[Technical Field]
[0001] The present invention relates to an electric compressor where a compression part
and an electric motor which constitutes a drive part are integrally formed.
[Background Art]
[0002] JP-A-2002-174178 discloses an electric compressor for compressing a refrigerant where a compression
part and a motor are integrally formed, wherein a motor drive circuit is mounted on
an outer surface of a surrounding wall of a refrigerant gas suction passage, and heat
radiation fins are mounted on an inner surface of a motor drive circuit mounting portion
of the surrounding wall of the refrigerant gas suction passage. The motor drive circuit
is configured to be cooled by a refrigerant gas which flows through the surrounding
wall of the refrigerant gas suction passage and the heat radiation fins.
[0003] An electric compressor disclosed in
JP-A-2008-184947 is configured such that the electric compressor includes a motor chamber arranged
in a suction pressure region, the motor chamber and an inverter housing chamber are
arranged adjacent to each other with a first housing sandwiched therebetween, a cooling
hole which extends toward the inverter housing chamber from the motor chamber is formed
in the first housing, the cooling hole is a through hole which penetrates the first
housing, and a refrigerant in the motor chamber flows into the cooling hole and comes
into contact with a heat transfer plate thus directly cooling the heat transfer plate
whereby an electronic part cooling effect can be enhanced.
[0004] An electric compressor disclosed in
JP-A-2010-59809 is configured such that the electric compressor includes a motor housing, an inverter
housing is joined to a bottom portion of the motor housing which forms a rear-side
end portion of the motor housing, an inverter housing chamber is defined in the inside
of the inverter housing, and an inverter is housed in the inverter housing chamber
in a state where the inverter is fixed to a bottom portion of the inverter housing
chamber.
[Citation List]
[Patent Literature]
[Summary of Invention]
[Technical Problem]
[0006] As can be understood from the above-mentioned patent
JP-A-2002-174178,
JP-A-2008-184947 and
JP-A-2010-59809, in the conventional electric compressor, a board on which the inverter circuit is
wired (inverter circuit board) is arranged and fixed in the inverter housing chamber
which is defined in a partitioned manner from a space where the electric motor is
housed by a wall portion. Electronic parts such as switching elements mounted in the
inverter circuit generate a large amount of heat and hence, for the purpose of enhancing
a cooling effect by improving thermal conductivity of the electronic parts, the switching
elements and the like are arranged in a state where the switching elements and the
like are brought into close contact with the wall portion in general. Further, with
respect to the electric compressors disclosed in
JP-A-2002-174178,
JP-A-2008-184947 and
JP-A-2010-59809, a bearing which rotatably supports a rotary shaft of the electric motor is press-fitted
into a motor-side wall portion of the inverter housing chamber.
[0007] In the conventional electric compressor, when the bearing is press-fitted into the
wall portion of the inverter housing chamber after the inverter circuit board is fixed
to the wall portion of the inverter housing chamber, a press-fit load generated at
the time of press fitting cannot be supported by a portion of a wall portion of the
inverter housing chamber positioned behind a press-fitting portion of the bearing
(a center portion of a wall portion of the inverter housing chamber) and hence, there
is a fear that the wall portion of the inverter housing chamber is largely deformed.
When the wall portion is deformed, there is a possibility that a drawback arises in
that a close contact state between an element which requires heat radiation and the
wall portion is deteriorated so that an element cooling effect is lowered or a drawback
that an element is broken. To prevent the occurrence of such a drawback, it is necessary
to press-fit the bearing before the inverter circuit board (the element which requires
heat radiation) is mounted or it is necessary to increase a thickness of the wall
portion of the inverter housing chamber.
[0008] Further, when the inverter circuit board is mounted after the bearing is press-fitted
into the wall portion of the inverter housing chamber, there arises a risk that the
bearing is exposed to dust, moisture or oil at the time of shifting step from one
step to another step such as the transfer of the inverter circuit board.
[0009] Accordingly, it is an object of the present invention to provide an electric compressor
having the structure which enables press-fitting of a bearing into a wall portion
of an inverter housing chamber after an inverter circuit board is mounted on the wall
portion of the inverter housing chamber while preventing an effect of cooling switching
elements and the like mounted on an inverter circuit from lowering or the switching
elements and the like from breaking, and also preventing the increase of a thickness
of the wall portion.
