U.S. patent application number 12/011285 was filed with the patent office on 2008-07-31 for electric compressor.
Invention is credited to Masao Iguchi, Masahiro Kawaguchi, Ken Suitou.
Application Number | 20080181791 12/011285 |
Document ID | / |
Family ID | 39321435 |
Filed Date | 2008-07-31 |
United States Patent
Application |
20080181791 |
Kind Code |
A1 |
Iguchi; Masao ; et
al. |
July 31, 2008 |
Electric compressor
Abstract
An electric compressor (10) is equipped with a motor chamber
(27) provided in a suction pressure region. The motor chamber (27)
is adjacent to an inverter accommodation chamber (101) with a first
housing (24) therebetween, and a cooling hole (130) extending from
the motor chamber (27) toward the inverter accommodation chamber
(101) is formed through the first housing (24). The cooling hole
(130) is a through-hole passing through the first housing (24). A
cooling medium in the motor chamber (27) flows into the cooling
hole (130) and comes into contact with a heat transfer plate (110),
thereby cooling the heat transfer plate (110) directly.
Inventors: |
Iguchi; Masao; (Aichi-ken,
JP) ; Kawaguchi; Masahiro; (Aichi-ken, JP) ;
Suitou; Ken; (Aichi-ken, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
3 WORLD FINANCIAL CENTER
NEW YORK
NY
10281-2101
US
|
Family ID: |
39321435 |
Appl. No.: |
12/011285 |
Filed: |
January 25, 2008 |
Current U.S.
Class: |
417/45 ; 417/366;
417/410.1 |
Current CPC
Class: |
F04C 29/045 20130101;
F04C 2240/30 20130101; F04C 23/008 20130101; F04C 2240/808
20130101; F04C 18/0215 20130101; F01C 21/10 20130101; F04C 28/08
20130101; F04C 29/0085 20130101 |
Class at
Publication: |
417/45 ;
417/410.1; 417/366 |
International
Class: |
F04B 39/06 20060101
F04B039/06; F04B 49/06 20060101 F04B049/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 2007 |
JP |
2007-018007 |
Claims
1. An electric compressor comprising: a compression mechanism
portion for sucking in fluid from a suction pressure region; an
electric motor for driving the compression mechanism portion; a
motor chamber provided in the suction pressure region for
accommodating the electric motor; an inverter assembly for
converting a direct current into a polyphase alternating current to
supply the converted current to the electric motor, the inverter
assembly controlling rotational frequency of the electric motor,
with the inverter assembly being provided with a substrate having
an electric circuit, electronic components connected to the
substrate, and a base for supporting the substrate; and an inverter
accommodation chamber for accommodating the inverter assembly and
removably fixing the inverter assembly; a housing separating the
motor chamber and the inverter accommodation chamber, the housing
having formed therethrough a through-hole extending from the motor
chamber toward the inverter accommodation chamber, the through-hole
being in contact at one end thereof with the base, with the motor
chamber and the inverter accommodation chamber being sealed from
each other around the through-hole.
2. The electric compressor according to claim 1, wherein the motor
chamber and the inverter accommodation chamber are sealed from each
other using an O-ring.
3. The electric compressor according to claim 1 or 2, wherein: the
electronic components include a switching element; and the
through-hole is provided in a vicinity of the switching element.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an electric compressor, and
more particularly, to an inverter for driving an electric
motor.
[0003] 2. Description of the Related Art
[0004] Electric compressors having a compression mechanism portion
equipped with an electric motor for driving the compression
mechanism portion, and also with an inverter for controlling and
driving the electric motor are known. In this kind of electric
compressor, the inverter is accommodated and fixed in an inverter
accommodation chamber. In some cases, this kind of electric
compressor is constructed so that respective members of the
inverter are irremovably fixed in position. For example, JP
2004-197688 A discloses such an electric compressor.
[0005] However, in the inverter of such a conventional electric
compressor as disclosed in JP 2004-197688 A, there is a problem in
that efficiency of cooling electronic components included in the
inverter, especially the switching elements is relatively low.
