U.S. patent application number 09/961910 was filed with the patent office on 2002-04-04 for scroll compressor having an electric motor incorporated.
This patent application is currently assigned to Kabushiki Kaisha Toyota Jidoshokki. Invention is credited to Fujii, Toshiro, Moroi, Takahiro.
Application Number | 20020039534 09/961910 |
Document ID | / |
Family ID | 18781544 |
Filed Date | 2002-04-04 |
United States Patent
Application |
20020039534 |
Kind Code |
A1 |
Moroi, Takahiro ; et
al. |
April 4, 2002 |
Scroll compressor having an electric motor incorporated
Abstract
In a scroll compressor with an electric motor incorporated of
the present invention, a housing is provided with a cooling chamber
which is provided adjacently on the outer peripheral side of a
motor portion, so that cooling fluid is supplied to the cooling
chamber, and a high pressure chamber which is provided adjacently
on the outer peripheral side of the cooling chamber so that a gas,
compressed by a fixed scroll and a movable scroll, is supplied to
the high pressure chamber. Consequently, reduction in the mass flow
rate of the discharge gas of the compressor can be suppressed, and
it is possible to cool both the discharge gas and the motor portion
by the single cooling chamber.
Inventors: |
Moroi, Takahiro;
(Kariya-shi, JP) ; Fujii, Toshiro; (Kariya-shi,
JP) |
Correspondence
Address: |
Woodcock Washburn Kurtz Mackiewics & Norris LLP
46th Floor
One Liberty Place
Philadelphia
PA
19103
US
|
Assignee: |
Kabushiki Kaisha Toyota
Jidoshokki
|
Family ID: |
18781544 |
Appl. No.: |
09/961910 |
Filed: |
September 24, 2001 |
Current U.S.
Class: |
417/372 ;
417/410.5 |
Current CPC
Class: |
F04C 29/045 20130101;
F04C 18/0215 20130101; F04C 23/008 20130101; F04C 29/04
20130101 |
Class at
Publication: |
417/372 ;
417/410.5 |
International
Class: |
F04B 035/04; F04B
039/06; F04B 039/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2000 |
JP |
2000-299781 |
Claims
What is claimed is:
1. A scroll compressor, with an electric motor incorporated,
comprising: a housing accommodating a compressor portion and a
motor portion, the motor portion driving a movable scroll, and the
compressor portion having a fixed scroll secured to the housing and
the movable scroll which is located eccentrically with respect to
the fixed scroll so as to orbit with respect to the fixed scroll, a
cooling chamber which is provided adjacently on the outer
peripheral side of the motor portion, and a high pressure chamber
which is provided adjacently on the outer peripheral side of the
cooling chamber, so that gas compressed by the fixed scroll and the
movable scroll is supplied to the high pressure chamber, wherein a
cooling fluid is supplied to the cooling chamber to cool both the
gas and the motor portion.
2. A scroll compressor according to claim 1, wherein said high
pressure chamber and a discharge port of said housing is connected
by a gas passage for highly pressurized gas formed at the outside
of said housing.
3. A scroll compressor according to claim 1, wherein said cooling
chamber and said high pressure chamber are formed annularly around
said motor portion.
4. A scroll compressor according to claim 1, wherein said cooling
fluid is water.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a scroll compressor and,
more specifically, it relates to a scroll compressor having an
electric motor incorporated for compressing a gas to be supplied to
a fuel cell.
[0003] 2. Description of the Related Art
[0004] In recent years, the automobile industry has increasingly
been placing emphasis on electric motor cars in the hope of
reducing the consumption of petroleum resources. A fuel cell, as a
drive source for an electric motor car, exhibits high energy
conversion efficiency and is environmentally friendly because only
nontoxic reaction products, such as water or carbon dioxide, are
produced and, hence, it is expected that the demand for fuel cell
system will increase. A scroll compressor which can be made small
and light is suitable as a compressor to compress gases to be
supplied to the fuel cell.
[0005] It is preferable that the rise in temperature of the air is
restricted so that the work load of the scroll compressor is small.
To this end, as in a scroll compressor disclosed in Japanese
Unexamined Patent Publication (Kokai) No. 8-247056, a cooling
chamber is provided around a high-pressure chamber to circulate
cooling water, to thereby restrict a rise in temperature of the
highly pressurized air.
