U.S. patent application number 15/875220 was filed with the patent office on 2018-09-06 for housing for turbocharger and method for manufacturing the same.
This patent application is currently assigned to OTICS CORPORATION. The applicant listed for this patent is OTICS CORPORATION. Invention is credited to Tomoyuki ISOGAI.
Application Number | 20180252229 15/875220 |
Document ID | / |
Family ID | 63355027 |
Filed Date | 2018-09-06 |
United States Patent
Application |
20180252229 |
Kind Code |
A1 |
ISOGAI; Tomoyuki |
September 6, 2018 |
HOUSING FOR TURBOCHARGER AND METHOD FOR MANUFACTURING THE SAME
Abstract
A housing for a turbocharger is dividedly formed of at least a
scroll piece and a shroud piece, including a refrigerant flow path
for cooling a diffuser surface. The refrigerant flow path is
composed of an annular space defined by a first flow-path formation
part of the scroll piece and a second flow-path formation part of
the shroud piece, which are formed respectively in each opposing
part of the scroll piece and the shroud piece facing each other.
The first and second flow path formation parts are in contact with
each other to form a contact portion at the outermost periphery of
an inside surface of the refrigerant flow path. The contact portion
has a groove formed by recessing the inside surface of the
refrigerant flow path outwardly in the radial direction
continuously in the circumferential direction. The groove is filled
with a sealing material for sealing the contact portion.
Inventors: |
ISOGAI; Tomoyuki; (Aichi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OTICS CORPORATION |
Nishio-city |
|
JP |
|
|
Assignee: |
OTICS CORPORATION
Nishio-city
JP
|
Family ID: |
63355027 |
Appl. No.: |
15/875220 |
Filed: |
January 19, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/441 20130101;
F04D 29/582 20130101; F04D 29/624 20130101; F04D 17/10 20130101;
F04D 29/4206 20130101; F04D 29/083 20130101 |
International
Class: |
F04D 29/08 20060101
F04D029/08; F04D 29/44 20060101 F04D029/44; F04D 29/58 20060101
F04D029/58 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2017 |
JP |
2017-039606 |
Claims
1. A housing for a turbocharger in which a compressor impeller is
housed, the housing comprising: a shroud part that surrounds the
compressor impeller in a circumferential direction and has a shroud
surface facing the compressor impeller; a diffuser part that is
formed on an outer peripheral side of the compressor impeller in
the circumferential direction and forms a diffuser passage, the
diffuser passage allowing compressed air discharged from the
compressor impeller to pass therethrough; a scroll chamber
formation part that forms a scroll chamber for guiding the
compressed air passing through the diffuser passage to an outside;
and a refrigerant flow path that is formed along the diffuser part
in the circumferential direction, and allows a refrigerant for
cooling the diffuser part to pass therethrough, wherein the housing
is composed of a scroll piece including at least part of the scroll
chamber formation part, and a shroud piece including at least part
of the scroll chamber formation part, the diffuser part, and the
shroud part and being inserted in an inner side of the scroll
piece, the refrigerant flow path is composed of an annular space
that is defined by a first flow-path formation part of the scroll
piece and a second flow-path formation part of the shroud piece,
the first flow-path formation part and the second flow-path
formation part being formed respectively in each opposing part of
the scroll piece and the shroud piece which face each other, the
first flow path formation part and the second flow path formation
part are brought into contact with each other to form a contact
portion at a position corresponding to an outermost periphery of an
inside surface of the refrigerant flow path, the contact portion
has a groove that is formed by recessing the inside surface of the
refrigerant flow path outwardly in a radial direction and is
continuous in a circumferential direction, and the groove is filled
with a sealing material for sealing the contact portion.
2. The housing for a turbocharger according to claim 1, wherein the
groove is formed such that an imaginary circle centered on a shaft
center of the compressor impeller is positioned inside of the
groove.
3. The housing for a turbocharger according to claim 1, wherein the
groove has a shape notched into a V shape outwardly in the radial
direction such that a deepest position of the groove in a cross
section including the shaft center of the compressor impeller is
positioned on a boundary between the first flow path formation part
and the second flow path formation part.
4. The housing for a turbocharger according to claim 2, wherein the
groove has a shape notched into a V shape outwardly in the radial
direction such that a deepest position of the groove in a cross
section including the shaft center of the compressor impeller is
positioned on a boundary between the first flow path formation part
and the second flow path formation part.
5. The housing for a turbocharger according to claim 1, wherein the
sealing material is provided between the scroll piece and the
shroud piece at the contact portion, and seals a space between the
scroll piece and the shroud piece.
6. The housing for a turbocharger according to claim 2, wherein the
sealing material is provided between the scroll piece and the
shroud piece at the contact portion, and seals a space between the
scroll piece and the shroud piece.
7. The housing for a turbocharger according to claim 3, wherein the
sealing material is provided between the scroll piece and the
shroud piece at the contact portion, and seals a space between the
scroll piece and the shroud piece.
8. The housing for a turbocharger according to claim 4, wherein the
sealing material is provided between the scroll piece and the
shroud piece at the contact portion, and seals a space between the
scroll piece and the shroud piece.
