U.S. patent application number 15/531567 was filed with the patent office on 2017-11-16 for impeller and rotary machine.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. The applicant listed for this patent is MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Ryoji OKABE, Yasunori WATANABE.
Application Number | 20170328372 15/531567 |
Document ID | / |
Family ID | 56091407 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170328372 |
Kind Code |
A1 |
WATANABE; Yasunori ; et
al. |
November 16, 2017 |
IMPELLER AND ROTARY MACHINE
Abstract
This impeller is equipped with: an impeller body for rotating
around an axis along with a rotating shaft, formed from a resin and
shaped as a disk; compressor blades provided on a hub surface of
the impeller body; and a reinforcing ring which is formed from a
resin and reinforcing fibers in a ring shape extending in the
circumferential direction, and engages, from the outer peripheral
side, a step section formed in the back surface of the impeller
body and having a fitting surface facing the outer peripheral
side.
Inventors: |
WATANABE; Yasunori; (Tokyo,
JP) ; OKABE; Ryoji; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES, LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
56091407 |
Appl. No.: |
15/531567 |
Filed: |
October 9, 2015 |
PCT Filed: |
October 9, 2015 |
PCT NO: |
PCT/JP2015/078778 |
371 Date: |
May 30, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F05D 2300/603 20130101;
F04D 17/10 20130101; F04D 29/284 20130101; F04D 29/023
20130101 |
International
Class: |
F04D 29/02 20060101
F04D029/02; F04D 29/28 20060101 F04D029/28; F04D 17/10 20060101
F04D017/10 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 2014 |
JP |
2014-245157 |
Claims
1. An impeller comprising: an impeller body that is formed of a
resin, forms a disk-like shape, and rotates about a rotation center
axis together with a rotating shaft; a plurality of blades provided
on a front surface side of the impeller body; and a reinforcing
ring that is formed on a back surface of the impeller body, is
fitted to a step section, having a surface facing an outer
peripheral side, from the outer peripheral side, is formed of a
resin and reinforcing fibers, and forms an annular shape in a
circumferential direction of the impeller body.
2. The impeller according to claim 1, wherein the step section is
formed at a position of 2/3 of a diameter dimension between the
rotation center axis and an outer peripheral end of the impeller
body from the rotation center axis.
3. The impeller according to claim 1, wherein the step section is
formed such that the center of the reinforcing ring in a radial
direction is located at a position that is larger than 0.1 times a
diameter dimension between the rotation center axis and an outer
peripheral end of the impeller body from the rotation center axis
and is smaller than the diameter dimension.
4. The impeller according to claim 1, wherein the impeller body is
provided with a boss part that protrudes from the back surface and
has the rotating shaft fitted thereto, and wherein the step section
is formed at the boss part.
5. The impeller according to claim 1, wherein a width dimension of
the reinforcing ring in a radial direction and a blade thickness
dimension of the blades in the circumferential direction are the
same, and a thickness dimension of the reinforcing ring in a
direction of the rotation center axis is larger than the width
dimension of the reinforcing ring in the radial direction.
6. The impeller according to claim 1, wherein the reinforcing ring
is disposed such that the reinforcing fibers extend in the
circumferential direction of the impeller body.
7. An impeller comprising: an impeller body that is formed of a
resin, forms a disk-like shape, and rotates about a rotation center
axis together with a rotating shaft; a plurality of blades provided
on a front surface side of the impeller body; and a reinforcing
ring that is formed on a back surface of the impeller body, is
provided at a step section, having a surface facing an outer
peripheral side, from the outer peripheral side, is formed of only
reinforcing fibers, and forms an annular shape in a circumferential
direction of the impeller body.
8. The impeller according to claim 1, further comprising: a second
reinforcing ring that is disposed in the circumferential direction
of the impeller body inside the impeller body and forms an annular
shape.
9. A rotary machine comprising: the impeller according to claim 1;
and a rotating shaft that is attached to the impeller and rotates
together with the impeller.
10. The impeller according to claim 2, wherein a width dimension of
the reinforcing ring in a radial direction and a blade thickness
dimension of the blades in the circumferential direction are the
same, and a thickness dimension of the reinforcing ring in a
direction of the rotation center axis is larger than the width
dimension of the reinforcing ring in the radial direction.
11. The impeller according to claim 3, wherein a width dimension of
the reinforcing ring in a radial direction and a blade thickness
dimension of the blades in the circumferential direction are the
same, and a thickness dimension of the reinforcing ring in a
direction of the rotation center axis is larger than the width
dimension of the reinforcing ring in the radial direction.
12. The impeller according to claim 4, wherein a width dimension of
the reinforcing ring in a radial direction and a blade thickness
dimension of the blades in the circumferential direction are the
same, and a thickness dimension of the reinforcing ring in a
direction of the rotation center axis is larger than the width
dimension of the reinforcing ring in the radial direction.
13. The impeller according to claim 2, wherein the reinforcing ring
is disposed such that the reinforcing fibers extend in the
circumferential direction of the impeller body.
14. The impeller according to claim 3, wherein the reinforcing ring
is disposed such that the reinforcing fibers extend in the
circumferential direction of the impeller body.
15. The impeller according to claim 4, wherein the reinforcing ring
is disposed such that the reinforcing fibers extend in the
circumferential direction of the impeller body.
16. The impeller according to claim 5, wherein the reinforcing ring
is disposed such that the reinforcing fibers extend in the
circumferential direction of the impeller body.
17. The impeller according to claim 2, further comprising: a second
reinforcing ring that is disposed in the circumferential direction
of the impeller body inside the impeller body and forms an annular
shape.
18. The impeller according to claim 3, further comprising: a second
reinforcing ring that is disposed in the circumferential direction
of the impeller body inside the impeller body and forms an annular
shape.