[0006] FIG. 2 shows an axial sectional view of a known scroll
compressor. In the known scroll compressor, a housing 1 is
comprised of a front casing 2, a rear casing 3 and an end plate 20.
The front casing 2 has a small diameter portion at a front side
thereof, having a recess at a front end surface of the small
diameter portion, and a large diameter portion at a rear side
thereof. The end plate 20 is provided at the front side of the
front casing 2, and the rear casing 3 is provided at the rear side
of the front casing 2.
[0007] A fixed scroll 21 which extends in the axial direction is
provided at a boundary surface 2a in the front casing 2. A suction
portion 22 is formed on the outer peripheral portion of the fixed
scroll 21, and a discharge portion 25 is formed on the inner
peripheral portion of the fixed scroll 21. A discharge valve 24 and
a high pressure chamber 25 are formed in front of the discharge
portion 23. A crank-shaped drive shaft 30 is rotatably supported at
its one end (rear end) of the rear casing 3. An end plate 32, which
is provided with an axially extending movable scroll 31, is
rotatably connected to the other end of the drive shaft 30.
[0008] When the drive shaft 30 rotates to make orbital movement of
the movable scroll 31, the space defined between the fixed scroll
21 and the movable scroll 31 is reduced in volume and hence the air
in the space is gradually compressed and is moved toward the
discharge portion 23. The air reaching the discharge portion 23 is
discharged to the outside of the compressor from a discharge port
20a through the discharge valve 24 and the high pressure chamber
25.
[0009] The cooling water is introduced into a cooling chamber 26
through an inlet port not shown. The cooling chamber 26 is located
adjacent the high pressure chamber 25. Consequently, the
temperature of the cooling water is increased due to heat
transferred from the highly pressurized air in the high pressure
chamber 25. The cooling water whose temperature has been increased
is discharged to the outside of the compressor from an outlet port
not shown. In a known scroll compressor, the discharged gas, i.e.,
the highly pressurized air is cooled in the way mentioned
above.
[0010] It is necessary to provide an electric motor or the like as
a drive means in the scroll compressor. In a scroll compressor with
a motor integrally incorporated therein, the compressor system
including the motor can be entirely made small. Therefore, the
scroll compressor with an electric motor incorporated is
particularly advantageously used as a compressor for supplying a
gas to a fuel cell which is in a remarkably restricted
accommodation space. In a scroll compressor with an electric motor
incorporated, it is necessary to remove heat generated from a rotor
or the like which rotates at high speed, in the motor. To this end,
a cooler such as a fan is provided in the motor, in addition to the
cooling chamber for cooling the highly pressurized air.
[0011] The gas to be supplied to the fuel cell, i.e., the discharge
gas of the compressor must be humidified to some extent. To this
end, a vapor exchange diaphragm is provided in the vicinity of the
discharge port of the compressor to humidify the discharged gas.
The heat-resistance critical temperature of the vapor exchange
diaphragm is approximately 140.degree. C. Therefore, the
temperature of the discharge gas must be cooled to below the
critical temperature. From only the viewpoint of cooling of the
discharge gas, a conventional compressor having a cooling chamber
could be used for the fuel cell.
[0012] However, if the conventional scroll compressor with an
electric motor incorporated is used for the fuel cell, the
following problems are raised. For the gas to be supplied to the
fuel cell, i.e., the discharge gas of the compressor, it is
preferable that the mass flow rate is increased because the mass of
the gas to be supplied to the fuel cell is increased. However, the
cooling chamber of the conventional scroll compressor is formed in
front of the end face of the front casing and, hence, the gas
introduced into the compressor from the outer peripheral side of
the end face can be heated by the cooling water which has been
subjected to heat exchange.
[0013] If the suction gas is heated and consequently its volume is
increased, the density is reduced but the volume flow rate is
constant. Consequently, the mass flow rate of the suction gas is
reduced and, accordingly, the mass flow rate of the discharge gas
is reduced. Namely, in the conventional compressor in which the
cooling chamber is formed at the end face, the mass of the gas to
be supplied to the fuel cell is reduced.
[0014] Moreover, as mentioned above, in the conventional scroll
compressor with an electric motor incorporated, the cooling means
for the motor portion and the cooling means (cooling chamber) for
the highly pressurized air are separately provided.