9. The housing for a turbocharger according to claim 1, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
10. The housing for a turbocharger according to claim 2, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
11. The housing for a turbocharger according to claim 3, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
12. The housing for a turbocharger according to claim 4, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
13. The housing for a turbocharger according to claim 5, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
14. The housing for a turbocharger according to claim 6, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
15. The housing for a turbocharger according to claim 7, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
16. The housing for a turbocharger according to claim 8, wherein a
contact surface of the scroll piece and a contact surface of the
shroud piece at the contact portion are parallel to a surface
perpendicular to a shaft direction.
17. A method for manufacturing the housing for a turbocharger
according to claim 1, the method comprising: a preparation step of
preparing the scroll piece and the shroud piece; an assembling step
of assembling the shroud piece to the scroll piece by
press-fitting, and bringing the first flow-path formation part into
contact with the second flow-path formation part, thereby forming
the refrigerant flow path composed of the annular space; a
providing step of providing a sealing material having a fluidity by
feeding the sealing material to the refrigerant flow path after the
assembling step, or by applying the sealing material to at least
one of the first flow-path formation part and the second flow-path
formation part prior to the assembling step; a filling step of
filling the groove with the sealing material by rotating the scroll
piece and the shroud piece around the shaft center of the
compressor impeller; and a curing step of curing the sealing
material filling the groove.
18. A method for manufacturing the housing for a turbocharger
according to claim 16, the method comprising: a preparation step of
preparing the scroll piece and the shroud piece; an assembling step
of assembling the shroud piece to the scroll piece by
press-fitting, and bringing the first flow-path formation part into
contact with the second flow-path formation part, thereby forming
the refrigerant flow path composed of the annular space; a
providing step of providing a sealing material having a fluidity by
feeding the sealing material to the refrigerant flow path after the
assembling step, or by applying the sealing material to at least
one of the first flow-path formation part and the second flow-path
formation part prior to the assembling step; a filling step of
filling the groove with the sealing material by rotating the scroll
piece and the shroud piece around the shaft center of the
compressor impeller; and a curing step of curing the sealing
material filling the groove.
19. The method for manufacturing the housing for a turbocharger
according to claim 17, wherein lathe machining for forming the
shroud surface is performed in the filling step simultaneously with
filling the groove with the sealing material.
20. The method for manufacturing the housing for a turbocharger
according to claim 18, wherein lathe machining for forming the
shroud surface is performed in the filling step simultaneously with
filling the groove with the sealing material.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority under 35 U.S.C.
.sctn. 119 to Japanese Application No. 2017-039606, filed on Mar.
2, 2017, entitled "HOUSING FOR TURBOCHARGER AND METHOD FOR
MANUFACTURING THE SAME". The contents of this application are
incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a housing for a
turbocharger and a method for manufacturing the same.
Description of the Related Art
[0003] A turbocharger to be mounted on an internal combustion
engine of an automobile or the like includes a compressor impeller
and a turbine impeller, which are housed in a housing. The
compressor impeller is disposed in an air flow path that is formed
inside of the housing. The air flow path is provided with an intake
port for sucking in air toward the compressor impeller, a diffuser
passage through which compressed air discharged from the compressor
impeller passes through, and a discharge scroll chamber into which
the compressed air passing through the diffuser passage flows. The
discharge scroll chamber discharges the compressed air into the
internal combustion engine side.
[0004] The internal combustion engine of an automobile or the like
is, in some cases, provided with a positive crankcase ventilation
system (hereinafter referred to as PCV) for purifying the inside of
a crankcase and/or a head cover by reflowing a blowby gas (mainly
composed of unburned gas) that has generated in the crankcase. In
this case, oil (oil mist) may flow out from the PCV into an intake
passage that is positioned upstream of the compressor in the
turbocharger.
[0005] At that time, if air pressure at the outlet port of the
compressor is high, air temperature at the outlet port of the
compressor is made high, so that the oil flowing out from the PCV
is concentrated and thickened by evaporation to have high
viscosity. In some cases, the oil is accumulated as deposit on, for
example, a diffuser surface of the housing for a turbocharger
and/or the surface of a bearing housing which opposes the diffuser
surface. And, there is a risk that the accumulated deposit may
narrow the diffuser passage to thereby cause reduction in
performance of the turbocharger and reduction in output of the
internal combustion engine.
[0006] In the conventional technique to prevent such deposit
accumulation in the diffuser passage as described above, the air
temperature at the outlet port of the compressor was controlled to
some extent. As a result, a turbocharger was not able to
satisfactorily exhibit its performance, and the output of an
internal combustion engine was not satisfactorily raised.
[0007] Patent Document 1 discloses a configuration to prevent
deposit accumulation in a diffuser passage, in which a refrigerant
flow path is provided inside of a housing for a turbocharger to
allow a refrigerant to pass therethrough, thereby inhibiting an
increase in the temperature of compressed air passing through an
air flow path inside of the housing. In the configuration disclosed
in Patent Document 1, the housing for a turbocharger is composed of
a first piece, a second piece and a third piece, and these
components are assembled to each other to define the refrigerant
flow path.