19. The impeller according to claim 4, further comprising: a second
reinforcing ring that is disposed in the circumferential direction
of the impeller body inside the impeller body and forms an annular
shape.
20. The impeller according to claim 5, further comprising: a second
reinforcing ring that is disposed in the circumferential direction
of the impeller body inside the impeller body and forms an annular
shape.
Description
TECHNICAL FIELD
[0001] The invention relates to an impeller provided in a rotary
machine, and a rotary machine including an impeller.
[0002] Priority is claimed on Japanese Patent Application No.
2014-245157, filed Dec. 3, 2014, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] While the global efforts of earth environment preservation
proceed, intensification of regulations regarding exhaust gas or
fuel efficiency in internal combustion engines, such as engines of
automobiles is under way. Turbochargers are rotary machines that
can enhance effects of fuel efficiency improvement and CO.sub.2
reduction by sending compressed air into an engine to combust fuel
compared to natural intake engines.
[0004] In the turbochargers, a turbine is rotationally driven with
exhaust gas of an engine, thereby rotating an impeller of a
centrifugal compressor. The air compressed by the rotation of the
impeller is raised in pressure by being reduced in speed by a
diffuser, and is supplied to the engine through a scroll flow
passage. In addition, as methods for driving the turbochargers, not
only methods of being driven with exhaust gas but also, for
example, methods using electric motors, methods using prime movers,
and the like are known.
[0005] As an impeller of a turbocharger, an impeller using a
complex material (hereinafter referred to as a resin) of synthetic
resins, such as carbon fiber reinforced plastic, is known as
described in, for example, PTL 1. Here, such a resin impeller has
low rigidity compared to a metallic impeller, and if the resin
impeller rotates, the amount of deformation thereof becomes large
under the influence of a centrifugal force. For this reason, a boss
hole into which a rotating shaft is fitted may be increased in
diameter, and rotation balance may be impaired.
[0006] In view of such a problem, in the impeller described in PTL
1, the deformation of the impeller by the centrifugal force is
suppressed by providing a back surface part with a metallic
ring.
CITATION LIST
Patent Literature
[0007] [PTL 1] Japanese Unexamined Utility Model Registration
Application Publication No. 3-10040
SUMMARY OF INVENTION
Technical Problem
[0008] As disclosed in PTL 1, since the impeller is formed of the
resin in a case where the metallic ring is used, the materials of
the impeller and the ring are different from each other. Therefore,
the metallic ring has a larger coefficient of linear expansion than
the impeller made of the resin. As a result, there are
possibilities that, depending on operation conditions, a stress
generated in the impeller cannot be distributed to the ring and the
deformation of the impeller cannot be suppressed. Additionally,
since the density of the metal is high compared to the resin, the
diameter of the ring itself may be increased due to the influence
of a centrifugal force, deformation of the impeller cannot be
suppressed, and it is difficult to guarantee the reliability of the
impeller.
[0009] The invention provides an impeller and a rotary machine that
can guarantee reliability even if resin materials are used.
Solution to Problem
[0010] According to a first aspect of the invention, an impeller
includes an impeller body that is formed of a resin, forms a
disk-like shape, and rotates about a rotation center axis together
with a rotating shaft; a plurality of blades provided on a front
surface side of the impeller body; and a reinforcing ring that is
formed on a back surface of the impeller body, is fitted to a step
section, having a surface facing an outer peripheral side, from the
outer peripheral side, is formed of a resin and reinforcing fibers,
and forms an annular shape in a circumferential direction of the
impeller body.
[0011] According to such an impeller, since the reinforcing ring is
formed of the resin and the reinforcing fibers, the material of the
impeller body and the material of the reinforcing ring become
substantially the same. For this reason, a difference between the
coefficients of linear expansion of the impeller body and the
reinforcing ring becomes small. As a result, the constraint force
of the impeller body can be inhibited from decreasing due to an
increase in the diameter of the reinforcing ring caused by thermal
expansion. Moreover, since the density of the resin is low, the
constraint force of the impeller body can be inhibited from
decreasing by the diameter of the reinforcing ring being increased
due to a centrifugal force. Additionally, since the reinforcing
ring includes reinforcing fibers, rigidity can be improved, the
constraint force of the impeller body can be inhibited from
decreasing due to a diameter increase caused by the centrifugal
force of the reinforcing ring itself. Therefore, a centrifugal
force that acts on the impeller body can be distributed to the
reinforcing ring, the stress of the impeller body caused by the
centrifugal force can be reduced, and it is possible to suppress
deformation of the entire impeller.
[0012] According to a second aspect of the invention, the step
section in the above first aspect may be formed at a position of
2/3 of a diameter dimension between the rotation center axis and an
outer peripheral end of the impeller body from the rotation center
axis.
[0013] Since the step section is formed at such a position, the
reinforcing ring is provided at the position of 2/3 of the radial
dimension of the impeller body from the central axis of the
impeller body. By providing the reinforcing ring at such a
position, the stress of the impeller body caused by a centrifugal
force can be reduced more effectively, and deformation of the
entire impeller can be suppressed.
[0014] According to a third aspect of the invention, the step
section in the above first aspect may be formed such that the
center of the reinforcing ring in a radial direction is located at
a position that is larger than 0.1 times a diameter dimension
between the rotation center axis and an outer peripheral end of the
impeller body from the rotation center axis and is smaller than the
diameter dimension.
[0015] Since the step section is formed at such a position, the
stress of the impeller body caused by a centrifugal force can be
reduced more effectively, and deformation of the entire impeller
can be suppressed.
[0016] According to a fourth aspect of the invention, the impeller
body in the above first aspect may be provided with a boss part
that protrudes from the back surface and has the rotating shaft
fitted thereto, and the step section may be formed at the boss
part.
[0017] According to the above aspect, the reinforcing ring is
provided at the boss part provided in the impeller body.