[0015] The inventor of the present invention has discovered that if
a high pressure chamber to which the discharge gas after
compression is supplied, is provided on the motor side of the
housing, and only one cooling chamber as a cooling means is
provided adjacent both the high pressure chamber and a motor
portion, not only can reduction in the mass flow rate of the
discharge gas be suppressed but also the discharge gas and the
motor portion can be cooled by the single cooling means.
SUMMARY OF THE INVENTION
[0016] A scroll compressor with an electric motor incorporated of
the present invention has been completed, based on the
above-mentioned discovery. It is an object of the present invention
to prevent the mass flow rate of the discharge gas from being
reduced and to make it possible to cool both the discharge gas and
the motor portion by a single cooling chamber.
[0017] A scroll compressor with an electric motor incorporated,
according to the present invention, comprises a housing
accommodating a compressor portion and a motor portion, the motor
portion driving a movable scroll, and the compressor portion having
a fixed scroll secured to the housing and the movable scroll which
is located eccentrically with respect to the fixed scroll so as to
orbit with respect to the fixed scroll, a cooling chamber which is
provided adjacently on the outer peripheral side of the motor
portion, and a high pressure chamber which is provided adjacently
on the outer peripheral side of the cooling chamber, so that gas
compressed by the fixed scroll and the movable scroll is supplied
to the high pressure chamber, wherein a cooling fluid is supplied
to the cooling chamber to cool both the gas and the motor
portion.
[0018] Namely, the scroll compressor with an electric motor
incorporated according to the present invention is characterized in
that a high pressure chamber, to which the compressed gas is
supplied, is provided on the outer peripheral side of the motor
portion and a cooling chamber, to which the cooling fluid is
supplied, is provided on the inner peripheral side of the high
pressure chamber. In other words, the motor portion, the annular
cooling chamber and the annular high pressure chamber are arranged
in this order in the radial direction, from the inner peripheral
side.
[0019] Since the high pressure chamber and the cooling chamber are
provided on the outer peripheral side of the motor portion and the
suction port of the gas is provided on the compressor portion side,
there is no fear that the suction gas introduced in the compressor
portion is heated by the cooling fluid whose temperature has risen
in the cooling chamber. Consequently, it is possible to prevent the
mass flow rate of the gas to be supplied to the fuel cell from
being reduced. Moreover, it is possible to effectively cool both
the gas and the motor portion by means of the single cooling
chamber.
[0020] The present invention may be more fully understood from the
description of preferred embodiments of the invention, as set forth
below, together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In the drawings;
[0022] FIG. 1 is an axial sectional view of a scroll compressor
with an electric motor incorporated, according to the present
invention; and
[0023] FIG. 2 is an axial sectional view of a known scroll
compressor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] An embodiment of the invention will be discussed below with
reference to the accompanying drawing. In FIG. 1 shows an axial
sectional view of a scroll compressor with an electric motor
incorporated, according to an embodiment of the invention. A
compression portion is provided in a housing 1. The housing 1 is
constituted by a cup-shaped front casing 2 of an aluminum alloy, a
cylindrical rear casing 3 of an aluminum alloy, a cup-shaped motor
casing 4 of an aluminum alloy and a bottom plate 41 of an aluminum
alloy. The front casing 2 is provided at its bottom center portion
with a discharge port 20a. The rear casing 3 is located at an open
end of the front casing 2 and is provided with a small diameter
portion, a large diameter portion with an end recess 3a, and a
disc-shaped separation portion 3b between the small diameter
portion and the large diameter portion. The motor casing 4 is
provided on its outer peripheral surface with an annular recess 4a
and an annular projection 4b adjacent thereto and is provided on
its bottom center portion with a hole. An open end of the motor
casing 4 is fitted in the inner peripheral surface of the large
diameter portion of the rear casing 3. The bottom plate 41 is
attached to the motor casing 4 to cover the bottom hole
thereof.
[0025] A high pressure chamber 25 is defined by closing the recess
3a, which is formed in the large diameter portion of the rear
casing 3 with the projection 4b on the outer peripheral surface of
the motor casing 4, in assembling the motor casing 4 to fit in the
inner peripheral surface of the large diameter portion of the rear
casing 3.