PRIOR ART LITERATURE
[0008] Patent Document
[0009] Patent Document 1
[0010] JP-A-2016-176353
[0011] In the configuration disclosed in Patent Document 1,
however, it is necessary to form a holding portion for holding an
O-ring serving as a sealing member between the first piece and the
second piece and to fit the sealing member into the holding
portion, and in addition, to hold the sealing member by the first
piece and the second piece. Thus, parts count is indispensably
increased, which causes increase in manufacturing cost and
reduction in assembling workability.
[0012] Further, in the configuration disclosed in Patent Document
1, each piece is formed in a shape having no undercut, employing
dies-cutting which enables each piece to be molded by die casting.
Because the cross-sectional shape of the scroll chamber largely
differs from a circle accordingly, reduction in compression
efficiency of supplied air cannot be avoided.
[0013] As a method to form the refrigerant flow path in the housing
for a turbocharger, it is conceivable to use gravity casting with a
sand core. According to this method, high flexibility in shape can
be expected to thereby address complicated shapes. On the other
hand, this method requires long casting cycle, and the method needs
a sand shakeout operation for removing the sand core and an
inspection work for checking remaining casting sand. Therefore, the
number of manufacturing processes is increased, and the
productivity is reduced accordingly. In addition, there is a risk
that the refrigerant flow path may communicate with outside due to
a cavity defect and may have a leak of the refrigerant to the
outside.
[0014] The present invention has been made in view of this
background, and it is intended to provide a housing for a
turbocharger which can be prevented from having deposit
accumulation, while exhibiting an excellent assembling workability
and having a capability of being easily formed by die casting.
SUMMARY OF THE INVENTION
[0015] One aspect of the present invention provides a housing for a
turbocharger in which a compressor impeller is housed, the housing
including:
[0016] a shroud part that surrounds the compressor impeller in a
circumferential direction and has a shroud surface facing the
compressor impeller;
[0017] a diffuser part that is formed on an outer peripheral side
of the compressor impeller in the circumferential direction and
forms a diffuser passage, the diffuser passage allowing compressed
air to pass therethrough;
[0018] a scroll chamber formation part that forms a scroll chamber
for guiding the compressed air passing through the diffuser passage
to an outside; and
[0019] a refrigerant flow path that is formed along the diffuser
part in the circumferential direction, and allows a refrigerant for
cooling the diffuser part to pass therethrough, wherein
[0020] the housing is composed of a scroll piece including at least
part of the scroll chamber formation part, and a shroud piece
including at least part of the scroll chamber formation part, the
diffuser part, and the shroud part and being inserted in an inner
side of the scroll piece,
[0021] the refrigerant flow path is composed of an annular space
that is defined by a first flow-path formation part of the scroll
piece and a second flow-path formation part of the shroud piece,
the first flow-path formation part and the second flow-path
formation part being formed respectively in each opposing part of
the scroll piece and the shroud piece which face each other,
[0022] the first flow path formation part and the second flow path
formation part are brought into contact with each other to form a
contact portion at a position corresponding to an outermost
periphery of an inside surface of the refrigerant flow path,
[0023] the contact portion has a groove that is formed by recessing
the inside surface of the refrigerant flow path outwardly in a
radial direction and is continuous in a circumferential direction,
and
[0024] the groove is filled with a sealing material for sealing the
contact portion.
[0025] According to the aforementioned aspect, the housing for a
turbocharger is dividedly formed, and the refrigerant flow path is
defined by the first flow-path formation part of the scroll piece
and the second flow-path formation part of the shroud piece, both
of which are formed respectively in each opposing part of the
scroll piece and the shroud piece facing each other. At the
position corresponding to the outermost periphery of the inside
surface of the refrigerant flow path, the first flow path formation
part and the second flow path formation part are brought into
contact with each other to form the contact portion. The contact
portion has the groove that is formed by recessing the inside
surface of the refrigerant flow path outwardly in the radial
direction and is continuous in the circumferential direction. The
groove is filled with a sealing material for sealing the contact
portion. In such a configuration, a space between the first flow
path formation part and the second flow path formation part, which
forms the flow path, can be sealed only by filling the groove with
the sealing material. Consequently, it is not necessary to
interpose an O-ring between the first flow path formation part and
the second flow path formation part, and the assembling workability
is satisfactory. Further, because the O-ring itself is not
necessary, reduction of the parts count can be achieved.
[0026] Further, the housing for a turbocharger is dividedly formed
and includes the scroll piece and the shroud piece. The scroll
chamber is formed by assembling at least both pieces to each other.
Thus, the scroll chamber can be formed to have a circular cross
section, and the scroll chamber formation part can be formed into a
shape having no undercut, which can be formed by die-cutting. As a
result, the scroll chamber can be more readily formed by die
casting, and the compression efficiency of the supplied air can be
improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a cross-sectional view of a housing for a
turbocharger according to Embodiment 1.
[0028] FIG. 2 is a sectional view taken along arrows II-II in FIG.
1.
[0029] FIG. 3 is a partially enlarged view of the cross sectional
view of the housing for a turbocharger according to Embodiment
1.