Accordingly, a stress caused by a centrifugal force at the boss
part can be reduced, and deformation of the entire impeller can be
suppressed.
[0018] According to a fifth aspect of the invention, a width
dimension of the reinforcing ring in a radial direction and a blade
thickness dimension of the blades in the circumferential direction
in the first to fourth aspects may be the same, and a thickness
dimension of the reinforcing ring in a direction of the rotation
center axis may be larger than the width dimension of the
reinforcing ring in the radial direction.
[0019] Since the reinforcing ring is formed with such a dimension,
the stress of the impeller body caused by a centrifugal force can
be reduced more effectively, and deformation of the entire impeller
can be suppressed.
[0020] According to a sixth aspect of the invention, the
reinforcing ring in the first to fifth aspects may be disposed such
that the reinforcing fibers extend in the circumferential direction
of the impeller body.
[0021] If a centrifugal force acts on the reinforcing ring, a
tensile force acts in the circumferential direction. For this
reason, since the reinforcing fibers extends in the circumferential
direction that is a direction in which this tensile force acts,
deformation of the reinforcing ring by such a tensile force itself
can be suppressed. Therefore, the constraint force of the impeller
body can be inhibited from decreasing, and a centrifugal force that
acts on the impeller body can be distributed to the reinforcing
ring. Therefore, the stress of the impeller body can be reduced,
and deformation of the entire impeller can be suppressed.
[0022] According to a seventh aspect of the invention, an impeller
includes an impeller body that is formed of a resin, forms a
disk-like shape, and rotates about a rotation center axis together
with a rotating shaft; a plurality of blades provided on a front
surface side of the impeller body; and a reinforcing ring that is
formed on a back surface of the impeller body, is provided at a
step section, having a surface facing an outer peripheral side,
from the outer peripheral side, is formed of only reinforcing
fibers, and forms an annular shape in a circumferential direction
of the impeller body.
[0023] According to such an impeller, since the reinforcing ring is
formed of only the reinforcing fibers, a difference between the
coefficients of linear expansion of the impeller body and the
reinforcing ring becomes small. As a result, the constraint force
of the impeller body can be inhibited from decreasing due to an
increase in the diameter of the reinforcing ring caused by thermal
expansion. Additionally, since the density of the carbon fibers is
low, the constraint force of the impeller body can be inhibited
from decreasing by the diameter of the reinforcing ring being
increased due to a centrifugal force. Therefore, a centrifugal
force that acts on the impeller body can be distributed to the
reinforcing ring, the stress of the impeller body caused by the
centrifugal force can be reduced, and deformation of the entire
impeller can be suppressed.
[0024] According to an eighth aspect of the invention, the impeller
may further include a second reinforcing ring that is disposed in
the circumferential direction of the impeller body inside the
impeller body in the first to seventh aspects and forms an annular
shape.
[0025] By disposing the second reinforcing ring inside the impeller
body made of the resin in this way, the rigidity of the impeller
body can be further improved. Additionally, since the second
reinforcing ring is disposed inside the impeller body, slip-out
from the impeller body can be suppressed even if a material having
a different coefficient of linear expansion from the impeller body
is used. Therefore, a centrifugal force that acts on the impeller
body can be distributed to the second reinforcing ring, a stress
generated in the impeller body due to the centrifugal force can be
further reduced, and deformation of the entire impeller can be
suppressed.
[0026] According to a ninth aspect of the invention, a rotary
machine includes the impeller in the above first to eighth aspects;
and a rotating shaft that is attached to the impeller and rotates
together with the impeller.
[0027] According to such a rotary machine, since the above
reinforcing ring is provided, the constraint force of the impeller
body can be inhibited from decreasing. Therefore, a centrifugal
force that acts on the impeller body can be distributed to the
reinforcing ring, and a stress generated in the impeller body due
to the centrifugal force can be reduced.
Advantageous Effects of Invention
[0028] According to the above-described impeller and rotary
machine, the reinforcing ring is provided. Thus, even if resin
materials are used, it is possible to guarantee reliability.
BRIEF DESCRIPTION OF DRAWINGS
[0029] FIG. 1 is a longitudinal sectional view illustrating a
turbocharger related to a first embodiment of the invention.
[0030] FIG. 2 is a longitudinal sectional view illustrating an
impeller of the turbocharger related to the first embodiment of the
invention.
[0031] FIG. 3 is a graph of analysis results illustrating effects
of a reinforcing ring in the impeller of the turbocharger of the
first embodiment of the invention, a horizontal axis represents
coordinates in a direction of an axis, and a vertical axis
represents ratios of stresses generated in an impeller body.
Additionally, a dashed line represents cases where no reinforcing
ring is provided, and a solid line represents the impeller of the
first embodiment.
[0032] FIG. 4 is a longitudinal sectional view illustrating an
impeller of a turbocharger related to a second embodiment of the
invention.
[0033] FIG. 5 is a graph of analysis results illustrating effects
of a reinforcing ring in the impeller of the turbocharger of the
second embodiment of the invention, a horizontal axis represents
coordinates in the direction of the axis, and a vertical axis
represents ratios of stresses generated in the impeller body.
Additionally, a dashed line represents cases where no reinforcing
ring is provided, a solid line represents the impeller of the first
embodiment, and a two-dot chain line represents the impeller of the
second embodiment.
[0034] FIG. 6 is a longitudinal sectional view illustrating an
impeller of a turbocharger related to a third embodiment of the
invention.
[0035] FIG. 7 is a longitudinal sectional view illustrating an
impeller of a turbocharger related to a modification example of the
third embodiment of the invention.
DESCRIPTION OF EMBODIMENTS
First Embodiment
[0036] Hereinafter, a turbocharger 1 (rotary machine) related to an
embodiment of the invention will be described.