[Solution to Problem]
[0010] Accordingly, the present invention provides an electric compressor which includes:
a compression mechanism; an electric motor for driving the compression mechanism;
an inverter circuit for driving the electric motor; and a housing in which a compression
mechanism housing portion for housing the compression mechanism, an electric motor
housing portion for housing the electric motor, and an inverter circuit housing portion
for housing the inverter circuit are defined, wherein a wall portion is provided between
the electric motor housing portion and the inverter circuit housing portion, a bearing
which rotatably and pivotally supports a rotary shaft of the electric motor is press-fitted
into the wall portion on an electric motor housing portion side of the wall portion,
an inverter circuit board on which the inverter circuit is wired is provided on an
inverter circuit housing portion side of the wall portion, and the inverter circuit
housing portion is closed by a lid member, wherein the improvement is characterized
in that at least one pillar is provided between the wall portion and the lid member.
[0011] Due to such a constitution, a load applied to the wall portion at the time of press-fitting
the bearing can be received by the pillar and hence, even when the bearing is press-fitted
into the wall portion after the inverter circuit board is mounted on the wall portion,
a load (press-fitting force) applied to the inverter circuit board can be received
by the lid member by way of the pillar whereby it is possible to prevent an inverter
circuit cooling effect from lowering and the switching element or the like mounted
on the inverter circuit board from breaking.
[0012] It is desirable that the inverter circuit board is mounted on the wall portion by
way of the pillar. To realize such a constitution, a seat for holding the inverter
circuit board is formed on the pillar, and the inverter circuit board is fixed to
the seat.
[0013] The pillar is integrally formed with the wall portion and extends from the wall portion,
and a distal end of the pillar is brought into contact with the lid member.
[Advantageous Effects of Invention]
[0014] According to the present invention, the inverter circuit board is fixed to the wall
portion between the inverter circuit housing portion and the electric motor housing
portion by way of the pillar and hence, a load generated at the time of press-fitting
the bearing can be supported by the wall portion and the lid member whereby a bearing
press-fitting operation can be performed after mounting the inverter circuit board.
Accordingly, the present invention can acquire an advantageous effect that a risk
that the bearing is exposed to dust, moisture or oil after mounting the bearing is
small. Further, a press-fitting force is not transmitted to an electric element such
as a switching element which requires heat radiation at the time of press-fitting
the bearing and hence, the present invention can acquire an advantageous effect that
a risk that an inverter circuit cooling effect is lowered due to the deterioration
of a close contact state between the wall portion and the electric element or the
electric element is broken is small. Still further, a press-fitting force generated
at the time of press-fitting the bearing is supported by the pillar and hence, it
is unnecessary to increase a thickness of the wall portion whereby the present invention
can acquire an advantageous effect that a heat radiation effect at the wall portion
can be increased. Still further, the inverter circuit board is held at and fixed to
the seat formed on the pillar and hence, the present invention can acquire an advantageous
effect that the structure for fixing the inverter circuit board can be simplified.
[Brief Description of Drawings]
[0015]
- Fig. 1 is a schematic constitutional view of an electric compressor according to an
embodiment of the present invention;
- Fig. 2 is an explanatory view showing an inverter circuit housing portion of the electric
compressor according to the embodiment of the present invention;
- Fig. 3 is a schematic constitutional view for explaining the structure of the present
invention.
[Description of Embodiments]
[0016] Hereinafter, an embodiment of the present invention is explained in conjunction with
drawings.
[Embodiment]
[0017] As shown in Fig. 1, an electric compressor 1 according to the embodiment of the present
invention constitutes a part of a refrigerating cycle not shown in the drawing, for
example. The electric compressor 1 is provided for compressing a refrigerant and for
circulating the refrigerant in the refrigerating cycle. The electric compressor 1
is constituted of a compression mechanism housing portion 2 in which a compression
mechanism 20 is housed, an electric motor housing portion 3 in which an electric motor
30 for driving the compression mechanism 20 is housed, and an inverter circuit housing
portion 4 in which an inverter circuit board 40 where an inverter circuit for driving
the electric motor 30 is wired is housed.
[0018] The compression mechanism housing portion 2 includes a compression mechanism housing
block 22 which houses the compression mechanism 20 therein and defines a discharge
space 21 therein. In this embodiment, the compression mechanism 20 is a scroll-type
compression mechanism which is constituted of a fixed scroll member 23 which is fixed
to the compression mechanism housing block 22 by fitting, and a swing scroll member
24 which is meshed with the fixed scroll member 23 thus defining a compression space
25. However, the compression mechanism 20 is not particularly limited to a scroll-type
compression mechanism.
[0019] The electric motor housing portion 3 includes an electric motor housing block 31
which is joined and fixed to the compression mechanism housing block 22 using bolts
or the like and houses the electric motor 30 therein. In this embodiment, the electric
motor 30 is constituted of a plurality of stators 32 which are fixed to the electric
motor housing block 31 and around which coils connected to the inverter circuit wired
on the inverter circuit board 40 are wound, and a plurality of magnet-made rotors
33 which are fixed to a rotary shaft 34 and are arranged to face the stators 32 in
an opposed manner. Due to such a constitution, the rotor 33 is rotated by a rotating
magnetic field generated by the stators 32 with the supply of electric power outputted
from the inverter circuit so that the rotary shaft 34 is rotated.