[0030] FIG. 4 is a flow chart showing a method for manufacturing
the turbocharger according to Embodiment 1.
[0031] FIG. 5 is a schematic diagram for illustrating the method
for manufacturing the turbocharger according to Embodiment 1.
[0032] FIG. 6 is another schematic diagram for illustrating the
method for manufacturing the turbocharger according to Embodiment
1.
[0033] FIG. 7 is further another schematic diagram for illustrating
the method for manufacturing the turbocharger according to
Embodiment 1.
DETAILED DESCRIPTION OF THE INVENTION
[0034] "Circumferential direction" in the present specification
means the rotation direction of a compressor impeller, "shaft
direction" means the direction of the rotation shaft of the
compressor impeller, "radial direction" means the radius direction
of an imaginary circle centered on the shaft center of the
compressor impeller, and "outwardly in the radial direction" is
defined to be in the direction straightly extending from the center
of the imaginary circle to the circumference of the circle.
[0035] The groove is preferably formed such that an imaginary
circle centered on a shaft center of the compressor impeller is
positioned inside of the groove. In such a configuration, it
becomes easy to fill the groove uniformly with the sealing material
utilizing a centrifugal force generated by rotation around the
shaft center of the compressor impeller, which further improves
assembling workability.
[0036] The groove preferably has a shape notched into a V shape
outwardly in the radial direction such that the deepest position of
the groove in the cross section including the shaft center of the
compressor impeller is positioned on the boundary between the first
flow path formation part and the second flow path formation part.
In such a configuration, the sealing material filling the groove is
easily held in the groove, and easily enters into a space between
the first flow path formation part and the second flow path
formation part at the contact portion. Consequently, the
sealability between the first flow path formation part and the
second flow path formation part can be further enhanced.
[0037] The sealing material is preferably provided between the
scroll piece and the shroud piece at the contact portion and seals
a space between the scroll piece and the shroud piece. In such a
configuration, the sealability between the scroll piece and the
shroud piece can be further improved.
[0038] At the contact portion, a contact surface of the scroll
piece and a contact surface of the shroud piece are preferably
parallel to a surface perpendicular to the shaft direction. In such
a configuration, the sealing material filling the groove easily
enters into a space between the first flow path formation part and
the second flow path formation part at the contact portion
utilizing the centrifugal force generated by rotation around the
shaft center of the compressor impeller. Consequently, the
sealability between the first flow path formation part and the
second flow path formation part can be further improved.
[0039] As a method for manufacturing the aforementioned housing for
a turbocharger, it is preferable to utilize a method for
manufacturing the housing for a turbocharger including:
[0040] a preparation step of preparing the scroll piece and the
shroud piece;
[0041] an assembling step of assembling the shroud piece to the
scroll piece by press-fitting, and bringing the first flow-path
formation part into contact with the second flow-path formation
part, thereby forming the refrigerant flow path composed of the
annular space;
[0042] a providing step of providing a sealing material having a
fluidity by feeding the sealing material to the refrigerant flow
path after the assembling step, or by applying the sealing material
to at least one of the first flow-path formation part and the
second flow-path formation part prior to the assembling step;
[0043] a filling step of filling the groove with the sealing
material by rotating the scroll piece and the shroud piece around
the shaft center of the compressor impeller; and
[0044] a curing step of curing the sealing material filling the
groove.
[0045] Lathe machining for forming the shroud surface is preferably
performed in the filling step simultaneously with filling the
groove with the sealing material. In such a configuration, the
groove can be filled with the sealing material simultaneously with
formation of the shroud surface, so that the manufacturing process
can be simplified.
EMBODIMENT
Embodiment 1
[0046] Hereinafter, an embodiment of the aforementioned housing for
a turbocharger will be described.
[0047] As shown in FIG. 1, a housing 1 for a turbocharger houses a
compressor impeller 13, and is provided with an intake port 11, a
shroud part 20, a diffuser part 30, a scroll chamber formation part
120 and a refrigerant flow path 5. The shroud part 20 surrounds the
compressor impeller 13 in the circumferential direction and has a
shroud surface 22 facing the compressor impeller 13.
[0048] The diffuser part 30 is formed on the outer peripheral side
of the compressor impeller 13 in the circumferential direction and
forms a diffuser passage 15 that allows compressed air discharged
from the compressor impeller 13 to pass therethrough.
[0049] The scroll chamber formation part 120 forms a scroll chamber
12 for guiding the compressed air passing through the diffuser
passage 15 to the outside.
[0050] The refrigerant flow path 5 is formed along the diffuser
part 30 in the circumferential direction, and allows a refrigerant
for cooling the diffuser part 30 to pass therethrough.
[0051] The housing 1 is composed of a scroll piece 2 including at
least part of the scroll chamber formation part 120, and a shroud
piece 3 including at least part of the scroll chamber formation
part 120, the diffuser part 30, and the shroud part 20 and being
inserted in the inner side of the scroll piece 2.
[0052] The refrigerant flow path 5 is composed of an annular space
50 that is defined by a first flow-path formation part 51 of the
scroll piece 2 and a second flow-path formation part 52 of the
shroud piece 3, the first flow-path formation part 51 and the
second flow-path formation part 52 being formed respectively in
each opposing part of the scroll piece 2 and the shroud piece 3
which face each other.