[0006] Therefore, temperature protection is required and hence
constructional complication is caused when, for example, switching
elements with low heatresisting temperatures are used.
Alternatively, high cost and constructional enlargement are caused
when switching elements with high heatresisting temperatures are
used.
SUMMARY OF THE INVENTION
[0007] The present invention has been made to solve the
above-mentioned problem, and it is therefore an object of the
present invention to provide an electric compressor that can
enhance the efficiency of cooling electronic components of an
inverter assembly.
[0008] In order to achieve the above-mentioned object, according to
the present invention, there is provided an electric compressor
including: a compression mechanism portion for sucking in fluid
from a suction pressure region; an electric motor for driving the
compression mechanism portion; a motor chamber provided in the
suction pressure region, for accommodating the electric motor; an
inverter assembly for converting a direct current into a polyphase
alternating current to supply the converted current to the electric
motor and for controlling rotational frequency of the electric
motor; and an inverter accommodation chamber for accommodating the
inverter assembly, wherein the inverter assembly is provided with a
substrate having an electric circuit, electronic components
connected to the substrate, and a base for supporting the
substrate, the inverter assembly removably fixed in the inverter
accommodation chamber, the motor chamber and the inverter
accommodation chamber are adjacent to each other with a housing
therebetween, the housing having formed therethrough a through-hole
extending from the motor chamber toward the inverter accommodation
chamber, the through-hole being in contact at one end thereof with
the base, with the motor chamber and the inverter accommodation
chamber being sealed from each other around the through-hole.
[0009] With this electric compressor, a cooling medium in the motor
chamber located in the suction pressure region, namely on a
low-temperature side, flows into the through-hole, passes through
the housing, and comes into contact with the base. Thus, the base
is directly cooled around the through-hole. The base functions as a
heat transfer plate, and further cools the electronic
components.
[0010] The electronic components include a switching element, and
the through-hole may be provided in the vicinity of the switching
element.
[0011] By adopting this construction, the switching element can be
cooled more efficiently. The switching element tends to reach a
higher temperature than the other elements constituting the
electronic components. Therefore, when the switching element can
thus be cooled in a pinpoint manner, the electronic components can
be cooled as a whole more efficiently.
[0012] The inverter assembly may further be equipped with the base
for supporting the substrate, and the base may be in contact with
one end of the through-hole.
[0013] By adopting this construction, the base serving as the heat
transfer plate can also be utilized as a constructional element for
sealing the motor chamber and the inverter accommodation chamber
from each other. As a result, constructional simplification is
achieved.
[0014] According to the present invention, the cooling medium in
the suction pressure region flows through a cooling hole and comes
into contact with the heat transfer plate of the inverter assembly,
thereby cooling the heat transfer plate directly. Therefore, the
efficiency of cooling the electronic components of the inverter
assembly can be enhanced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In the accompanying drawings:
[0016] FIG. 1 is a diagram showing a construction of an electric
compressor according to a first embodiment of the present
invention; and
[0017] FIG. 2 is a diagram showing a construction of an inverter
assembly included in the electric compressor of FIG. 1 and the
periphery thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] An embodiment of the present invention will be described
hereinafter with reference to the accompanying drawings.
First Embodiment
[0019] FIG. 1 shows an electric compressor 10 according to the
first embodiment of the present invention.
[0020] The electric compressor 10 is provided with a first housing
24 and a second housing 25. The first housing 24 and the second
housing 25 are fixed to each other by bolts 16. An inner surface of
the first housing 24 is generally in the shape of a bottomed
cylinder including a cylindrical portion 24f and a bottom portion
24g. The bottom portion 24g is provided with a cylindrical shaft
support portion 24h.
[0021] In FIG. 1, the right side of the figure, namely the second
housing 25 side, is defined as the front, and the left side of the
figure, namely the bottom portion 24g side of the first housing 24,
is defined as the rear.
