U.S. patent application number 11/887691 was filed with the patent office on 2009-06-11 for scroll fluid machine.
This patent application is currently assigned to SANDEN CORPORATION. Invention is credited to Yoshitaka Koitabashi, Shigeyuki Koyama, Tomokazu Naruta, Kou Tsukamoto.
Application Number | 20090148314 11/887691 |
Document ID | / |
Family ID | 37073316 |
Filed Date | 2009-06-11 |
United States Patent
Application |
20090148314 |
Kind Code |
A1 |
Koitabashi; Yoshitaka ; et
al. |
June 11, 2009 |
Scroll Fluid Machine
Abstract
An electric motor-driven scroll compressor as a fluid machine
includes a housing (10) containing a scroll unit (20) and an
armature (38) for driving the scroll unit (20), and a refrigerant
conduit located inside the housing (10) to guide a refrigerant
toward the scroll unit (20). The refrigerant conduit includes a
helical groove (64) as part thereof. The helical groove (64) is
formed in the outer peripheral surface of a rotor (54) constituting
the armature (38) and has opposite ends opening in the respective
opposite end faces of the rotor (54).
Inventors: |
Koitabashi; Yoshitaka;
(Saitama, JP) ; Tsukamoto; Kou; (Gunma, JP)
; Naruta; Tomokazu; (Gunma, JP) ; Koyama;
Shigeyuki; (Gunma, JP) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE LLP
551 FIFTH AVENUE, SUITE 1210
NEW YORK
NY
10176
US
|
Assignee: |
SANDEN CORPORATION
Gunma
JP
|
Family ID: |
37073316 |
Appl. No.: |
11/887691 |
Filed: |
March 29, 2006 |
PCT Filed: |
March 29, 2006 |
PCT NO: |
PCT/JP2006/306507 |
371 Date: |
October 1, 2007 |
Current U.S.
Class: |
417/366 ;
417/368; 417/372; 417/410.5 |
Current CPC
Class: |
F04C 29/0085 20130101;
F04C 29/045 20130101; F04C 2240/803 20130101; F04C 23/008 20130101;
F04C 18/0215 20130101 |
Class at
Publication: |
417/366 ;
417/368; 417/372; 417/410.5 |
International
Class: |
F04C 29/04 20060101
F04C029/04; F04C 18/02 20060101 F04C018/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2005 |
JP |
2005-106098 |
Claims
1. A scroll fluid machine comprising: a housing; a scroll unit
contained in said housing, said scroll unit having a fixed scroll
and a movable scroll cooperating with each other to compress a
working fluid; an armature contained in said housing adjacently to
the scroll unit and including a rotor for revolving the movable
scroll, the rotor having a peripheral surface and opposite end
faces; and a fluid conduit located inside said housing to guide the
working fluid toward said scroll unit through the armature and
including a helical groove formed in the peripheral surface of the
rotor, the helical groove having opposite ends opening in the
respective opposite end faces of the rotor.
2. The scroll fluid machine according to claim 1, wherein the
helical groove has a helix direction such that when the rotor is
rotated, the working fluid in the helical groove is forced toward
said scroll unit.
3. The scroll fluid machine according to claim 2, wherein said
scroll unit is a compression unit for a refrigeration circuit, and
said fluid conduit guides a refrigerant to be returned to said
compression unit.
4. The scroll fluid machine according to claim 2, wherein the
peripheral surface of the rotor is an outer peripheral surface of
the rotor.
5. The scroll fluid machine according to claim 4, wherein said
scroll unit is a compression unit for a refrigeration circuit, and
the fluid conduit guides a refrigerant to be returned to said
compression unit.
6. The scroll fluid machine according to claim 2, wherein the rotor
has a laminated structure obtained by laminating ring-shaped
magnetic steel sheets one upon another in an axial direction of the
rotor, and each of the magnetic steel sheets has a helical
groove-forming notch cut in a peripheral edge thereof constituting
the peripheral surface of the rotor.
Description
TECHNICAL FIELD
[0001] The present invention relates to scroll fluid machines, and
more particularly, to a scroll fluid machine suited for use as a
scroll compressor incorporated in a refrigeration circuit of an
automotive air-conditioning system to compress a refrigerant.