[0037] As illustrated in FIG. 1, the turbocharger 1 includes a
rotating shaft 2, a turbine 3 and a compressor 4 that rotate
together with the rotating shaft 2, and a housing coupling part 5
that couples the turbine 3 and the compressor 4 and supports the
rotating shaft 2.
[0038] In the turbocharger 1, a turbine 3 is rotated with exhaust
gas G from an engine (not illustrated), and air AR compressed by
the compressor 4 is supplied to the engine with the rotation.
[0039] The rotating shaft 2 extends in a direction of an axis O.
The rotating shaft 2 rotates about the axis O.
[0040] The turbine 3 is disposed on one side (the right side of
FIG. 1) in the direction of the axis O.
[0041] The turbine 3 includes a turbine impeller 14 that has the
rotating shaft 2 attached thereto and has a turbine blade 15, and a
turbine housing 11 that covers the turbine impeller 14 from an
outer peripheral side.
[0042] The rotating shaft 2 is fitted into the turbine impeller 14.
The turbine impeller 14 is rotatable around the axis O together
with the rotating shaft 2.
[0043] The turbine housing 11 covers the turbine impeller 14. A
scroll passage 12, which extending from a leading edge part (an end
part on a radial outer side) of the turbine blade 15 toward the
radial outer side, is formed in an annular shape about the axis O
at a position on the radial outer side, and allows the inside and
outside of the turbine housing 11 to communicate with each other
therethrough, is formed in the turbine housing 11. The turbine
impeller 14 and the rotating shaft 2 are rotated by the exhaust gas
G being introduced into the turbine impeller 14 from the scroll
passage 12.
[0044] A discharge port 13 opening to one side of the axis O is
formed in the turbine housing 11. The exhaust gas G that has passed
through the turbine blade 15 flows toward one side of the axis O,
and is discharged from the discharge port 13 to the outside of the
turbine housing 11.
[0045] The compressor 4 is disposed on the other side (the left
side of FIG. 1) in the direction of the axis O.
[0046] The compressor 4 includes a compressor impeller 24 that has
the rotating shaft 2 attached thereto and has a compressor blade
25, and a compressor housing 21 that covers the compressor impeller
24 from the outer peripheral side.
[0047] The rotating shaft 2 is fitted into the compressor impeller
24. The compressor impeller 24 is rotatable around the axis O
together with the rotating shaft 2.
[0048] The compressor housing 21 covers the compressor impeller 24.
A suction port 23 opening to the other side of the axis O is formed
in the compressor housing 21. The air AR is introduced from the
outside of the compressor housing 21 through the suction port 23
into the compressor impeller 24. Then, by a rotative force from the
turbine impeller 14 being transmitted to the compressor impeller 24
via the rotating shaft 2, the compressor impeller 24 rotates around
the axis O and the air AR is compressed.
[0049] A compressor passage 22, which extend from a trailing edge
part (a downstream end part of a flow of the air AR) of the
compressor blade 25 toward the radial outer side, forms an annular
shape about the axis O at a position on the radial outer side, and
allows the inside and outside of the compressor housing 21 to
communicate with each other therethrough, is formed in the
compressor housing 21. The air AR compressed by the compressor
impeller 24 is introduced to the compressor passage 22, and is
discharged to the outside of the compressor housing 21.
[0050] The housing coupling part 5 is disposed between the
compressor housing 21 and the turbine housing 11 to couple these
housings. The housing coupling part 5 covers the rotating shaft 2
from the outer peripheral side. The housing coupling part 5 is
provided with a bearing 6. The rotating shaft 2 is supported by the
bearing 6 so as to become rotatable relative to the housing
coupling part 5.
[0051] Next, the compressor impeller 24 will be described in detail
with reference to FIG. 2.
[0052] The compressor impeller 24 includes a plurality of the
compressor blades 25, an impeller body 31 that supports the
compressor blades 25 on a hub surface 31aformed on a front surface
side, and a reinforcing ring 41 fitted to a back surface 32 of the
impeller body 31.
[0053] The plurality of compressor blades 25 are provided apart
from each other in a circumferential direction of the rotating
shaft 2 and the impeller body 31. A flow passage FC through which
the air AR flows is formed between the compressor blades 25 that
are adjacent to each other in the circumferential direction. The
compressor blades 25 are formed of a resin in the present
embodiment.
[0054] Here, as resins used for the compressor blades 25, for
example, polyether sulfone (PES), polyether imide (PET), polyether
ether ketone (PEEK), polyether ketone (PEK), polyether ketone
ketone (PEKK), poly ketone sulfide (PKS), polyaryl ether ketone
(PAEK), aromatic polyamide (PA), polyamide imide (PAI), polyimide
(PI), and the like are exemplified.
[0055] In addition, the compressor blades 25 are not limited to the
case where the compressor blades are a resin, and may be made of a
metal or the like.
[0056] The impeller body 31 forms a disk-like shape and supports
the compressor blades 25 on the front surface side, that is, the
compressor blades 25 on the other side in the direction of the axis
O so as to protrude from the hub surface 31a.
[0057] The impeller body 31 is made of the same resin as that of
the above-described compressor blades 25. A step section 36 having
a fitting surface 37 that faces the outer peripheral side (radial
outer side) is formed on the back surface 32 of the impeller body
31, that is, a surface on one side in the direction of the axis
O.
[0058] A boss hole section 31b having the rotating shaft 2 inserted
therethrough and fitted thereinto is formed in a region on a radial
inner side in the impeller body 31.
[0059] More specifically, the step section 36 is formed so as to be
recessed annularly about the axis O from the back surface 32 of the
impeller body 31 toward the other side in the direction of the axis
O, and splits the back surface 32 into a first back surface 32A
located on the radial outer side and a second back surface 32B
located on the radial inner side.