[0026] A gas passage 6 for highly pressurized gas extends between
the high pressure chamber 25 and the discharge port 20a of the
front casing 2. The gas passage 6 is provided with a steel
cylindrical elbow 60 connected to the discharge port 20a, a steel
pipe 61 connected to the elbow 60, a steel elbow 62 connected to
the steel pipe 61, a steel pipe 63 connected to the elbow 62, and a
steel elbow 64 connected to the steel pipe 63. The steel pipe 63 is
fitted at the other end in the large diameter portion of the rear
casing 3 and opens into the high pressure chamber 25. A discharge
pipe 80 is inserted in the large diameter portion of the rear
casing 3 and opens to the high pressure chamber 25.
[0027] In assembling the motor casing 4 to fit in the inner
peripheral surface of the large diameter portion of the rear casing
3, the inner peripheral surface of the large diameter portion of
the rear casing 3 covers the recess 4a of the motor casing 4 in the
axial direction to define an annular cooling chamber 26. A steel
inlet pipe 70 and a steel outlet pipe 71 extend through the
projection 4b of the motor casing 4 and open to the cooling chamber
26.
[0028] A motor portion 5 is provided in the motor casing 4 and is
constituted by an annular stator 50 on the inner peripheral surface
of the motor casing 4, a coil 51 wound in a slit (not shown) of the
stator 50, an annular rotor 52 made of a magnetic material and
arranged at the inner side of the stator 50, a part of the drive
shaft extending in the axial direction at the center portion of the
rotor 52, and a ball bearing which rotatably supports the drive
shaft 30 at the bottom portion of the motor casing 4.
[0029] The basic structure of the compressor portion of the scroll
compressor with an electric motor incorporated in the illustrated
embodiment is substantially described in FIG. 2.
[0030] In FIG. 3 of the embodiment of the invention, no end plate
20 is provided; the cooling chamber 26 and the high pressure
chamber 25 are provided on the outer peripheral side of the motor
portion 5; the drive shaft 30 extends to the motor portion 5; and
the rear casing 3 is different in shape from the rear casing in
FIG. 2.
[0031] The flow of air, as the gas for the scroll compressor with
an electric motor incorporated in the illustrated embodiment, will
be discussed below.
[0032] When the drive shaft is rotated by driving the electric
motor and a movable scroll 31 orbits. Air closed in a suction
portion 22 at the outer peripheral side of the movable scroll 31 is
gradually transferred to the center side of the movable scroll 31
and is compressed due to the orbit of the movable scroll 31 by
decreasing the volume of the space closing the air.
[0033] The air compressed by the fixed scroll 21 and the movable
scroll 31 is discharged into the high pressure gas passage 6 from
the discharge portion 23 through the discharge valve 24. The air
passing in the gas passage 6 is introduced in the annular high
pressure chamber 25. The air circulates in the high pressure
chamber 25 and is discharged to the outside of the compressor
through the discharge pipe 80.
[0034] The flow of water, as the cooling fluid for the scroll
compressor with an electric motor incorporated in the illustrated
embodiment, will be discussed below.
[0035] The water introduced in the annular cooling chamber 26
through the inlet pipe 70 circulates therein. During the
circulation of the water, the heat is transferred to the water from
the compressed air in the high pressure chamber 25 provided on the
outer peripheral side of the cooling chamber 26, and from the motor
portion 5 provided on the inner peripheral side of the cooling
chamber 26. Consequently, the water, whose temperature has risen,
is discharged to the outside of the compressor from the outlet pipe
71. There are externally provided a radiator which cools the heated
water and a pump which feeds the pressurized water, so that the
water cooled by the radiator is introduced again into the
compressor through the inlet pipe 70, although the details thereof
are not shown in the drawings.
[0036] In the illustrated embodiment, the housing is constituted by
the front casing 2, the rear casing 3, the motor casing 4, and the
bottom plate 41. In place of the housing which is made of an
assembly of a plurality of elements, it is alternatively possible
to form some of the elements integrally. Moreover, although the
fixed scroll 21 is formed at a boundary surface 2a of the front
casing 2 and is secured to the housing, it is alternatively
possible to arrange a separate member having a fixed scroll in the
housing. This alternative is included in the concept of securing
the fixed scroll to the housing.
[0037] Although air is used as the gas to be compressed by the
compressor portion in the illustrated embodiment, the kind of the
gas is not limited to a specific one. If further enhanced hermetic
sealing of the compressor portion is established, hydrogen gas or
the like, which is fuel used for the fuel cell, can be used.
