U.S. patent application number 14/230113 was filed with the patent office on 2014-10-09 for compressor.
This patent application is currently assigned to Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.). The applicant listed for this patent is Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.). Invention is credited to Kenji Nagura, Takashi OKUNO.
Application Number | 20140301872 14/230113 |
Document ID | / |
Family ID | 50241273 |
Filed Date | 2014-10-09 |
United States Patent
Application |
20140301872 |
Kind Code |
A1 |
OKUNO; Takashi ; et
al. |
October 9, 2014 |
COMPRESSOR
Abstract
A compressor of the present invention includes a crank shaft, a
bearing, a casing, an outer-race gear that is disposed so as to
surround the crank shaft, a planetary gear that has a radius of a
pitch circle set to a half of a radius of a pitch circle of the
outer-race gear and causes the crank shaft to be inserted
therethrough so that the planetary gear rotates relative to the
crank shaft, a piston that is connected to the planetary gear so as
to rotate relative to the planetary gear and moves in a
reciprocating manner in the direction parallel to the radial
direction of the outer-race gear inside the casing in a manner such
that the planetary gear rotates inside the outer-race gear while
engaging with the outer-race gear, and a pump that supplies
lubricant to the bearing. Here, the pump is accommodated inside the
casing.
Inventors: |
OKUNO; Takashi;
(Takasago-shi, JP) ; Nagura; Kenji; (Takasago-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) |
Kobe-shi |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Kobe Seiko Sho
(Kobe Steel, Ltd.)
Kobe-shi
JP
|
Family ID: |
50241273 |
Appl. No.: |
14/230113 |
Filed: |
March 31, 2014 |
Current U.S.
Class: |
417/364 |
Current CPC
Class: |
F04B 49/126 20130101;
F04B 9/045 20130101; F04B 27/073 20130101; F04B 39/0246 20130101;
F04B 39/0261 20130101; F04B 39/0207 20130101; F04B 49/125 20130101;
F04B 27/0414 20130101; F04B 35/002 20130101 |
Class at
Publication: |
417/364 |
International
Class: |
F04B 35/00 20060101
F04B035/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 8, 2013 |
JP |
2013-080539 |
Claims
1. A compressor comprising: a crank shaft that is rotationally
driven by a prime mover; a bearing that receives the crank shaft; a
casing that accommodates the crank shaft and the bearing; an
outer-race gear that is disposed inside the casing so as to
surround the crank shaft; a planetary gear that has a radius of a
pitch circle set to a half of a radius of a pitch circle of the
outer-race gear and causes the crank shaft to be inserted
therethrough so that the planetary gear rotates relative to the
crank shaft; a piston that is connected to the planetary gear so as
to rotate relative to the planetary gear, the piston moving in a
reciprocating manner along the direction parallel to the radial
direction of the outer-race gear inside the casing when the
planetary gear rotates inside the outer-race gear while engaging
with the outer-race gear; and a pump that is accommodated inside
the casing and supplies lubricant to the bearing.
2. The compressor according to claim 1, wherein the crank shaft is
connected to the pump so that the pump is driven by the rotation of
the crank shaft.
3. The compressor according to claim 1, wherein an oil buffer is
formed between the crank shaft and an attachment wall for the pump.
Description
BACKGROUND OF THE INVENTION
[0001] 1. (Field of the Invention)
[0002] The present invention relates to a compressor.
