joined to
each other. The average of first inclination angles .theta.1 of the
main chamfered portions 342D of the shoes 18D with respect to a
corresponding flat surface H is approximately 10 degrees. Tho
average of second inclination angles .theta.2 of the sub-chamfered
portions 36D with respect to the corresponding flat surface H is
approximately 60 degrees. The maximum distance .beta. between each
main chamfered portion 342D and the corresponding flat surface H is
approximately 70 to 80 .mu.m. The thickness D of the coatings 32,
33 is the same as in the first embodiment.
[0046] The third embodiment also provides the same advantages as in
the first embodiment.
[0047] A fourth embodiment is shown in FIG. 6. Like or the same
reference numerals are given to those components that are like or
the same as the corresponding components of the first
embodiment.
[0048] An arched surface 341 and a main chamfered portion 342E of
each shoe 18E are smoothly joined to each other. The main chamfered
portion 342E and a sub-chamfered portion 36E are smoothly joined to
each other. The main chamfered portion 342E is formed of an
outwardly arched chamfered portion 342E1 and a surrounding,
inwardly arched chamfered portion 342E2. The chamfered portions
342E1 and 342E2 are smoothly joined to each other. The average of
first inclination angles .theta.1 of the main chamfered portions
342E of the shoes 18E with respect to a corresponding flat surface
H is approximately 10 degrees. The average of second inclination
angles .theta.2 of the sub-chamfered portions 36E with respect to
the corresponding flat surface H is approximately 40 degrees. The
maximum distance .beta. between each main chamfered portion 342E
and the corresponding flat surface H is approximately 70 to 80
.mu.m. The thickness D of the coatings 32, 33 is the same as in the
first embodiment.
[0049] The fourth embodiment provides the same advantages as the
first embodiment. The present invention includes further
embodiments as follows.
[0050] (1) The present intention may be used in a compressor that
has a swash plate that is coated only by resin that contains solid
lubricant.
[0051] (2) The present invention may be used in a compressor that
has a swash plate that is coated only by metal.
[0052] (3) In the second, third, and fourth embodiments, the
sub-chamfered portion may be eliminated and the main chamfered
portion may be connected to the semi-spherical portion of each shoe
directly.
[0053] It should be apparent to those skilled in the art that the
present invention may be embodied in many other specific forms
without departing from the spirit or scope of the invention.
Particularly, it should be understood that the invention may be
embodied in the following forms.
[0054] Therefore, the present examples and embodiments are to be
considered as illustrative and not restrictive and the invention is
not to be limited to the details given herein, but may be modified
within the scope and equivalence of the appended claims.
* * * * *