[0022] The electric compressor 10 is equipped with a fixed scroll
11, a rotary scroll 12, and a compression chamber 13 formed by the
fixed scroll 11 and the rotary scroll 12. The fixed scroll 11 has a
disc-shaped fixed base 11a, a spiral fixed lap 11b provided upright
on the fixed base 11a, and a fixed lap outermost wall 11c. A
discharge port 47 is formed through the center of the fixed base
11a.
[0023] In the electric compressor 10, a compression mechanism
portion is composed of the fixed scroll 11, the rotary scroll 12,
and the compression chamber 13. The compression mechanism portion
sucks in fluid from a suction pressure region, compresses the
fluid, and discharges the fluid to a discharge pressure region. It
should be noted herein that the suction pressure region is a region
through which the fluid sucked in from outside the electric
compressor 10 flows before flowing into the compression chamber 13,
and that the discharge pressure region is a region through which
the fluid compressed in the compression chamber 13 flows before
flowing out of the electric compressor 10.
[0024] The rotary scroll 12 is composed of a disc-shaped rotary
base 12a, and a spiral rotary lap 12b provided upright on the
rotary base 12a. A holding portion 12c, which is in the shape of a
bottomed cylinder, for holding a ball bearing 17, is provided at a
center of a back side of the rotary base 12a.
[0025] The electric compressor 10 is further equipped with a drive
crank mechanism 19 for rotating the rotary scroll 12 (rotational
movement), and pins 20 for preventing the rotary scroll 12 from
spinning. The pins 20, which are mounted on a shaft support member
15, are provided so as to freely engage with an annular recess
portion 12d of the rotary scroll 12.
[0026] The drive crank mechanism 19 is composed of the holding
portion 12c, a crank pin 22a of a drive shaft 22, and the ball
bearing 17 for bearing the crank pin 22a via a bush 18.
[0027] The drive shaft 22 penetrates the center of an electric
motor 26. The electric motor 26, which drives the compression
mechanism portion, is a three-phase synchronous motor equipped with
the drive shaft 22, a rotor 28 fitted on the drive shaft 22, and a
stator 30 provided on an outer peripheral side of the rotor 28 and
having a coil 29 wound therearound.
[0028] By making a part of the first housing 24 concave, an
inverter accommodation chamber 101 is provided in an outer surface
of the first housing 24 on a rear side thereof. The electric
compressor 10 includes an inverter assembly 100 accommodated in the
inverter accommodation chamber 101. A detailed construction of the
inverter assembly 100 will be described later with reference to
FIG. 2. In FIG. 1, only a heat transfer plate 110 is illustrated
for the sake of simplification.
[0029] The inverter assembly 100 is electrically connected to the
electric motor 26 via a hermetic terminal 122 (which will be
described later with reference to FIG. 2) provided in the first
housing 24.
[0030] The inverter assembly 100 converts a direct-current power
supplied from the outside into a polyphase alternating-current
power to supply the converted polyphase alternating-current power
to the electric motor 26, and controls the rotational frequency of
the electric motor 26.
[0031] A cover 150 is mounted onto the first housing 24 so as to
cover the inverter assembly 100. The cover 150 isolates the
inverter accommodation chamber 101 from the outside. It should be
noted herein that the cover 150 constitutes an outer wall of the
electric compressor 10. That is, the cover 150, the first housing
24, and the second housing 25 isolate the inside of the electric
compressor 10 from the outside. The inverter accommodation chamber
101 is formed with an outer wall thereof constituted by the cover
150 and the first housing 24.
[0032] When the electric compressor 10 is in use, the electric
compressor 10 is disposed such that a viewing direction from the
drive shaft 22 toward the inverter assembly 100 coincides with an
upward direction in FIG. 1. That is, the inverter assembly 100 is
disposed above the first housing 24.