[0003] 2. (Description of the Related Art)
[0004] Hitherto, there is known a compressor that includes a
so-called hypocycloid mechanism with an outer-race gear and a
planetary gear. For example, JP 60-144594 A discloses a compressor
including a crank shaft that is rotationally driven by a motor, a
casing that accommodates the crank shaft, an outer-race gear that
is disposed so as to surround the crank shaft, a planetary gear
that rotates inside the outer-race gear while engaging with an
inner gear of the outer-race gear, and a piston that is connected
to the planetary gear so as to rotate relative to the planetary
gear. The planetary gear causes the crank shaft to be inserted
therethrough so that the planetary gear rotates relative to the
crank shaft. Further, a radius of a pitch circle of the planetary
gear is set to a half of a radius of a pitch circle of the
outer-race gear. The casing includes a cylinder that has a shape
extending linearly along the direction parallel to the radial
direction of the outer-race gear, and the piston is accommodated
inside the cylinder. Further, an engagement point between the
outer-race gear and the planetary gear while the piston is located
at the top dead center inside the cylinder is set so as to match a
point close to the piston in the intersection point between the
pitch circle of the outer-race gear and the longitudinal direction
of the cylinder. For this reason, when the planetary gear rotates
inside the outer-race gear (revolves about the center of the
outer-race gear) while engaging with the outer-race gear with the
rotation of the crank shaft, the piston linearly moves in a
reciprocating manner along the longitudinal direction of the
cylinder inside the cylinder. Here, the cylinder has a shape in
which the piston is guided in the longitudinal direction thereof
while taking the posture of the piston at the top dead center, that
is, a shape in which the piston is guided so as to move in a
reciprocating manner along the longitudinal direction thereof
without causing the piston to be inclined with respect to the
longitudinal direction of the cylinder. Accordingly, when the
planetary gear revolves inside the outer-race gear in a spinning
state, the piston moves in a reciprocating manner while taking the
same posture inside the cylinder. That is, in the compressor, the
rotational movement of the planetary gear that is driven so as to
revolve inside the outer-race gear by the crank shaft is converted
into the linear reciprocating movement of the piston.
SUMMARY OF THE INVENTION
[0005] In general, the compressor of the related art includes a
bearing that receives the crank shaft, and lubricant is supplied
into the bearing by a pump. Then, there is a case in which the
lubricant leaks from the pump when the lubricant is supplied from
the pump to the bearing. In this case, since there is a need to
provide an oil receiving portion that receives the lubricant
leaking from the pump, cost increases and the number of components
increases. In order to remove the oil receiving portion, there is a
need to use a high-performance pump having excellent lubricant
sealing performance. Even in this case, there is an increase in
cost.
[0006] An object of the present invention is to provide a
compressor that includes a hypocycloid mechanism and may decrease
the number of components at low cost.
[0007] In order to solve the above-described problems, a compressor
according to the present invention includes: a crank shaft that is
rotationally driven by a prime mover; a bearing that receives the
crank shaft; a casing that accommodates the crank shaft and the
bearing; an outer-race gear that is disposed inside the casing so
as to surround the crank shaft; a planetary gear that has a radius
of a pitch circle set to a half of a radius of a pitch circle of
the outer-race gear and causes the crank shaft to be inserted
therethrough so that the planetary gear rotates relative to the
crank shaft; a piston that is connected to the planetary gear so as
to rotate relative to the planetary gear and moves in a
reciprocating manner along the direction parallel to the radial
direction of the outer-race gear inside the casing when the
planetary gear rotates inside the outer-race gear while engaging
with the outer-race gear; and a pump that is accommodated inside
the casing and supplies lubricant to the bearing.
[0008] According to the present invention, the pump is accommodated
inside the casing. For this reason, even when the lubricant leaks
from the pump when the lubricant is supplied to the bearing, the
lubricant stays inside the casing, and does not leak to the outside
of the casing. Accordingly, there is no need to additionally
provide a component such as an oil receiving portion that receives
the lubricant leaking from the pump, and the leakage of the
lubricant from the pump is permitted. Thus, there is no need to use
a high-performance pump having excellent lubricant sealing
performance. Further, since the compressor of this embodiment
includes a so-called hypocycloid mechanism with the outer-race gear
and the planetary gear, there is no need to require a strict
lubricating condition like a compressor using a piston crank
mechanism with a cross head. In addition, since the rotational
movement of the crank shaft is directly converted into the
reciprocating movement of the piston, the power transmission
efficiency is excellent compared to the compressor using the piston
crank mechanism.