BACKGROUND ART
[0002] A scroll compressor of this type is driven by the engine or
electric motor of a motor vehicle. Compared with the engine-driven
compressor, the electric motor-driven compressor is easy to adjust
the displacement of the refrigerant, irrespective of engine load,
and thus is superior in that the temperature in the passenger
compartment of the vehicle can be finely controlled.
[0003] Also, since this type of scroll compressor is mounted on a
vehicle, there has been a demand for a compressor as compact in
size as possible. An electric motor-driven scroll compressor
disclosed in Unexamined Japanese Patent Publication No. 2003-129983
includes a housing used in common for the scroll unit and the
electric motor, and the scroll unit and the armature of the
electric motor are contained in the common housing.
[0004] During rotation of the electric motor, the armature
generates heat, and if the temperature of the armature excessively
rises, the performance of the motor lowers. Accordingly, the
compressor disclosed in the above publication includes a cooling
passageway for the armature. The cooling passageway guides the
refrigerant to the armature before the refrigerant is returned to
the scroll unit. Since the temperature of the return refrigerant is
considerably lower than the ambient temperature, the armature can
be effectively cooled by the return refrigerant.
[0005] Specifically, the cooling passageway includes an air gap
between the rotor and stator of the armature, a gap between the
stator and the inner peripheral wall of the common housing, and
gaps between stator coils. These gaps are, however, so narrow that
the cooling passageway constitutes a large resistance to the flow
of the refrigerant flowing toward the scroll unit, increasing the
pressure loss of the refrigerant. Consequently, the scroll unit is
unable to efficiently suck in the return refrigerant, so that the
suction efficiency of the scroll unit lowers.
[0006] To eliminate the inconvenience, a motor disclosed in
Unexamined Japanese Patent Publication No. 2002-165406 has an
armature provided with an axial passage extending through the rotor
as well as with fans attached to the respective opposite end faces
of the rotor. As the fans rotate, the refrigerant is forced to flow
through the axial passage in one direction, thus cooling the
armature.
[0007] Where the armature disclosed in the above publication is
applied to a scroll compressor, however, the size of the armature
increases by an amount corresponding to the axial passage formed
through the rotor, which entails increase in the outside diameter
and weight of the common housing of the scroll compressor. Further,
the use of the fans leads to an increased number of component parts
of the armature, increasing the cost of the scroll compressor.
DISCLOSURE OF THE INVENTION
[0008] An object of the present invention is to provide a scroll
fluid machine capable of enhancing the suction efficiency of a
scroll unit thereof without entailing increase in size or in the
number of component parts.
[0009] To achieve the object, the present invention provides a
scroll fluid machine comprising: a housing; a scroll unit contained
in the housing, the scroll unit having a fixed scroll and a movable
scroll cooperating with each other to compress a working fluid; an
armature contained in the housing adjacently to the scroll unit and
including a rotor for revolving the movable scroll, the rotor
having a peripheral surface and opposite end faces; and a fluid
conduit located inside the housing to guide the working fluid
toward the scroll unit through the armature and including a helical
groove formed in the peripheral surface of the rotor, the helical
groove having opposite ends opening in the respective opposite end
faces of the rotor.
[0010] In the scroll fluid machine constructed as above, as the
scroll unit is driven by the armature, the working fluid guided
through the fluid conduit is sucked into the scroll unit. The
pressure of the working fluid thus sucked in changes while the
working fluid passes through the scroll unit, and then the working
fluid is discharged from the scroll unit.
[0011] The fluid conduit includes the helical groove formed on the
rotor, and thus, a major part of the working fluid supplied to the
scroll unit flows through the helical groove. The helical groove
increases the cross-sectional area of the fluid conduit, and
therefore, the fluid conduit does not constitute a large resistance
to the flow of the working fluid flowing toward the scroll unit. As
a result, the pressure loss of the working fluid is reduced and the
working fluid suction efficiency of the scroll unit improves.
[0012] Preferably, the helical groove has a helix direction such
that when the rotor is rotated, the working fluid in the helical
groove is forced toward the scroll unit. In this case, while the
rotor is rotating, the working fluid in the helical groove is
constantly forced toward the scroll unit. Accordingly, the working
fluid is forced to flow through the helical groove toward the
scroll unit, thus making it possible not only to further reduce the
pressure loss of the working fluid but to further enhance the
suction efficiency of the scroll unit.