[0033] The drive shaft 22 is supported, at an end thereof on the
drive crank mechanism 19 side, by the shaft support member 15 via a
ball bearing 22e, and at a rear end thereof by the shaft support
portion 24h of the first housing 24 via a ball bearing 22f. A seal
22g, which is provided behind the ball bearing 22e, seals a gap
between the drive shaft 22 and the shaft support member 15.
[0034] A fluid as a cooling medium flows through a space covered by
the first housing 24 and the second housing 25 described above. In
this space, a motor chamber 27 is defined by the first housing 24
and the shaft support member 15, and a crank chamber 21 is defined
by the first housing 24, the second housing 25, and the shaft
support member 15. The motor chamber 27 and the crank chamber 21
communicate with each other through a channel (not shown).
[0035] It should be noted herein that, as shown in FIGS. 1 and 2,
the motor chamber 27 and the inverter accommodation chamber 101 are
adjacent to each other with the first housing 24 therebetween.
[0036] A discharge chamber 32, which is defined by the fixed scroll
11 and the second housing 25, is provided on the other side of the
compression chamber 13 with respect to the discharge port 47. The
cooling medium compressed in the compression chamber 13 is
discharged to the discharge chamber 32 via the discharge port 47. A
reed valve 34 and a retainer 36 are provided in the discharge
chamber 32 to prevent the cooling medium from flowing backward,
namely, from the discharge chamber 32 toward the discharge port 47.
The discharge chamber 32 has an external opening 32a communicating
with the outside. The inside and outside of the electric compressor
10 communicate with each other through the external opening
32a.
[0037] In the electric compressor 10 constructed as described
above, the cooling medium flows from the outside into the motor
chamber 27 via an intake port (not shown). The cooling medium
further flows from the motor chamber 27 into the crank chamber 21
and the compression chamber 13, which communicates with the crank
chamber 21, via an intake channel (not shown). In the compression
chamber 13, the cooling medium is compressed through rotation of
the rotary scroll 12 resulting from rotation of the drive shaft 22.
The compressed cooling medium flows from the discharge port 47 into
the discharge chamber 32 and then is discharged to the outside via
the external opening 32a.
[0038] FIG. 2 shows the construction of the inverter assembly 100
according to the first embodiment of the present invention and the
periphery thereof.
[0039] FIG. 2 is a partial sectional view taken along the line
II-II of FIG. 1.
[0040] The cover 150 and the first housing 24 sandwich a gasket 120
therebetween, so the inverter accommodation chamber 101 is isolated
from the outside. The gasket 120 is a plate-shaped member composed
of a core as an iron plate and a rubber material surrounding the
core.
[0041] The inverter assembly 100 includes a substrate 112 having an
electric circuit, and the heat transfer plate 110 as a base for
supporting the substrate 112. The heat transfer plate 110, which is
made of a material exhibiting relatively high thermal conductivity,
for example, aluminum, serves as an intermediary for transferring
heat between the motor chamber 27 and the inverter accommodation
chamber 101. The substrate 112 is fixed to the heat transfer plate
110 by screws 128.
[0042] The cover 150, the heat transfer plate 110, and the first
housing 24 are fastened together and fixed by screws 118.
Accordingly, the heat transfer plate 110 is mounted to the first
housing 24 in a close contact state. The screws 118 are provided at
positions different from the section of FIG. 2, so those regions
which are fastened together are not visible in FIG. 2. For the sake
of explanation, only screw heads of the screws 118 are illustrated
in FIG. 2.
[0043] The inverter assembly 100 also includes, as electronic
components, a capacitor 114, a coil 16, the hermetic terminal 122,
insulated gate bipolar transistors (IGBT's) 124 and 125 as
switching elements, and a varistor (not shown).
[0044] The capacitor 114 is designed as, for example, an
electrolytic capacitor, and has leads 114a. The leads 114a are
soldered on the substrate 112 to electrically connect the capacitor
114 to the electric circuit of the substrate 112. The capacitor 114
is fixed to the substrate 112 by the leads 114a and solder (not
shown) around the leads 114a, and glued and fixed to the heat
transfer plate 110 by a resinous adhesive 114b.