[0009] Even in this case, the crank shaft may be connected to the
pump so that the pump is driven by the rotation of the crank
shaft.
[0010] With such a configuration, since the prime mover as the
power source for rotating the crank shaft is used as the power
source of the pump, there is no need to provide a dedicated power
source for driving the pump, and hence the structure becomes
simplified.
[0011] Further, in the present invention, an oil buffer may be
formed between the crank shaft and an attachment wall for the
pump.
[0012] With such a configuration, the lubricant may be sufficiently
supplied to the bearing and the like.
[0013] As described above, according to the present invention, it
is possible to provide a compressor that includes a hypocycloid
mechanism and may decrease the number of components at low
cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a cross-sectional view schematically illustrating
the structure of a compressor of a first embodiment of the present
invention.
[0015] FIG. 2 is a cross-sectional view taken along the line II-II
of FIG. 1.
[0016] FIG. 3 is a cross-sectional view illustrating the compressor
of FIG. 1 when viewed from a different angle.
[0017] FIG. 4 is a cross-sectional view illustrating the vicinity
of an attachment wall for a compressor of a second embodiment of
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0018] A compressor of a first embodiment of the present invention
will be described by referring to FIGS. 1 to 3.
[0019] As illustrated in FIGS. 1 to 3, a compressor of this
embodiment includes a crank shaft 10 that is rotationally driven by
a prime mover, a bearing 12 that receives the crank shaft 10, a
casing 20, an outer-race gear 30 that is disposed inside the casing
20, a planetary member (planetary carrier) 40 that includes a
planetary gear 42 engaging with an inner gear 32 of the outer-race
gear 30, a piston 50 that moves in a reciprocating manner along a
specific reciprocating direction inside the casing 20 while
rotating relative to the planetary member 40, and a pump 60 that
supplies lubricant to the bearing 12 or each gear. Furthermore,
FIG. 2 is a cross-sectional view taken along the line II-II of FIG.
1, but FIG. 2 illustrates an imaginary planetary gear 42. Further,
FIG. 2 illustrates a pitch circle P of the planetary gear 42 by the
one-dotted chain line.
[0020] As illustrated in FIGS. 1 and 3, the crank shaft 10 includes
a main shaft 10a that is connected to the prime mover, a crank pin
10b that includes a center axis O2 disposed at a position biased
from the center axis O1 of the main shaft 10a so as to extend in a
direction parallel to the center axis O1, and a crank arm 10c that
connects the main shaft 10a to the crank pin 10b.
[0021] As illustrated in FIGS. 1 and 2, the casing 20 mainly
includes a crank casing 21 that accommodates the crank shaft 10 and
a cylinder 28 that accommodates the piston 50. Furthermore, a
suction line that suctions a gas such as a hydrogen gas into the
cylinder 28 and a discharge line that discharges a gas compressed
inside the cylinder 28 to the outside of the cylinder 28 are not
illustrated in the drawings.
[0022] The crank casing 21 accommodates the crank shaft 10, the
bearing 12, the outer-race gear 30, the planetary member 40, a part
of the piston 50, and the pump 60. More specifically, the crank
casing 21 includes a main body 22 that accommodates the crank shaft
10, the bearing 12, the outer-race gear 30, the planetary member
40, and a part of the piston 50 and a pump accommodation portion 25
that accommodates the pump 60. As illustrated in FIGS. 1 and 3, the
pump accommodation portion 25 is adjacent to the main body 22 in
the direction of the center axis O1 of the main shaft 10a. An
attachment wall 26 for the pump 60 is provided in the boundary
between the main body 22 and the pump accommodation portion 25
inside the crank casing 21. An oil buffer 27 that retains lubricant
drawn from the pump 60 is formed in a space surrounded by the
attachment wall 26, the main body 22, and the crank shaft 10. In
this embodiment, the crank casing 21 has airtightness and pressure
resistance. More specifically, the pressure resistance corresponds
to the pressure resistance capable of withstanding the pressure
substantially equal to the pressure of the gas suctioned from the
suction line.