[0013] Specifically, the scroll unit is a compression unit for a
refrigeration circuit, and the fluid conduit guides a refrigerant
to be returned to the compression unit. Preferably, in this case,
the peripheral surface of the rotor having the helical groove
formed therein is an outer peripheral surface of the rotor.
[0014] The temperature of the refrigerant being returned to the
compression unit is considerably lower than the ambient
temperature, and therefore, when the refrigerant flows through the
helical groove of the rotor, the armature is effectively cooled by
the refrigerant. Consequently, the armature is prevented from being
overheated, whereby the performance of the armature is
maintained.
[0015] The rotor may have a laminated structure obtained by
laminating ring-shaped magnetic steel sheets one upon another in an
axial direction of the rotor, and each magnetic steel sheet may
have a helical groove-forming notch cut in a peripheral edge
thereof constituting the peripheral surface of the rotor. In this
case, the helical groove can be easily formed in the peripheral
surface of the rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a sectional view of a scroll compressor as a fluid
machine.
[0017] FIG. 2 is a perspective view of a rotor appearing in FIG.
1.
[0018] FIG. 3 is a front view of a magnetic steel sheet
constituting the rotor of FIG. 2.
BEST MODE OF CARRYING OUT THE INVENTION
[0019] A scroll compressor shown in FIG. 1 is used in an automotive
air-conditioning system, that is, in a refrigeration circuit. The
compressor has a cylindrical housing 10. The housing 10 has a unit
casing 12, a motor casing 14, and a circuit casing 16 arranged in
this order as viewed from left to right in FIG. 1. The unit casing
12 and the motor casing 14 are coupled together by a plurality of
connecting bolts 18, and the motor casing 14 and the circuit casing
16 are also coupled together by a plurality of connecting bolts
19.
[0020] The unit casing 12 contains a scroll unit 20 having a fixed
scroll 22 and a movable scroll 24. The fixed scroll 22 is abutted
against an end wall 12a of the unit casing 12 and fixed to the end
wall 12a by fixing bolts 26. The movable scroll 24 is located close
to the motor casing 14.
[0021] The fixed and movable scrolls 22 and 24 have respective
spiral walls 22f and 24m engaged with each other. The spiral walls
22f and 24m thus engaged with each other define a plurality of
compression chambers 28 therebetween. As the movable scroll 24
revolves about the fixed scroll 22, the compression chambers 28
spirally move in the circumferential direction toward the center of
the fixed scroll 22, and in the process of movement, the capacities
of the compression chambers 28 decrease by degrees.
[0022] The unit casing 12 has a discharge chamber 30 defined
therein. The discharge chamber 30 has its end walls constituted by
the end wall 12a of the unit casing 12 and an end plate 22a of the
fixed scroll 22, respectively. The end plate 22a has a discharge
hole 32 formed through the center thereof. The discharge hole 32 is
opened and closed by a discharge valve (not shown). The discharge
valve is arranged inside the discharge chamber 30 and fixed to the
end plate 22a of the fixed scroll 22.
[0023] Further, the unit casing 12 has a discharge port 34 formed
in its end wall 12a. The discharge port 34 has an inner end
communicating with the discharge chamber 30 and has an outer end
connected to a refrigerant circulation path (not shown) of the
refrigeration circuit, or more specifically, to a condenser (not
shown) of the refrigeration circuit through the refrigerant
circulation path.
[0024] The movable scroll 24 is allowed to revolve but is prevented
from rotating on its axis. More specifically, a ball coupling 36 is
interposed between an end plate 24a of the movable scroll 24 and
one end of the motor casing 14. The ball coupling 36 prevents the
movable scroll 24 from rotating on its axis and at the same time
transmits the thrust load of the movable scroll 24 to the motor
casing 14.
[0025] On the other hand, the motor casing 14 contains an armature
38. The armature 38 partitions the interior of the motor casing 14
into a chamber 13 close to the unit casing 12 and a chamber 15
close to the circuit casing 16. Also, the armature 38 has a rotary
shaft 40 located at the center of the motor casing 14 and extending
from the one end of the motor casing 14 to the circuit casing 16.