[0060] The first back surface 32A and the second back surface 32B
are formed in a radial direction. The fitting surface 37 is
disposed between the first back surface 32A and the second back
surface 32B, and the step section 36 is formed on the back surface
32 by connecting the first back surface 32A and the second back
surface 32B.
[0061] In addition, the second back surface 32B is inclined so as
to face one side in the direction of the axis O while being curved
in a concave shape to the other side in the direction of the axis O
as it becomes closer to the radial inner side, and is continuous
with the boss hole section 31b after being bent so as to run in the
radial direction from a halfway position.
[0062] In the present embodiment, the fitting surface 37 in this
step section 36 is formed at a position of 2/3 of a diameter
dimension R between the axis O and an outer peripheral end (an end
part on the outermost side in the radial direction) of the impeller
body 31 from the axis O that becomes a rotation center axis of the
impeller body 31.
[0063] The reinforcing ring 41 forms an annular shape, and is
fitted to the step section 36 of the impeller body 31 from the
outer peripheral side. That is, fitting to the step section 36 is
made as an inner peripheral surface thereof contacts the fitting
surface 37 in the step section 36. The reinforcing ring 41 is
formed in a shape and a size such that, in a state where the
reinforcing ring 41 is fitted, the center of the reinforcing ring
41 coincides with the axis O and the reinforcing ring 41 is
smoothly continuous with the second back surface 32B of the
impeller body 31.
[0064] In the present embodiment, the shape of a cross-section
including the axis O forms a rectangular shape, the thickness
dimension in the direction of the axis O coincides with the length
dimension of the fitting surface 37, and the width dimension in the
radial direction is larger than the thickness dimension in the
direction of the axis O.
[0065] The reinforcing ring 41 is formed of the same resin as that
of the compressor blades 25 and the impeller body 31 and further
reinforcing fibers. That is, the reinforcing ring 41 is formed of a
complex material (carbon fiber reinforced plastic) consisting of
resin and carbon fibers, in the present embodiment. Here, the
reinforcing fibers in the reinforcing ring 41 are not limited to
the carbon fibers, and may be glass fibers, Whisker, and the
like.
[0066] The reinforcing ring 41 may be provided so as to be fitted
into the impeller body 31 by insert molding, or may be provided by
recoating the fitting surface 37 in the step section 36 with a
fiber reinforcing resin.
[0067] According to the turbocharger 1 of the present embodiment
described above, since the reinforcing ring 41 of the compressor
impeller 24 is formed of the complex material including the resin,
the material of the reinforcing ring 41 and the material of the
impeller body become substantially the same. For this reason, a
difference between the coefficients of linear expansion of the
impeller body 31 and the reinforcing ring 41 becomes small. As a
result, the constraint force of the impeller body 31 can be
inhibited from decreasing due to an increase in the diameter of the
reinforcing ring 41 caused by thermal expansion.
[0068] Moreover, the density of the resin is low compared to the
metal or the like. For this reason, the constraint force of the
impeller body 31 can be inhibited from decreasing by the diameter
of the reinforcing ring 41 being increased due to a centrifugal
force.
[0069] Additionally, since the reinforcing ring 41 includes the
carbon fibers as the reinforcing resin, the rigidity thereof can be
improved. For this reason, the constraint force of the impeller
body 31 can be inhibited from decreasing due to a diameter increase
caused by the centrifugal force of the reinforcing ring 41
itself.
[0070] As a result, a centrifugal force that acts on the impeller
body 31 can be distributed to the reinforcing ring 41, and a stress
generated in the impeller body 31 due to the centrifugal force can
be reduced. For this reason, by virtue of the reinforcing ring 41
formed of the complex material including the resin and the
reinforcing fibers, deformation can be sufficiently suppressed even
if the resin is used for the impeller body 31.
[0071] Moreover, the step section 36 of the impeller body is formed
at the position of 2/3 of the diameter dimension R between the axis
O and the outer peripheral end of the impeller body 31 from the
axis O that becomes the rotation center axis of the impeller body
31. For this reason, the reinforcing ring 41 is provided at the
position of 2/3 of the diameter dimension R of the impeller body 31
from the rotation center axis of the impeller body 31.
[0072] Analysis results obtained by plotting the ratios of stresses
generated in the impeller body 31 in a case where the center of the
reinforcing ring 41 in the radial direction is provided so as to be
located at a position of 0.6 (about 2/3) times the diameter
dimension of the impeller body 31 for individual relative position
coordinates of the impeller body 31 in the direction of the axis O
are illustrated in FIG. 3. The ratios of the stresses are ratios in
a case where a maximum value of a stress generated in the impeller
body 31 in the present embodiment is set to about 0.7.
[0073] In this analysis, as a position coordinate in the direction
of the axis O in the compressor impeller 24, an end part position
on the other side of the axis O that becomes a side into which the
air AR flows is set as 0, and an end part position on one side of
the axis O that becomes a side from which the air AR flows is set
as 1.0. Additionally, the formation range of the compressor blades
25 is about 0.3 to 0.8.
[0074] Moreover, as analysis conditions, a thickness dimension b of
the reinforcing ring 41 in the direction of the axis O is 0.03
times the thickness of the impeller body 31 in the direction of the
axis O and a width dimension a of the reinforcing ring 41 in the
radial direction is 0.03 times the external diameter dimension of
the impeller body 31.
[0075] According to the analysis results of FIG. 3, since the
reinforcing ring 41 is provided at the position of about 2/3 of the
diameter dimension R of the impeller body 31, it can be confirmed
that a stress can be markedly reduced at a position where a
relative position coordinate in the direction of the axis O becomes
larger than about 0.6 compared to a case (dashed line) where the
reinforcing ring 41 is not provided.