[0053] The first flow path formation part 51 and the second flow
path formation part 52 are brought into contact with each other to
form a contact portion 53 at a position corresponding to the
outermost periphery of an inside surface 54 of the refrigerant flow
path 5.
[0054] The contact portion 53 has a groove 55 that is formed by
recessing the inside surface 54 of the refrigerant flow path 5
outwardly in the radial direction and is continuous in the
circumferential direction.
[0055] The groove 55 is filled with a sealing material 56 for
sealing the contact portion 53 as shown in FIG. 3.
[0056] Hereinafter, the housing 1 for a turbocharger will be
described in detail.
[0057] As shown in FIG. 1, the housing 1 for a turbocharger is
formed by assembling the scroll piece 2, the shroud piece 3, and an
outer periphery piece 4 in the shaft direction Y, each of which has
been manufactured as a separate member.
[0058] As shown in FIGS. 1 and 2, the scroll piece 2 includes the
intake port 11, a first scroll chamber formation part 121, an outer
peripheral portion 125, and the first flow-path formation part 51.
The intake port 11 is defined by an intake port formation part 110
that has a cylindrical shape penetratingly formed in the shaft
direction Y. The first scroll chamber formation part 121 forms a
wall surface of the scroll chamber 12 on the intake side Y1. The
outer peripheral portion 125 corresponds to a part of the first
scroll chamber formation part 121 on the side Y2 opposite to the
intake side Y1, and forms the outer peripheral portion of the
housing 1 for a turbocharger. The outer peripheral portion 125 is
provided with the outer peripheral portion 4. The outer peripheral
portion 4 is annular, and includes an insertion part 41 to be
press-fitted into the outer peripheral portion 125 and a third
scroll chamber formation part 123 constituting the wall surface of
the scroll chamber 12 on the outer peripheral side.
[0059] As shown in FIG. 1, the first flow-path formation part 51 of
the scroll piece 2 is configured to form the refrigerant flow path
5 with the second flow-path formation part 52 to be described
later, and is provided on the Y2 side of the intake port formation
part 110. As shown in FIG. 3, the first flow-path formation part 51
has a first wall surface 511 corresponding to the wall surface of
the refrigerant flow path 5 on the intake side Y1. In this
embodiment, the first wall surface 511 is made gradually inclined
so as to approach the Y2 side opposite to the intake side Y1 as the
first wall surface 511 goes outward in the radial direction. The
first flow-path formation part 51 has a first contact surface 531,
which is parallel to the radial direction, at the radially outside
end part of the first wall surface 511. The first contact surface
531 is in contact with a second contact surface 532 of the shroud
piece 3, which will be described later. The first flow-path
formation part 51 is provided with a penetration hole 513
penetrating from the first wall surface 511 to the surface opposite
to the first wall surface 511. Although not shown in any figure,
the penetration hole 513 is provided in two locations.
[0060] The shroud piece 3 includes a shroud press-fit portion 31, a
second scroll chamber formation part 122, the shroud part 20, the
diffuser part 30, and the second flow-path formation part 52, as
shown in FIG. 1. The shroud press-fit portion 31 is formed in a
cylindrical shape, and is press-fitted into the intake port 11. The
second scroll chamber formation part 122 forms an inner-periphery
side wall surface of the scroll chamber 12. The shroud part 20
forms a shroud surface 22 that faces the compressor impeller 13.
The diffuser part 30 forms a diffuser surface 34 that extends from
the shroud surface 22 to the scroll chamber 12. The diffuser
surface 34 faces a facing surface formed in a seal plate of a
bearing housing that is not shown in any figure, leaving a
predetermined space to form the diffuser passage 15 with the
opposing surface.
[0061] As shown in FIG. 1, the second flow-path formation part 52
is configured to form the refrigerant flow path 5 with the
aforementioned first flow-path formation part 51, and is formed in
the diffuser part 30 on the intake side Y1 radially outside of the
shroud part 20. As shown in FIG. 3, the second flow-path formation
part 52 includes a second wall surface 521 corresponding to the
wall surface of the refrigerant flow path 5 on the Y2 side. In this
embodiment, the second wall surface 521 is recessively formed
toward the Y2 side, and has a U-shape in the cross section parallel
to the shaft direction. At the same time, the second wall surface
521 forms an annular recess extending in the circumferential
direction radially outside of the shroud surface 22 as shown in
FIG. 2. As shown in FIG. 3, the second flow-path formation part 52
has the second contact surface 532, which is parallel to the radial
direction, at the radially outside end part of the second wall
surface 521. The second contact surface 532 is in contact with the
first contact surface 531 of the scroll piece 2.