The rotary shaft 40 is rotatably supported at opposite ends by the
one end of the motor casing 14 and a partition wall 16a of the
circuit casing 16 through a ball bearing 42 and a roller bearing
44, respectively. The partition wall 16a partitions the interior of
the circuit casing 16 into a chamber 17 communicating with the
interior of the motor casing 14 and a circuit chamber 19 separated
from the chamber 17.
[0026] As is clear from FIG. 1, the rotary shaft 40 has a
large-diameter portion 46 formed at one end thereof. The
large-diameter end portion 46 has an end face facing the end plate
of the movable scroll 24. A crankpin 48 protrudes from the end face
of the large-diameter end portion 46 toward the movable scroll 24,
and an eccentric bushing 50 is fitted on the crankpin 48. The
eccentric bushing 50 is rotatably supported by a boss 24a of the
movable scroll 24 through a needle bearing 52.
[0027] When the rotary shaft 40 is rotated, the rotational force
thereof is transmitted through the crankpin 48, the eccentric
bushing 50 and the needle bearing 52 to the movable scroll 24.
Consequently, the movable scroll 24 revolves about the fixed scroll
22 while being prevented from rotating on its axis by the ball
coupling 36. The revolving radius of the movable scroll 24 is
determined by the distance between the axis of the rotary shaft 40
and the axis of the crankpin 48.
[0028] The armature 38 has a rotor 54 mounted on the rotary shaft
40. The rotor 54 is surrounded by a stator 56 fixed to the inner
peripheral wall of the motor casing 14.
[0029] On the other hand, the circuit casing 16 has a return port
58 formed in its outer peripheral wall. The return port 58 has an
inner end communicating with the interior of the motor casing 14,
that is, the chamber 15, through the chamber 17 of the circuit
casing 16. The other end of the return port 58 is connected to the
refrigerant circulation path of the refrigeration circuit, or more
specifically, to an evaporator of the refrigeration circuit through
the refrigerant circulation path. Accordingly, the return
refrigerant delivered from the evaporator flows through the return
port 58 into the chamber 17 in the circuit casing 16 and then is
supplied from the chamber 17 to the interior of the motor casing
14.
[0030] A driver circuit 59 for the armature 38 is arranged in the
circuit chamber 19 of the circuit casing 16. The driver circuit 59
controls the supply of electric power to the armature 38 and thus
the rotation of the armature 38.
[0031] A cooling conduit is provided in the motor casing 14 and
serves to guide the return refrigerant supplied to the motor casing
14 through the armature 38. Specifically, the cooling conduit
includes a helical groove as its principal part, besides an air gap
Ga between the rotor 54 and the stator 56, a gap Gb between the
inner peripheral wall of the motor casing 14 and the outer
peripheral wall of the stator 56, and gaps (not shown) between
stator coils. These gaps and the helical groove interconnect the
chambers 13 and 15 located on the opposite sides of the armature
38.
[0032] The helical groove will be now described in detail. As is
clear from FIG. 1, the rotor 54 has a laminated structure obtained
by laminating numerous ring-shaped magnetic steel sheets 62 one
upon another in the axial direction of the rotary shaft 40. The
helical groove 64, shown in FIG. 2, is formed in the outer
peripheral surface of the rotor 54 and has opposite ends opening in
the respective opposite end faces of the rotor 54. More
specifically, the helical groove 64 has a helix direction similar
to that of a right-handed screw such that when the rotor 54 is
rotated, the groove makes motion advancing toward the unit casing
12.
[0033] In the rotor 54 of this embodiment, each magnetic steel
sheet 62 has a U-shaped notch 66 cut in an outer peripheral surface
thereof. When the rotor 54 is formed using a large number of such
magnetic steel sheets 62, the magnetic steel sheets 62 are
laminated one upon the other such that the notches 66 of adjacent
magnetic steel sheets are slightly shifted in the circumferential
direction of the rotor 54, whereby the helical groove 64 is formed
by the notches 66 contiguous with each other in the axial direction
of the rotor 54.
[0034] Alternatively, the helical groove 64 may be formed by
mechanically machining the outer peripheral surface of the rotor 54
after the rotor 54 is prepared by laminating a large number of
magnetic steel sheets 62.