[0045] The coil 116 has leads 116a. The leads 116a are soldered to
the substrate 112 to electrically connect the coil 116 to the
electric circuit of the substrate 112. The coil 116 is fixed to the
substrate 112 by the leads 116a and solder (not shown) around the
leads 116a. Further, the coil 116 is glued and fixed to the heat
transfer plate 110 by a resinous adhesive 116b.
[0046] The IGBT's 124 and 125 have leads 124a and 125a,
respectively. The leads 124a and 125a are soldered to the substrate
112 to electrically connect the IGBT's 124 and 125 to the electric
circuit of the substrate 112, respectively. The IGBT's 124 and 125
are fixed to the heat transfer plate 110 by screws 126 and 127,
respectively.
[0047] The hermetic terminal 122 has leads 122a. The leads 122a are
soldered to the substrate 112 to electrically connect the hermetic
terminal 122 to the electric circuit of the substrate 112. The
hermetic terminal 122 is fixed to the heat transfer plate 110.
Although not shown, the hermetic terminal 122 electrically connects
the inverter assembly 100 to the electric motor 26 (see FIG. 1) in
the first housing 24, and isolates the inverter accommodation
chamber 101 from the motor chamber 27, namely, a space in which the
electric motor 26 is accommodated, in an airtight manner.
[0048] In this manner, the substrate 112, the capacitor 114, and
the coil 116 are supported by the heat transfer plate 110 and the
inverter assembly 100 is assembled. As described above, the heat
transfer plate 110 is fixed to the first housing 24 by the screws
118. The inverter assembly 100 is thereby fixed to the first
housing 24. The fixing is removable screwing by the screws 118.
[0049] A cooling medium channel including at least part of the
motor chamber 27 is formed between the first housing 24 and the
stator 30 (see FIG. 1), and the cooling medium flows through the
cooling medium channel. The cooling medium cools the heat transfer
plate 110 through the first housing 24, thereby cooling the
inverter assembly 100. The cooling medium also cools the electric
motor 26 through the stator 30.
[0050] The cooling medium channel is a low pressure-side channel of
the electric compressor 10. In other words, the motor chamber 27 is
provided in the suction pressure region of the electric
compressor
[0051] A cooling hole 130 extending from the motor chamber 27
toward the inverter accommodation chamber 101 is formed so as to
pass through the first housing 24 immediately below the IGBT 125.
The cooling hole 130 is a through-hole penetrating the first
housing 24. An upper end opening 130a of the cooling hole 130 is in
contact with the heat transfer plate 110, so the heat transfer
plate 110 is in contact with the cooling medium in the suction
pressure region. The cooling hole 130 is in the shape of, for
example, a hollow cylinder, but may be in another shape.
[0052] A sealing structure for sealing the motor chamber 27 and the
inverter accommodation chamber 101 from each other is provided
around the cooling hole 130. In the example of FIG. 2, an O-ring
groove 130b is provided around the upper end opening 130a of the
cooling hole 130, and an O-ring 130c as a sealing member is
disposed in the O-ring groove 130b. The O-ring 130c, which is
sandwiched by the first housing 24 and the heat transfer plate 110,
isolates the motor chamber 27 and the inverter accommodation
chamber 101 from each other around the cooling hole 130.
[0053] In assembling the electric compressor 10, the inverter
assembly 100 is first assembled so as to be integrated as one body.
The assembly may be carried out in any sequence. For example, the
respective electronic components are first mounted on the heat
transfer plate 110, the substrate 112 is then fixed to the heat
transfer plate 110 by the screws 128, and the respective electronic
components are connected to the substrate 112.
[0054] After having been assembled, the inverter assembly 100 is
incorporated into the electric compressor 10. The incorporation is
carried out by fastening and fixing the cover 150, the heat
transfer plate 110, and the first housing 24 together by the screws
118.
[0055] It should be noted herein that, as described above, gel is
not encapsulated in the inverter accommodation chamber 101.