[0062] As shown in FIGS. 1 and 3, an outer peripheral surface 311
of the shroud press-fit portion 31 is brought in contact with an
inner peripheral surface 112 of the intake port 11 with no space by
press-fitting the shroud press-fit portion 31 into the inside of
intake port 11, and at the same time, the second contact surface
532 is made abut on the first contact surface 531. Thus, the first
contact surface 531 and the second contact surface 532 is brought
in contact with each other to form the contact portion 53 and to
form an annular space, i.e. the refrigerant flow path 5 between the
first flow-path formation part 51 and the second flow-path
formation part 52. The first wall surface 511 of the first
flow-path formation part 51 and the second wall surface 521 of the
second flow-path formation part 52 form the inside surface 54 of
the refrigerant flow path 5. As shown in FIG. 3, the contact
portion 53 is positioned on the outermost periphery of the inside
surface 54 in the refrigerant flow path 5.
[0063] As shown in FIG. 1, the contact portion 53 has the groove 55
formed therein. The groove 55 is formed by recessing the inside
surface 54 of the refrigerant flow path 5 outwardly in the radial
direction and is continuous in the circumferential direction to
form an annular shape. The groove 55 has a V shape, in other words,
a shape notched into wedged shape outwardly in the radial direction
in the cross section parallel to the shaft direction. The deepest
position 551 of the groove 55 is positioned on the boundary between
the first flow path formation part 51 and the second flow path
formation part 52. As shown in FIGS. 2 and 3, an imaginary circle
16 centered on a shaft center 13a of the compressor impeller 13 is
positioned inside of the groove 55.
[0064] In the present embodiment, the groove 55 is formed to have a
shape notched into a V shape outwardly in the radial direction in
the cross section parallel to the shaft direction. In place of such
a configuration, the groove 55 may have a shape such as a U shape
or a circular-arc shape notched outwardly in the radial direction
in the cross section parallel to the shaft direction. Also in such
a configuration, the deepest position 551 of the groove 55 is
preferably positioned on the boundary between the first flow path
formation part 51 and the second flow path formation part 52.
Further, although in the present embodiment, the groove 55 is
formed by notching both of the first flow path formation part 51
and the second flow path formation part 52, the groove 55 may be
formed by notching either one of the first flow path formation part
51 and the second flow path formation part 52.
[0065] The groove 55 is filled with a sealing material 56. The
kinds of the sealing material 56 are not limited to specific ones,
but are preferably selected to have a quick-drying property. For
instance, the sealing material to be used as a liquid gasket can be
used. In the present embodiment, the sealing material 56 enters
also into a space between the first contact surface 531 and the
second contact surface 532.
[0066] In the present embodiment, as shown in FIG. 3, the first
contact surface 531 and the second contact surface 532 as the
boundary between the first flow-path formation part 51 and the
second flow-path formation part 52 at the contact portion 53 are
parallel to a surface perpendicular to the shaft direction. The
scroll piece 2 has a stepped portion 57 that is formed outside of
the contact portion 53 in the radial direction and protrudes toward
the Y2 side. The shroud piece 3 has a stepped opposing portion 58
cut along the contour of the stepped portion 57. It is noted that
the first contact surface 531 and the second contact surface 532
are brought in contact with each other, but the stepped portion 57
and the stepped opposing portion 58 are not brought in contact with
each other.
[0067] Next, a method for manufacturing the housing 1 for a
turbocharger according to the present embodiment will be
described.
[0068] The method for manufacturing the housing 1 for a
turbocharger includes a preparation step S1, an assembling step S2,
a providing step S3, a filling step S4, and a curing step S5, as
shown in FIG. 4.
[0069] Firstly in the preparation step S1, the scroll piece 2, the
shroud piece 3, and the outer periphery piece 4 are prepared. The
scroll piece 2, the shroud piece 3, and the outer periphery piece 4
are separately formed by die casting. As shown in FIG. 5, in
preparation of the shroud piece 3, a shroud piece precursor 3a
serving as a raw material for the shroud piece 3 is firstly molded
by die casting. In the shroud piece precursor 3a, a shroud surface
22 and an inside surface 312 of the shroud press-fit portion 31
have not been formed, and thus an inside surface 22a of the shroud
piece precursor 3a is cylindrical. Except for this, the shroud
piece precursor 3a has an outer shape equivalent to that of the
shroud piece 3.
[0070] Next in the assembling step S2, the shroud press-fit portion
31 of the shroud piece precursor 3a is press-fitted into the inside
of the intake port formation part 110 of the scroll piece 2 in the
direction as indicated by an arrow P in FIG. 5. The second contact
surface 532 of the shroud piece precursor 3a is made abut on the
first contact surface 531 of the scroll piece 2. In this way, as
shown in FIG. 6, the refrigerant flow path 5 composed of an annular
space is formed between the first flow-path formation part 51 and
the second flow-path formation part 52. The penetration hole 513
formed in the scroll piece 2 is made communicate with the
refrigerant flow path 5.
[0071] Subsequently in the providing step S3, the sealing material
56 having a fluidity is fed from the penetration hole 513 to the
refrigerant flow path 5 to provide the sealing material 56 to the
refrigerant flow path 5. In the providing step S3, the sealing
material 56 is in the state of staying in the bottom of the
refrigerant flow path 5. The amount of the seal material 56 to be
fed is not specified. In the present embodiment, the amount is
adjusted to be equivalent to the volume of the groove 55.