[0023] As illustrated in FIGS. 1 and 3, the main body 22 includes a
first wall 23 that holds the crank arm 10c close to the main shaft
10a and a second wall 24 that holds the crank arm 10c distant from
the main shaft 10a. The first wall 23 includes a first opening that
is formed in the direction of the center axis O1, and the first
opening retains the main shaft 10a and retains the crank arm 10c
and the bearing 12 on the close side from the main shaft 10a. The
second wall 24 includes a second opening that is formed in the
direction of the center axis O1, and the second opening retains the
bearing 12 and the crank arm 10c on the far side from the main
shaft 10a. The first wall 23 and the second wall 24 are disposed so
as to face each other in a posture in which both walls are
perpendicular to the center axis O1. The attachment wall 26 is
attached to the outer surface of the second wall 24 so as to block
the second opening of the second wall 24. As illustrated in FIG. 3,
a lower end 24a of the second wall 24 is separated from the bottom
wall of the crank casing 21, and hence the inside of the main body
22 is connected to the inside of the pump accommodation portion 25.
For this reason, the lubricant that is supplied to each bearing or
each gear and falls to the lower portion of the main body 22 is led
to the pump accommodation portion 25. That is, the lower portion of
the main body 22 and the lower portion of the pump accommodation
portion 25 serve as an oil reservoir. The pump accommodation
portion 25 has a shape that surrounds the pump 60 along with the
attachment wall 26. Furthermore, the inner surface of the bottom
wall of the pump accommodation portion 25 is set to a position
lower than the inner surface of the bottom wall of the main body
22.
[0024] As illustrated in FIG. 1, the cylinder 28 extends in a
linear shape along the direction parallel to the radial direction
of the circle formed about the center axis O1 of the outer-race
gear 30 within a horizontal plane. The cylinder 28 guides the
reciprocating movement of the piston 50 along the parallel
direction (the reciprocating direction).
[0025] As illustrated in FIGS. 1 and 3, the bearing 12 is provided
between the crank shaft 10 and the crank casing 21, and more
specifically, between the crank arm 10c and the main body 22.
Further, a first bearing 14 that permits the rotation of the
planetary member 40 relative to the crank pin 10b is provided
between the crank shaft 10 and the planetary member 40, and a
second bearing 16 that permits the rotation of the piston 50
relative to the planetary member 40 is provided between the
planetary member 40 and the piston 50.
[0026] The outer-race gear 30 is an internally-toothed gear that
includes the inner gear 32. As illustrated in FIG. 3, the
outer-race gear 30 has a radius larger than the rotation radius of
the crank pin 10b, and is disposed inside the main body 22 of the
crank casing 21 so as to surround the crank shaft 10. More
specifically, the outer-race gear 30 is attached to the inner
surface of the second wall 24 of the main body 22 in a posture in
which the center thereof matches the center axis O1 of the main
shaft 10a of the crank shaft 10.
[0027] The planetary member 40 includes the planetary gear 42 that
engages with the outer-race gear 30, an eccentric shaft 44 that is
connected to the planetary gear 42, and a counter weight 46 that is
connected to the eccentric shaft 44. As illustrated in FIGS. 1 and
3, the planetary gear 42, the eccentric shaft 44, and the counter
weight 46 are connected in this order in the direction of the
center axis O1 of the main shaft 10a so as to rotate together. The
crank pin 10b of the crank shaft 10 is inserted through the
planetary member 40 so that the planetary member 40 rotates
relative to the crank shaft 10.