[0076] Stresses decrease gradually at position coordinates of about
0.95 to about 0.6, and a stress ratio is suppressed to about 0.55
at a position of 0.95. On the other hand, in a case where the
reinforcing ring 41 is not provided, stresses becomes gradually
large as position coordinates become large, and a stress ratio 0.8
is exceeded at a position of about 0.85.
[0077] Therefore, by providing the reinforcing ring 41 at the
position of about 2/3 of the dimension of the radial direction of
the impeller body 31, a stress generated in the impeller body 31
can be more effectively reduced, and deformation of the entire
compressor impeller 24 can be suppressed.
[0078] In addition, in the present embodiment, the fitting surface
37 in this step section 36 is not limited to a case where the
fitting surface is formed at the position of 2/3 of the diameter
dimension R of the impeller body 31 from the rotation center axis
(axis O) of the impeller body 31. The fitting surface has only to
be formed a position closer to the axis O than the position of 2/3
of the radial dimension. By forming the fitting surface 37 at the
position closer to the axis O than the position of 2/3 of the
radial dimension, it is possible to enhance a stress reduction
effect.
[0079] Moreover, the step section 36 may be formed so as to be
larger than 0.1 times the diameter dimension R between the rotation
center axis of the impeller body 31 and the outer peripheral end of
the impeller body 31 from the rotation center axis (axis O) of the
impeller body 31 and such that the center of the reinforcing ring
41 in the radial direction is located at a position smaller than
the diameter dimension R. That is, in a case where a distance
between the center of the reinforcing ring 41 in the radial
direction and the axis O is defined as h, the reinforcing ring 41
may be provided so as to satisfy 0.1R<h<1.0R.
Second Embodiment
[0080] Next, a second embodiment of the invention will be described
with reference to FIG. 4.
[0081] The same constituent elements as those of the first
embodiment will be designated by the same reference signs, and the
detailed description thereof will be omitted.
[0082] The turbocharger 50 of the present embodiment is different
from the first embodiment in the shape of a compressor impeller
51.
[0083] The compressor impeller 51 is provided with a boss part 53
that protrudes from a back surface of an impeller body 52 to one
side in the direction of the axis O.
[0084] The impeller body 52 forms substantially the same shape
substantially as the impeller body 31 of the first embodiment, and
is made of the above-described resin. In the present embodiment, a
back surface 54 of the impeller body 52 extends in the radial
direction, and is curved smoothly toward one side in the direction
of the axis O as it becomes closer to the radial inner side.
[0085] The boss part 53 is formed integrally with the impeller body
52 at a position on the radial inner side in the impeller body 52,
and forms an annular shape about the axis O. A boss hole section
53a that is continuous with the boss hole section 31b is formed at
the boss part 53. The rotating shaft 2 is fitted to the boss hole
section 53a.
[0086] The boss part 53 has a fitting surface 57 that faces the
radial outer side. The fitting surface 57 is smoothly continuous
with the curved back surface 54 of the impeller body 52.
Accordingly, the fitting surface 57 is formed in a rounded shape
that is smoothly curved toward one side in the direction of the
axis O so as to run in the direction of the axis O as it becomes
closer to the radial inner side.
[0087] When an inner peripheral surface 65 of the reinforcing ring
41 contacts the fitting surface 57 of the boss part 53, a
reinforcing ring 61 is fitted to the boss part 53. That is, in the
present embodiment, a step section 56 having the fitting surface 57
is formed at the boss part 53, and the reinforcing ring 61 is
fitted to the step section 56.
[0088] Here, in the reinforcing ring 61 of the present embodiment,
the shape of a cross-section including the axis O does not form a
rectangular shape, and the shape of this cross-section is such that
the inner peripheral surface 65 that faces the radial inner side
becomes a curved surface that forms a convex shape toward the axis
O. The shape of this curved surface corresponds to the curved shape
of the fitting surface 57.
[0089] Additionally, an outer peripheral surface 66 that extends
substantially parallel to the axis O continuously with the inner
peripheral surface 65, which becomes the above curved surface, and
faces the radial outer side, and an axial surface 67 that connects
the inner peripheral surface 65 and the outer peripheral surface 66
together, is orthogonal to the axis O, and faces one side in the
direction of the axis O are formed in the reinforcing ring 61.
[0090] According to the turbocharger 50 of the present embodiment
described above, the material of the reinforcing ring 61 and the
material of the impeller body become substantially the same. For
this reason, a difference between the coefficients of linear
expansion of the impeller body 52 and the reinforcing ring 61
becomes small. As a result, the constraint force of the impeller
body 52 can be inhibited from decreasing due to an increase in the
diameter of the reinforcing ring 61 caused by thermal expansion.
Additionally, since the density of the resin is low compared to the
metal or the like, the constraint force of the impeller body 52 can
be inhibited from decreasing by the diameter of the reinforcing
ring 61 being increased due to a centrifugal force.
[0091] Moreover, since the reinforcing ring 61 includes the carbon
fibers as the reinforcing resin, the constraint force of the
impeller body 52 can be inhibited from decreasing by a diameter
increase caused by the centrifugal force of the reinforcing ring 61
itself, and even if the resin is used for the impeller body 52, it
is possible to sufficiently suppress deformation.
[0092] Analysis results obtained by plotting the ratios of stresses
generated in the impeller body 52 in a case where the reinforcing
ring 61 is provided at the boss part 53 of the impeller body 52 for
each relative position coordinate of the impeller body 52 in the
direction of the axis O are illustrated in FIG. 5. Additionally,
the formation range of the boss part 53 is within a range of 0 to
1.0.
[0093] In this analysis, the thickness dimension of the reinforcing
ring 61 in the direction of the axis O is 0.15 times the thickness
of the impeller body 31 in the direction of the axis O and the
width dimension of the reinforcing ring 61 in the radial direction
is 0.05 times the external diameter of the impeller body 31. The
other analysis conditions are the same as those illustrated in FIG.
3 in the first embodiment.