[0072] As shown in FIG. 7, in the filling step S4, the scroll piece
2 and the shroud piece precursor 3a which have been assembled to
each other are rotated around the shaft center 13a of the
compressor impeller 13. Due to a centrifugal force acting on the
sealing material 56 at that time, the groove 55 that is positioned
on the outermost periphery of the inside of the refrigerant flow
path 5 is filled with the sealing material 56. The filling step S4
is continuously performed until the groove 55 is uniformly filled
with almost all amount of the sealing material 56 fed into the
refrigerant flow path 5, and the refrigerant flow path 5, in
substance, has no sealing material 56 flowing therethrough. In the
present embodiment, lathe machining for forming the shroud surface
22 on the shroud piece precursor 3a is performed in the filling
step S4. In the lathe machining, an assembled structure composed of
the scroll piece 2 and the shroud piece precursor 3a is rotated
around the shaft center 13a of the compressor impeller 3 in order
to cut the inside surface 22a of the shroud piece precursor 3a. In
the present embodiment, the filling step S4 is performed utilizing
this rotation.
[0073] Subsequently, in the curing step S5, the state of the
sealing material 56 held in the groove 55 is maintained for a
predetermined period while the rotation is continued. Thus, the
sealing material 56 is cured in the state of being held in the
groove 55. If the sealing material 56 having a quick-drying
property is used, the sealing material 56 can be cured in the state
of being held in the groove 55 during the lathe machining. After
the sealing material 56 has been cured, the outer periphery piece 4
is press-fitted into the scroll piece 2 to produce the housing 1
for a turbocharger.
[0074] In the housing 1 for a turbocharger, the penetration hole
513 communicating with the refrigerant flow path 5 shown in FIG. 3
is connected to a refrigerant introduction tube and a refrigerant
discharge tube which are not shown in any figure. The diffuser
surface 34 can be cooled by flowing the refrigerant through the
refrigerant flow path 5 via the refrigerant introduction tube and
the refrigerant discharge tube.
[0075] In the present embodiment, the sealing material 56 is fed
into the refrigerant flow path 5 in the providing step S3 after the
assembling step S2. Instead, the providing step S3 in which the
sealing material 56 is applied to at least one of the first
flow-path formation part 51 and the second flow-path formation part
52 may be performed prior to the assembling step S2. In such a
configuration, it is preferable to use a sealing material having
high viscosity as the sealing material 56 in consideration of the
workability in the assembling step S2 to be performed after the
providing step S3 and to apply the sealing material to a portion
for forming the groove 55 in the first flow-path formation part 51
or the second flow-path formation part 52, as shown in FIG. 5. In
addition, a sealing material such as FIPG may be applied to at
least one of the first contact surface 531 and the second contact
surface 532 in the providing step S3 prior to the assembling step
S2.
[0076] Hereinafter, operational effects of the housing for a
turbocharger according to the present embodiment will be described
in detail.
[0077] According to the housing 1 for a turbocharger of the present
embodiment, the housing 1 for a turbocharger is dividedly formed,
and the refrigerant flow path 5 is defined by the first flow-path
formation part 51 of the scroll piece 2 and the second flow-path
formation part 52 of the shroud piece 3, both of which are formed
respectively in each opposing part of the scroll piece 2 and the
shroud piece 3 facing each other. At the position corresponding to
the outermost periphery of the inside surface 54 of the refrigerant
flow path 5, the contact portion 53 in which the first flow path
formation part 51 and the second flow path formation part 52 are
brought into contact with each other is formed. The contact portion
53 has the groove 55 that is formed by recessing the inside surface
54 of the refrigerant flow path 5 outwardly in a radial direction
and is continuous in the circumferential direction. The groove 55
is filled with the sealing material 56 for sealing the contact
portion 53. In such a configuration, the space between the first
flow path formation part 51 and the second flow path formation part
52, which forms the refrigerant flow path 5, can be sealed only by
filling the groove 55 with the sealing material 56. Consequently,
it is not necessary to interpose an O-ring between the first flow
path formation part 51 and the second flow path formation part 52,
and thus the assembling workability is satisfactory. Further,
because the O-ring itself is not necessary, reduction of the parts
count can be achieved.
[0078] Further, the housing 1 for a turbocharger is dividedly
formed and includes the scroll piece 2 and the shroud piece 3. The
scroll chamber 12 is formed by assembling at least both pieces to
each other. Thus, the scroll chamber 12 can be formed to have a
circular cross section, and the scroll chamber formation part 120
can be formed into a shape having no undercut, which can be formed
by die-cutting. As a result, the scroll chamber 12 can be more
easily formed by die casting, while enhancing compression
efficiency of the supplied air. In the present embodiment, the
housing 1 for a turbocharger is of a three-piece structure that is
composed of the scroll piece 2, the shroud piece 3, and the outer
periphery piece 4. The housing 1 composed of the scroll piece 2 and
the shroud piece 3 as a two-piece structure also exhibits the
operational effects equivalent to those in the three-piece
structured housing.
[0079] Further, the refrigerant flow path 5 in the housing 1 of the
present embodiment can be formed without necessity to largely
change the basic configuration of the scroll piece and/or shroud
piece in the conventional housings for a turbocharger, so that the
refrigerant flow path 5 can be readily applied to the conventional
housings for a turbocharger.