[0028] The planetary gear 42 rotates inside the outer-race gear 30
(revolves about the center axis O1) while engaging with the
outer-race gear 30 as the crank pin 10b of the crank shaft 10
rotates about the center axis O1. The radius of the pitch circle P
(see FIG. 2) of the planetary gear 42 is set to a half of the
radius of the pitch circle of the outer-race gear 30. Here, an
engagement point (hereinafter, referred to as a "top dead center
engagement point P1") between the outer-race gear 30 and the
planetary gear 42 while the piston 50 is located at the top dead
center inside the cylinder 28 is set so as to match the point close
to the piston 50 in the intersection point between the pitch circle
of the outer-race gear 30 and the longitudinal direction of the
cylinder 28. Then, since the radius of the pitch circle P of the
planetary gear 42 is a half of the radius of the outer-race gear
30, the top dead center engagement point P1 linearly moves in a
reciprocating manner along the longitudinal direction of the
cylinder 28, that is, the reciprocating direction with the rotation
of the planetary gear 42.
[0029] As illustrated in FIGS. 1 and 3, the eccentric shaft 44 is
adjacently connected to the planetary gear 42 in the direction of
the center axis O1 so that the center thereof is located at a
position biased from the center axis of the planetary gear 42 (the
center axis O2 of the crank pin 10b). Specifically, the center axis
of the eccentric shaft 44 is set so as to pass the top dead center
engagement point P1. For this reason, the eccentric shaft 44
rotates (spins) about the center axis of the eccentric shaft 44
while rotating relative to the crank pin 10b with the revolution of
the planetary gear 42, and linearly moves in a reciprocating manner
along the reciprocating direction. In this embodiment, the
eccentric shaft 44 is formed in a disk shape.
[0030] As illustrated in FIGS. 1 and 2, the counter weight 46 is
adjacently connected to the eccentric shaft 44 in the direction of
the center axis O1 so that the center of gravity thereof is located
at the opposite to the center of gravity of the eccentric shaft 44
with respect to the center axis of the planetary gear 42.
[0031] As illustrated in FIGS. 1 and 2, the piston 50 includes an
annular portion 52 that surrounds the eccentric shaft 44 through
the second bearing 16, a piston rod 54 that extends in the
longitudinal direction of the cylinder 28 from the annular portion
52, and a piston body 56 that is connected to the front end of the
piston rod 54.
[0032] The annular portion 52 is rotatable relative to the
eccentric shaft 44. For this reason, the annular portion 52
linearly moves in the reciprocating direction so as to follow the
linear movement of the eccentric shaft 44 along the reciprocating
direction. That is, since the second bearing 16 is interposed
between the eccentric shaft 44 and the annular portion 52, the
rotational movement of the eccentric shaft 44 is not transmitted to
the annular portion 52, and only the linear movement of the
eccentric shaft 44 is transmitted to the annular portion 52.
[0033] The piston rod 54 has a shape that extends along the
extension line of the track of the center of the eccentric shaft 44
during the reciprocating movement of the eccentric shaft 44 (the
track of the top dead center engagement point P1 during the
revolution of the planetary gear 42 about the center axis O1) along
the reciprocating direction. The piston rod 54 linearly moves
inside the cylinder 28 along with the linear movement of the
annular portion 52 in the reciprocating direction.
[0034] Here, the cylinder 28 has a shape in which the piston 50 is
guided in the longitudinal direction while the posture of the
piston 50 at the top dead center is maintained. More specifically,
the cylinder 28 has a shape in which the piston body 56 is guided
in a reciprocating manner along the longitudinal direction thereof
without being inclined with respect to the longitudinal direction
of the cylinder 28. For this reason, when the planetary gear 42
revolves about the center axis O1 in a spinning state, the piston
body 56 linearly moves in a reciprocating manner inside the
cylinder 28 while taking the same posture as that of the top dead
center. Thus, the piston body 56 compresses a gas suctioned from
the suction line.