[0020] The rotary shaft 34 is rotatably and pivotally supported by bearings 36, 37. An eccentric
shaft 35 is provided to one end of the rotary shaft 34 in an eccentric manner. The
swing scroll member 24 is swung due to the cooperative operation of the revolution
of the eccentric shaft 35 brought about by the rotation of the rotary shaft 34 and
an Oldham's mechanism 26 so that a volume of a compression space 25 is gradually decreased
from the outer peripheral direction to the center direction thus compressing a sucked
refrigerant. Further, a balance weight 38 for taking a rotary balance of the eccentric
shaft 35 is formed on the eccentric shaft 35.
[0021] As shown in Fig. 1 and Fig. 2, the inverter circuit housing portion 4 is constituted
of an inverter circuit housing block 41 which is connected and fixed to the electric
motor housing portion 3. The inverter circuit housing block 41 is constituted of a
wall portion 42 which is positioned between the inverter circuit housing portion 4
and the electric motor housing portion 3, and a peripheral wall portion 44 which defines
a housing space 43 in which the inverter circuit board 40 is housed. An end surface
of the housing space 43 in the axial direction is closed by a lid member 45. Further,
a bearing support portion 46 in which the bearing 37 is press-fitted is formed on
the wall portion 42 in an extending manner.
[0022] A drive circuit module 60 which is constituted by forming switching elements of the
inverter circuit into a module is arranged on a wall portion 42 side of the inverter
circuit board 40. Elements which generate a large amount of heat are integrated on
the drive circuit module 60. Accordingly, the drive circuit module 60 is brought into
close contact with a flat mounting surface 61 formed on the wall portion 42 by way
of a heat conductive material such as silicon grease, is fixed to the mounting surface
61 of the wall portion 42 by bolts 62 so as to hold such a state, and is cooled by
a sucked refrigerant which flows in the inside of the electric motor housing block
31 through the wall portion 42.
[0023] According to the present invention, in the electric compressor 1 having the above-mentioned
constitution, at least one pillar (three pillars in this embodiment) 50 are integrally
formed with the wall portion 42 in a state where the pillars 50 extend toward the
above-mentioned lid member 45 side from the wall portion 42 of the inverter circuit
housing block 41. As shown in Fig. 3, the pillars 50 extend from the wall portion
42, and a seat 51 for holding the inverter circuit board 40 at predetermined position
is formed on the pillar 50. The inverter circuit board 40 is mounted on the seats
51, and is fixed by washers 53. The pillars 50 penetrate the inverter circuit board
40 and extend toward the lid member 45, and end portions 52 of the pillars 50 are
brought into contact with the lid member 45.
[0024] Due to such a constitution, at the time of press-fitting the bearing 37 into the
bearing support portion 46, a load applied to the wall portion 42 is supported by
the lid member 45 by way of the pillars 50 and hence, it is possible to eliminate
a possibility that an effect of cooling electronic parts arranged on the inverter
circuit board 40, particularly electric elements such as switching elements which
require heat radiation is lowered or a possibility that the electronic part is broken.
Accordingly, a press-fitting operation of the bearing 37 can be performed after the
inverter circuit board 40 is arranged on the inverter circuit housing portion 4 before
press-fitting the bearing.
[0025] Further, by adopting the structure where the seat is formed on the respective pillars
50 and the inverter circuit board 40 is held and fixed by the washers, the fixing
structure of the inverter circuit board can be simplified.
[Reference Signs List]
[0026]
- 1:
- electric compressor
- 2:
- compression mechanism housing portion
- 3:
- electric motor housing portion
- 4:
- inverter circuit housing portion
- 20:
- compression mechanism
- 21:
- discharge space
- 22:
- compression mechanism housing block
- 23:
- fixed scroll member
- 24:
- swing scroll member
- 25:
- compression space
- 26:
- Oldham's mechanism
- 30:
- electric motor
- 31:
- electric motor housing block
- 32:
- stator
- 33:
- rotor
- 34:
- rotary shaft
- 35:
- eccentric shaft
- 36, 37:
- bearing
- 38:
- balance weight
- 40:
- inverter circuit board
- 41:
- inverter circuit housing block
- 42:
- wall portion
- 43:
- housing space
- 44:
- peripheral wall portion
- 45:
- lid member
- 46:
- bearing support portion
- 50:
- pillar
- 51:
- seat
- 52:
- end portion
- 53:
- washer