[0038] The size and shape of the cooling chamber are not limited to
specific ones. For instance, in an arrangement in which the
radiator fins are provided in the cooling chamber, the heat
transfer area is increased and, hence, the cooling efficiency is
enhanced. Furthermore, it is possible to provide a corrugated
separation wall between the cooling chamber and the high pressure
chamber and/or between the cooling chamber and the motor portion in
order to further increase the heat transfer area.
[0039] In the illustrated embodiment, the cooling chamber 26 is
formed by fitting the motor casing 4 in the rear casing 3. With
this arrangement, the cooling chamber can be easily formed.
However, it is alternatively possible to use a separate member
which defines therein a cooling chamber and which is attached to
the motor casing. In this alternative, the cooling chamber is
highly liquid-tight due to the seamless wall thereof. The separate
member which defines therein a cooling chamber forms a part of the
housing.
[0040] The material of which the cooling chamber is formed is not
limited to a specific material. In the illustrated embodiment, the
cooling chamber is formed by a member made of an aluminum alloy.
The aluminum alloy exhibits a high heat transfer rate, thus leading
to an enhanced cooling efficiency. The cooling chamber can be
formed of a die casting.
[0041] Although water is used as the cooling fluid, the kind of the
cooling fluid is not limited to specific fluid. Any medium which is
liquid at the temperature of the environment in which the
compressor is used, and which does not corrode the material of the
equipment, can be appropriately selected. It is possible to use
pure water, which is produced by the fuel cell, as the cooling
fluid.
[0042] Although the special-purpose cooling circuit for the
compressor is used in the illustrated embodiment, it is possible to
add a cooling chamber to a cooling circuit provided in an
automobile or the like to cool other devices therein. Absence of an
additional cooling circuit contributes to reduction in the
accommodation space and manufacturing cost. Alternatively, it is
also possible to discharge the used cooling fluid without
recirculating the cooling fluid. Absence of a recirculating circuit
of the cooling fluid simplifies the compressor and reduces the
accommodation space.
[0043] Although the gas passage for highly pressurized gas is made
of a plurality of steel pipes and elbows in the illustrated
embodiment, it is possible to form the gas passage of a single
piece of pipe. The single piece of pipe contributes to an
enhancement of the sealing efficiency. Although the gas passage for
highly pressurized gas is provided outside of the housing in the
illustrated embodiment, it is possible to provide the gas passage
in the housing. If the gas passage is provided in the housing, no
interference with other devices, provided in an automobile or the
like, occurs so that the reliability can be enhanced and the
accommodation space can be reduced.
[0044] The kind and internal structure of the motor are not limited
to specific ones. Although an inverter-controlled motor is used in
the illustrated embodiment, it is possible to use a DC motor.
[0045] The shape of the rotor and the stator of the motor portion
and the arrangement of the coil and the magnetic material therein
are not specifically limited. Although the coil is located on the
stator side and the magnetic material is located on the rotor side,
in the illustrated embodiment, it is possible to use a motor in
which the magnetic material is located on the stator side and the
coil is located on the rotor side.
[0046] Although the rotary shaft of the motor is used as the drive
shaft of the movable scroll of the compressor portion in the
illustrated embodiment, it is alternatively possible to provide a
drive shaft of the movable scroll separate from the rotary shaft of
the motor. In this alternative, the drive shaft of the movable
scroll and the rotary shaft of the motor are connected by means of
a rotation transmission mechanism. The drive shaft in the present
invention is constituted by the rotary shaft of the motor, the
rotation transmission mechanism and the drive shaft of the movable
scroll. In order to change the number of revolutions of the rotary
shaft of the motor and the drive shaft of the movable scroll, it is
possible to provide a rotation change device in the rotation
transmission mechanism.
[0047] In a scroll compressor with an electric motor incorporated,
according to the present invention, the high pressure chamber and
the cooling chamber are provided on the outer peripheral side of
the motor portion of the housing, that is, the cooling chamber is
provided between the high pressure chamber and the motor portion.
Consequently, reduction in the mass flow rate of the discharge gas
of the compressor can be suppressed. Furthermore, it is possible to
cool both the discharge gas and the motor portion by a single
cooling chamber.
[0048] While the invention has been described by reference to
specific embodiments chosen for purpose of illustration, it should
be apparent that numerous modification could be made thereto by
those skilled in the art without departing from the basic concept
and scope of the invention.
* * * * *