[0035] As illustrated in FIGS. 1 and 3, the pump 60 includes a pump
body 62 that supplies lubricant to each of the bearings (the
bearing 12, the first bearing 14, and the second bearing 16) and
the gears, and a suction portion 66 that suctions the lubricant
from the oil reservoir inside the crank casing 21 to the pump body
62. The pump body 62 is attached to the attachment wall 26 provided
inside the crank casing 21. The pump body 62 is connected to the
crank shaft 10 through a coupling 64 disposed in a hole formed in
the attachment wall 26. Specifically, the coupling 64 connects a
portion passing the center axis O1 in the crank arm 10c distant
from the main shaft 10a to a rotor (not illustrated) built in the
pump body 62. For this reason, the drive power of the crank shaft
10 is transmitted to the pump body 62 through the coupling 64. The
pump body 62 supplies the lubricant suctioned from the oil
reservoir inside the crank casing 21 by the suction portion 66 to
each bearing or each gear at a predetermined supply pressure
through a supply line 68 (see FIG. 1).
[0036] Here, the pressure inside the crank casing 21 becomes a
pressure substantially equal to the pressure of the gas suctioned
from the suction line, and the supply pressure at which the pump 60
supplies the lubricant becomes a pressure (hereinafter, referred to
as a "pure supply pressure") purely necessary for supplying the
lubricant to each bearing or each gear. For this reason, the
sealing pressure that seals the leakage of the lubricant from the
inside of the pump body 62 to the outside of the pump body 62 may
be set to the pure supply pressure or so. On the contrary, in a
case where the crank casing 21 has airtightness and pressure
resistance and the pump 60 is disposed at the outside of the casing
20, the supply pressure at which the pump 60 supplies the lubricant
becomes the sum of the inner pressure of the crank casing 21 and
the pressure at which the lubricant is supplied to each bearing or
each gear. For this reason, the sealing pressure that seals the
leakage of the lubricant from the inside of the pump body 62 to the
outside of the pump body 62 becomes higher than the pure supply
pressure. That is, in this embodiment, since the crank casing 21
has airtightness and pressure resistance and the pump 60 is
accommodated inside the casing 20, the sealing pressure of the pump
60 may be decreased. Thus, it is possible to ensure the sealing
performance of the pump without using a high-performance pump
having excellent sealing performance.
[0037] Next, the running operation of the compressor of this
embodiment will be described.
[0038] When the prime mover is driven, the crank shaft 10 is
rotationally driven. In accordance with this rotational driving
operation, the planetary gear 42 spins about the center axis O2 of
the crank pin 10b while rotating relative to the crank pin 10b of
the crank shaft 10 and revolves about the center axis 01 of the
main shaft 10a inside the outer-race gear 30 while engaging with
the outer-race gear 30. Here, the top dead center engagement point
P1 is set so as to match the point near the piston 50 in the
intersection point between the pitch circle of the outer-race gear
30 and the longitudinal direction of the cylinder 28. Furthermore,
since the radius of the pitch circle P of the planetary gear 42 is
a half of the radius of the outer-race gear 30, the eccentric shaft
44 linearly moves in a reciprocating manner along the reciprocating
direction along with the planetary gear 42 while rotating
(spinning) about the center axis thereof, when the planetary gear
42 revolves inside the outer-race gear 30 while the engagement
point of both gears is maintained at the top dead center engagement
point P1. The piston 50 linearly moves in a reciprocating manner in
the reciprocating direction relative to the eccentric shaft 44 so
as to follow the reciprocating movement of the eccentric shaft 44.
Thus, a gas suctioned from the suction line is compressed. Further,
the pump 60 occasionally supplies the lubricant suctioned from the
oil reservoir inside the crank casing 21 to each bearing or each
gear.