Therefore, by removing the screws 118, the heat transfer plate 110
is released from the first housing 24, so the inverter assembly 100
can be removed. That is, the integral-type inverter assembly 100 is
a cartridge-type assembly designed to be removable in the electric
compressor 10.
[0056] With this electric compressor 10 constructed as described
above, the cooling medium in the suction pressure region of the
electric compressor 10, namely, on the low-temperature side thereof
flows from the motor chamber 27 through the cooling hole 130 and
comes into contact with the heat transfer plate 110 at the upper
end 130a thereof. Thus, the heat transfer plate 110 is directly
cooled around the cooling hole 130. The cooling hole 130 is formed
immediately below the IGBT 125, so the cooling medium in the
cooling hole 130 efficiently cools the IGBT 125 through the heat
transfer plate 110. Thus, the electric compressor 10 can improve
the performance of cooling the IGBT 125 and the inverter assembly
100 including the IGBT 125.
[0057] Due to the enhancement of the cooling efficiency, the IGBT
125 can be kept at a lower temperature, so the heatresisting
temperature required of the IGBT 125 can be lowered. Thus,
switching elements that are smaller in size or lower in cost can be
adopted.
[0058] Further, temperature protection is not required even in the
case where switching elements with a low heatresisting temperature
are used. Therefore, the inverter assembly 100 can be used in a
wider operational range, namely, in wider varieties of operational
states.
[0059] The cooling medium directly cools the heat transfer plate
110 without the intermediary of the first housing 24, so cooling
efficiency can be enhanced compared to that with a construction in
which the cooling medium cools the heat transfer plate 110
indirectly through the first housing 24.
[0060] In the electric compressor 10, there is no gel encapsulated
in the inverter accommodation chamber 101, and the inverter
assembly 100 is removable, so maintenance can be carried out more
easily than with a conventional construction in which an inverter
assembly is irremovably fixed. Thus, cooling efficiency can be
enhanced as described above while facilitating maintenance.
[0061] In some conventional constructions, fins or the like are
formed to cool the inverter. In such constructions, the shape of a
casting mold for forming the fins or the like is complicated, so it
is difficult to carry out maintenance of the casting mold. In the
electric compressor 10 according to this embodiment, the cooling
hole 130 can be formed by forming the through-hole through the
first housing 24. Therefore, a casting mold having a relatively
simple shape can be used, so it is easier to carry out the
maintenance.
[0062] In the aforementioned first embodiment of the present
invention, referring to the example of FIG. 2, the cooling hole 130
is located immediately below the IGBT 125. However, the cooling
hole 130 does not have to be located immediately below the IGBT
125. For example, the cooling hole 130 may be located below or
close to the IGBT 125. In addition, the cooling hole 130 may be
provided anywhere as long as the efficiency of cooling the IGBT 125
is enhanced.
[0063] Further, the cooling hole 130 may also be designed to not
cool the IGBT 125 but to cool at least one of the electronic
components, for example, the capacitor 114 or the coil 116. In this
case, the cooling hole 130 may be provided immediately below or
close to the capacitor 114 or the coil 116, or at such a position
that the efficiency of cooling the capacitor 114 or the coil 116 is
enhanced. In such a construction as well, the inverter assembly 100
including the electronic components can be efficiently cooled as in
the case of the construction shown in FIG. 2.
[0064] In the example of FIG. 2, only the single cooling hole 130
is provided for the IGBT 125. However, a cooling hole 130 may be
provided for each of a plurality of elements. For example, a
cooling hole may be provided for each of the IGBT's 124 and 125,
and a cooling hole may be provided for each of the other electronic
components. Further, a plurality of cooling holes 130 may be
provided for each of the electronic components.
[0065] The electric compressor 10 is exemplified as a scroll-type
compressor. However, the type of the electric compressor 10 may be
changed as long as the electric compressor 10 is equipped with a
compression mechanism portion for compressing a fluid.
* * * * *