[0080] In the present embodiment, the groove 55 is formed such that
the imaginary circle 16 centered on the shaft center 13a of the
compressor impeller 13 is positioned inside of the groove 55. In
such a configuration, it becomes easy to fill the groove 55
uniformly with the sealing material 56 by utilizing the centrifugal
force generated by rotation around the shaft center 13a of the
compressor impeller 13, which further improves assembling
workability.
[0081] In the present embodiment, the groove 55 has a shape notched
into a V shape outwardly in the radial direction such that the
deepest position 551 of the groove 55 in a cross section including
the shaft center 13a of the compressor impeller 13 is positioned on
the boundary between the first flow path formation part 51 and the
second flow path formation part 52. In such a configuration, the
sealing material 56 in the groove 55 is easily held in the groove
55, and easily enters into a space between the first flow path
formation part 51 and the second flow path formation part 52 at the
contact portion 53. Consequently, the sealability between the first
flow path formation part 51 and the second flow path formation part
52 can be improved.
[0082] The second wall surface 521 of the second flow path
formation part 52 may be formed as an inclined surface that
inclines gently towards the groove 55. In such a configuration, the
sealing material 56 easily reaches the groove 55 along the second
wall surface 521 in the filling step S4.
[0083] The sealing material 56 may be provided between the scroll
piece 2 and the shroud piece 3 at the contact portion 53 and seal a
space between the scroll piece 2 and the shroud piece 3. In such a
configuration, the sealability between the scroll piece 2 and the
shroud piece 3 at the contact portion 53 can be further
improved.
[0084] In the present embodiment, the first contact surface 531 of
the scroll piece 2 and the second contact surface 532 of the shroud
piece 3 at the contact portion 53 are parallel to a surface
perpendicular to the shaft direction. In such a configuration, the
sealing material 56 in the groove 55 easily enters into a space
between the first flow path formation part 51 and the second flow
path formation part 52 at the contact portion 53 by utilizing the
centrifugal force generated by rotation around the shaft center 13a
of the compressor impeller 13. Consequently, the sealability
between the first flow path formation part 51 and the second flow
path formation part 52 can be further improved.
[0085] In the present embodiment, the scroll piece 2 has the
stepped portion 57 that is formed outside of the contact portion 53
in the radial direction and protrudes toward the Y2 side. The
shroud piece 3 has the stepped opposing portion 58 cut along the
contour of the stepped portion 57. In such a configuration, the
sealing material 56 that has flowed into the space between the
first contact surface 531 and the second contact surface 532 from
the deepest position 551 of the groove 55 in the filling step S4
can be prevented from escaping into the scroll chamber 12.
Consequently, the sealing material 56 easily stays in the groove 55
and the space between the first contact surface 531 and the second
contact surface 532, so that the sealability between the first
flow-path formation part 51 and the second flow-path formation part
52 can be further improved. In the present embodiment, the stepped
portion 57 and the stepped opposing portion 58 are provided each
singly. Besides, the stepped portion 57 may be formed into a shape
having plural steps, and the stepped opposing portion 58 may be
formed into a shape having plural steps formed along the contour of
the plural steps of the stepped portion 57. Such a configuration
can more surely prevent the sealing material 56 from escaping into
the scroll chamber 12, so that the sealability between the first
flow-path formation part 51 and the second flow-path formation part
52 can be further improved.
[0086] The method for manufacturing the housing for a turbocharger
according to the present embodiment includes:
[0087] the preparation step S1 of preparing the scroll piece 2 and
the shroud piece 3 (the shroud piece precursor 3a);
[0088] the assembling step S2 of assembling the shroud piece 2 to
the scroll piece 3 (the shroud piece precursor 3a) by
press-fitting, and bringing the first flow-path formation part 51
into contact with the second flow-path formation part 52, thereby
forming the refrigerant flow path 5 composed of the annular
space;
[0089] the providing step S3 of providing the sealing material 56
having a fluidity by feeding the sealing material 56 to the
refrigerant flow path 5 after the assembling step S2, or by
applying the sealing material 56 to at least one of the first
flow-path formation part 51 and the second flow-path formation part
52 prior to the assembling step S2;
[0090] the filling step S4 of filling the groove 55 with the
sealing material 56 by rotating the scroll piece 2 and the shroud
piece 3 (the shroud piece precursor 3a) around the shaft center 13a
of the compressor impeller 13; and
[0091] the curing step S5 of curing the sealing material 56 in the
groove 55.
[0092] In this method, the sealing material 56 can be easily filled
into the groove 55 in the filling step S4.
[0093] In the present embodiment, lathe machining for forming the
shroud surface 22 is performed in the filling step S4
simultaneously with filling the groove 55 with the sealing material
56. According to such a configuration, the groove 55 can be filled
with the sealing material 56 simultaneously with formation of the
shroud surface 22, so that the manufacturing process can be
simplified.
[0094] The present invention is not limited to the aforementioned
embodiments and modifications, and can be applied to various
embodiments and modifications within the scope that does not extend
beyond the purposes of the present invention.
* * * * *