[0039] As described above, in the compressor of this embodiment,
the pump 60 is accommodated inside the casing 20. For this reason,
even when the lubricant leaks from the pump 60 when the lubricant
is supplied to the bearing 12 or each gear, the lubricant stays
inside the casing 20 and does not leak to the outside of the casing
20. Accordingly, there is no need to additionally provide a
component such as an oil receiving portion that receives the
lubricant leaking from the pump 60, and the leakage of the
lubricant from the pump 60 is permitted. Thus, there is no need to
use a high-performance pump having excellent lubricant sealing
performance. Further, since the compressor of this embodiment
includes a so-called hypocycloid mechanism with the outer-race gear
30 and the planetary gear 42, there is no need to require a strict
lubricating condition like a compressor using a piston crank
mechanism with a cross head. In addition, the rotational movement
of the crank shaft 10 is directly converted into the reciprocating
movement of the piston 50. Therefore, the power transmission
efficiency is excellent compared to the compressor using the piston
crank mechanism.
[0040] Further, in this embodiment, since the crank shaft 10 is
connected to the pump 60 so that the pump 60 is driven by the
rotation of the crank shaft 10, the prime mover as the power source
for rotating the crank shaft 10 is used as the power source of the
pump 60. Accordingly, since there is no need to provide a dedicated
power source for driving the pump 60, the structure becomes
simplified.
[0041] Further, in this embodiment, since the oil buffer 27 is
formed in a space surrounded by the attachment wall 26, the main
body 22, and the crank shaft 10, the lubricant may be sufficiently
supplied to the bearing 12 and the like.
[0042] Further, in the compressor of this embodiment, the crank
casing 21 has airtightness and pressure resistance in addition to
the configuration in which the pump 60 is accommodated inside the
crank casing 21. Accordingly, the sealing pressure for sealing the
leakage of the lubricant from the inside of the pump 60 to the
outside of the pump 60 may be decreased so as to become the pure
supply pressure or so. Thus, it is possible to ensure the sealing
performance of the pump without using a high-performance pump
having excellent sealing performance.
Second Embodiment
[0043] FIG. 4 is a cross-sectional view illustrating the vicinity
of the attachment wall 26 of a compressor of a second embodiment of
the present invention. Furthermore, in the second embodiment, only
the difference from the first embodiment will be described, and the
structure, the operation, and the effect which are the same as
those of the first embodiment will not be described.
[0044] In this embodiment, a cylindrical member 29 is attached to
the surface opposite to the attachment surface for the pump 60 in
the attachment wall 26. The end of the crank shaft 10 is inserted
into the cylindrical member 29. An oil seal 29a is attached between
the cylindrical member 29 and the end of the crank shaft 10. Thus,
a space is formed which is surrounded by the cylindrical member 29,
the crank shaft 10, and the attachment wall 26. That is, in this
embodiment, this space serves as the oil buffer 27. For this
reason, in this embodiment, the volume capacity of the oil buffer
27 may be flexibly adjusted through the adjustment of the inner
diameter of the cylindrical member 29. Furthermore, the cylindrical
member 29 may be formed as a single member with the attachment wall
26.
[0045] Furthermore, it is understood that the embodiments disclosed
herein are merely examples and do not limit the present invention
in all respects. The scope of the present invention is expressed by
claims instead of the embodiments, and includes the meaning
equivalent to claims and all modifications within the scope.
[0046] For example, in the above-described embodiment, an example
has been described in which the crank shaft 10 and the pump body 62
are connected to each other through the coupling 64. However, the
pump 60 may be driven while being independent from the crank shaft
10. That is, a power source that drives the pump 60 may be provided
separately from the prime mover that rotates the crank shaft 10.
With such a configuration, it is possible to individually manage
the driving of the crank shaft 10 and the driving of the pump
60.
[0047] Further, a portion that holds the bearing 12 may be a member
separated from the first wall 23 or the second wall 24. The piston
50 may be driven in an arbitrary direction such as a gravity
direction, so long as the piston moves in a reciprocating manner
along the direction parallel to the radial direction of the
outer-race gear 30.
* * * * *