[0035] On the other hand, the unit casing 12 has a suction chamber
60 for the scroll unit 20 defined therein. The suction chamber 60
surrounds the movable scroll 24 of the scroll unit 20 and is
separated from the aforementioned discharge chamber 30 by the fixed
scroll 22. The suction chamber 60 is connected with the chamber 13
in the motor casing 14 through the internal space of the ball
coupling 36, the space between the movable scroll 24 and the ball
bearing 42, and the internal space of the ball bearing 42.
Accordingly, the suction chamber 60 is connected with the return
port 58 of the circuit casing 16 through a refrigerant conduit
including the aforementioned cooling conduit, whereby the return
refrigerant flowing into the return port 58 is supplied to the
suction chamber 60 through the refrigerant conduit.
[0036] When the rotary shaft 40 of the armature 38 is rotated, the
rotation thereof is transmitted to the movable scroll 24 through
the crankpin 48 and the eccentric bushing 50. Consequently, the
movable scroll 24 revolves about the fixed scroll 22 while being
prevented from rotating on its axis. As the movable scroll 24
revolves, one compression chamber 28 opens into the suction chamber
60 to be supplied with the refrigerant and is then shut off from
the suction chamber 60.
[0037] The compression chamber 28 thereafter moves toward the
discharge hole 32 of the fixed scroll 22 as the movable scroll 24
further revolves, and since the capacity of the compression chamber
28 decreases in the process of revolution, the refrigerant sucked
in the compression chamber 28 is compressed. The compression
chamber 28 then reaches the discharge hole 32, and when the
refrigerant pressure in the compression chamber 28 surpasses the
valve closing pressure of the discharge valve, the discharge valve
opens, whereupon the compressed refrigerant in the compression
chamber 28 is discharged to the discharge chamber 30 through the
discharge hole 32.
[0038] The compressed refrigerant in the discharge chamber 30 is
delivered through the discharge port 34 to the refrigerant
circulation path and supplied to the condenser of the refrigeration
circuit. Subsequently, the compressed refrigerant is supplied via a
receiver and an expansion valve in the refrigerant circulation path
to the evaporator, which returns the refrigerant to the return port
58. The refrigerant thus returned to the return port 58 flows into
the chamber 17 in the circuit casing 16 and then is supplied to the
suction chamber 60 through the aforementioned refrigerant conduit,
namely, the cooling conduit.
[0039] The temperature of the return refrigerant is considerably
lower than the ambient temperature, as stated above, and therefore,
the return refrigerant effectively cools the armature 38 while
passing through the cooling conduit, thus preventing the armature
38 from becoming overheated.
[0040] The cooling conduit includes the helical groove 64 as its
principal part and the helical groove 64 serves to increase the
effective cross-sectional flow area of the cooling conduit as a
whole. Consequently, the cooling conduit does not constitute a
large resistance to the flow of the return refrigerant flowing
toward the suction chamber 60, so that the pressure loss of the
return refrigerant is small.
[0041] Further, since the helical groove 64 rotates together with
the rotor 54, the return refrigerant in the helical groove 64 is
forced to move toward the unit casing 12, thus producing a flow of
the return refrigerant in the helical groove 64 directed from the
chamber 15 to the chamber 13 of the motor casing 14.
[0042] As a result, not only the armature 38 is effectively cooled
by the forced flow of the return refrigerant but also the suction
chamber 60 is supplied with an increased amount of the return
refrigerant. Accordingly, the suction efficiency of the scroll unit
20 is enhanced, making it possible to improve the performance of
the scroll compressor.
[0043] The helical groove 64 does not entail increase in the
diameter of the rotor 54 or in the number of component parts of the
armature 38, so that the scroll compressor need not be increased in
size. Furthermore, the weight of the scroll compressor can be
reduced.
[0044] The present invention is not limited to the foregoing
embodiment and may be modified in various ways.
[0045] For example, as indicated by the dot-dot-dash lines in FIG.
3, the rotor 54 may have a plurality of helical grooves 64 formed
in the outer peripheral surface thereof. Also, one or more helical
grooves 64 may be formed in the inner peripheral surface of the
rotor, instead of the outer peripheral surface of same.
[0046] Further, the present invention is equally applicable to a
scroll expander, besides the compressor.
* * * * *