[0094] According to the analysis results of FIG. 5, since the
reinforcing ring 61 is provided at the position (a position where a
relative position coordinate larger than about 0.9) of the boss
part 53 of the impeller body 52, it can be confirmed that a stress
can be markedly reduced at a position where a relative position
coordinate in the direction of the axis O becomes larger than about
0.6 compared to a case (dashed line) where the reinforcing ring 61
is not provided. Stresses decrease gradually at position
coordinates of about 0.6 to about 0.9, and a stress ratio can be
suppressed to about 0.25 at a position of about 0.9, that is, at a
portion where the impeller body 52 and the boss part 53 are
connected together.
[0095] Therefore, by providing the reinforcing ring 61 at the boss
part 53 of the impeller body 52, a stress caused by a centrifugal
force in the boss part 53 can be reduced, a stress generated in the
impeller body 52 can be reduced, and deformation of the entire
compressor impeller 51 can be further suppressed.
Third Embodiment
[0096] Next, a third embodiment of the invention will be described
with reference to FIG. 6.
[0097] The same constituent elements as those of the first and
second embodiments will be designated by the same reference signs,
and the detailed description thereof will be omitted.
[0098] In a turbocharger 70 of the present embodiment, the
compressor impeller 24 (or the compressor impeller 51 of the second
embodiment) of the first embodiment further includes a second
reinforcing ring 71.
[0099] An annular groove part 75 of the rotating shaft 2 that is
recessed to the radial outer side and runs in the circumferential
direction is formed in an inner peripheral surface of the boss hole
section 31b.
[0100] As the annular groove part 75, an inside groove part 75a
that opens to the inner peripheral surface of the boss hole section
31b, extends to the radial outer side, and forms a rectangular
shape as the shape of a cross-section including the axis O, and an
outside groove part 75b that communicates with the inside groove
part 75a, extends to the radial outer side, and forms a rectangular
shape, which protrudes to both sides of the axis O from the inside
groove part 75a, as the shape of a cross-section including the axis
O are formed.
[0101] That is, the annular groove part 75 has a T-shaped
cross-section.
[0102] The second reinforcing ring 71 is disposed inside the
annular groove part 75 of the impeller body 31. Namely, the second
reinforcing ring 71 has a base part 72 that has a rectangular
cross-section corresponding to the inside groove part 75a and forms
an annular shape in the circumferential direction of the impeller
body 31, and an engaging part 63 that extends to both sides in the
direction of the axis O from the base part 72, on the radial outer
side closer to the inside of the impeller body 31 than the base
part 72 continuously with the base part 72.
[0103] The second reinforcing ring 71 is disposed without a gap
inside the annular groove part 75. The base part 72 is exposed to
the inner peripheral surface of the boss hole section 31b and is
flush with the inner peripheral surface. In this way, the second
reinforcing ring 71 forms an annular shape about the axis O and has
a T-shaped cross-section, in a state where the second reinforcing
ring is disposed inside the impeller body 31.
[0104] The second reinforcing ring 71 is formed of a complex
material including a thermosetting resin and reinforcing fibers.
Here, as the reinforcing fibers, similar to the reinforcing ring
41, carbon fibers, glass fibers, Whisker, and the like can be used.
Additionally, as the thermosetting resin, phenol resins, epoxy
resins, melamine resins, silicon resins, and the like can be
used.
[0105] Here, the second reinforcing ring 71 may be formed of
metallic materials, such as aluminum, instead of the complex
material.
[0106] The second reinforcing ring 71 is provided to be fitted into
the impeller body 31, for example by insert molding.
[0107] According to the turbocharger 70 of the present embodiment
described above, the rigidity of the impeller body 31 can be
improved by disposing the second reinforcing ring 71 inside the
impeller body 31 made of the resin in the compressor impeller 24.
Additionally, since the second reinforcing ring 71 is disposed
inside the impeller body 31, slip-out from the impeller body 31 can
be suppressed even if a material having a different coefficient of
linear expansion from the impeller body 31 is used. Therefore, a
centrifugal force that acts on the impeller body 31 can be
distributed to the second reinforcing ring 71, a stress generated
in the impeller body 31 due to the centrifugal force can be
reduced, and it is possible to suppress deformation of the entire
compressor impeller 24.
[0108] Moreover, since the second reinforcing ring 71 has the base
part 72, and an engaging part 73 continuous with the base part 72,
when a tensile force acts on the impeller body 31 to the radial
outer side due to the centrifugal force in a case where the
impeller body 31 has rotated, the engaging part 73 is caught inside
the impeller body 31, so that the centrifugal force that acts on
the impeller body 31 can be firmly distributed to the second
reinforcing ring 71. Therefore, it is possible to further reduce
the stress generated in the impeller body 31, and deformation of
the impeller body 31 can be suppressed.
[0109] Additionally, since the second reinforcing ring 71 is formed
of the complex material including the thermosetting resin and the
reinforcing fibers, and thereby the coefficient of linear expansion
of the complex material is small compared to metals, slackening of
the second reinforcing ring 71 with respect to the impeller body 31
due to thermal expansion does not easily occur. Therefore, a
centrifugal force that acts on the impeller body 31 can be
effectively distributed to the second reinforcing ring 71, and it
is possible to further reduce a stress generated in the impeller
body 31.
[0110] Additionally, in a case where the second reinforcing ring 71
is formed of a metallic material, the rigidity of the second
reinforcing ring 71 itself becomes high. Therefore, deformation
does not easily occur when a centrifugal force has acts, and
slackening of the second reinforcing ring 71 with respect to the
impeller body 31 does not easily occur. Therefore, a centrifugal
force that acts on the impeller body 31 can be effectively
distributed to the second reinforcing ring 71, and a stress
generated in the impeller body 31 can be further reduced.
[0111] Here, as illustrated in FIG. 7, the second reinforcing ring
71A may have a christmas tree-shaped cross-section. By including
such a cross-sectional shape, the second reinforcing ring 71A has a
curved engaging surface 80 that is an outer surface that is curved
so as to protrude toward the impeller body 31. By providing the
curved engaging surface 80 in this way, when a tensile force to the
radial outer side caused by a centrifugal force has acted on the
impeller body 31, the concentration of a stress generated in the
impeller body 31 can be suppressed at a position where the second
reinforcing ring 71A and the impeller body 31 contact each other.
For this reason, further suppression of deformation or damage of
the impeller body 31 is possible by the curved engaging surface
80.
[0112] In addition, in the above-described case, the shapes of the
second reinforcing rings 71 and 71A are not limited.
[0113] Additionally, the second reinforcing rings 71 and 71A may be
disposed at a position in the direction of the axis O where a
stress generated in the impeller body 31 reaches a maximum.
[0114] Additionally, the second reinforcing rings 71 and 71A are
not exposed to the inner peripheral surface of the boss hole
section 31b, and may be completely embedded inside the impeller
body 31.
[0115] Although the embodiments of the invention have been
described above in detail, some design changes can also be made
without departing from the technical idea of the invention.
[0116] For example, the sectional shapes of the reinforcing rings
41 and 61 is not limited are not limited to the cases of the
above-described embodiments.
[0117] That is, a circular cross-sectional shape and the like may
be adopted.
[0118] Additionally, the thickness dimension (the thickness
dimension in the circumferential direction) of the compressor
blades 25 may be the same as the width dimension a (refer to FIG.
2) of the reinforcing ring 41 (61) in the radial direction.
[0119] Moreover, the thickness dimension b (refer to FIG. 2) of the
reinforcing ring 41 (61) in the direction of the axis O may be
larger than the width dimension a in the radial direction.
[0120] By doing in this way, the stress of the impeller body 31
(52) generated by a centrifugal force can be more effectively
reduced, and deformation of the entire compressor impeller 24 (51)
can be suppressed.
[0121] Additionally, the reinforcing fibers may be disposed so as
to extend in the circumferential direction of the rotating shaft
2.
[0122] If a centrifugal force acts on the reinforcing ring 41 (61),
a tensile force acts in the circumferential direction such that the
diameter of the reinforcing ring increases. For this reason, if the
reinforcing fibers extends in the circumferential direction that is
a direction in which this tensile force acts, deformation of the
reinforcing ring 41 (61) by such a tensile force itself can be
suppressed. Therefore, the constraint force of the impeller body 31
(52) can be inhibited from decreasing, and a centrifugal force that
acts on the impeller body 31 (52) can be distributed to the
reinforcing ring 41 (61).
[0123] Therefore, the stress of the impeller body 31 (52) can be
reduced, and deformation of the entire compressor impeller 24 (51)
can be suppressed.
[0124] Additionally, the reinforcing ring 41 (61) may be formed of
only the carbon fibers excluding the resin.
[0125] Additionally, the compressor blades 25 and the impeller body
31 (52) may include the same reinforcing fibers as the reinforcing
ring 41 (61) in addition to the resin.
[0126] Additionally, in the above-described embodiments, as the
rotary machine, the turbocharger has been described as an example.
However, the invention may be used for other centrifugal
compressors and the like.
INDUSTRIAL APPLICABILITY
[0127] According to the above-described impeller and rotary
machine, the reinforcing ring is provided. Thus, even if resin
materials are used, it is possible to guarantee reliability.
REFERENCE SIGNS LIST
[0128] 1: TURBOCHARGER
[0129] 2: ROTATING SHAFT
[0130] 3: TURBINE
[0131] 4: COMPRESSOR
[0132] 5: HOUSING COUPLING PART
[0133] 6: BEARING
[0134] 11: TURBINE HOUSING
[0135] 12: SCROLL PASSAGE
[0136] 13: DISCHARGE PORT
[0137] 14: TURBINE IMPELLER
[0138] 15: TURBINE BLADE
[0139] 21: COMPRESSOR HOUSING
[0140] 22: COMPRESSOR PASSAGE
[0141] 23: SUCTION PORT
[0142] 24: COMPRESSOR IMPELLER
[0143] 25: COMPRESSOR BLADE
[0144] 31: IMPELLER BODY
[0145] 31a: HUB SURFACE
[0146] 31b: BOSS HOLE SECTION
[0147] 32: BACK SURFACE
[0148] 32A: FIRST BACK SURFACE
[0149] 32B: SECOND BACK SURFACE
[0150] 36: STEP SECTION
[0151] 37: FITTING SURFACE
[0152] 41: REINFORCING RING
[0153] 50: TURBOCHARGER (ROTARY MACHINE)
[0154] 51: COMPRESSOR IMPELLER
[0155] 52: IMPELLER BODY
[0156] 53: BOSS PART
[0157] 53a: BOSS HOLE SECTION
[0158] 54: BACK SURFACE
[0159] 56: STEP SECTION
[0160] 57: FITTING SURFACE
[0161] 61: REINFORCING RING
[0162] 65: INNER PERIPHERAL SURFACE
[0163] 66: OUTER PERIPHERAL SURFACE
[0164] 67: AXIAL SURFACE
[0165] 70: TURBOCHARGER
[0166] 71, 71A: SECOND REINFORCING RING
[0167] 72: BASE PART
[0168] 73: ENGAGING PART
[0169] 75: ANNULAR GROOVE PART
[0170] 75a: INSIDE GROOVE PART
[0171] 75b: OUTSIDE GROOVE PART
[0172] 80: CURVED ENGAGING SURFACE
[0173] G: EXHAUST GAS
[0174] AR: AIR
[0175] O: AXIS
[0176] FC: FLOW PASSAGE
* * * * *