DESCRIPTION
EXHAUST TURBO SUPERCHARGER
Technical Field
[0001]
The present invention relates to an exhaust turbo supercharger to be used in an
internal combustion engine that serves as a power source in a vessel, motor vehicle
or power generator, in particular, to a VG (variable geometry) type exhaust turbo
supercharger.
Background Art
[0002]
An exhaust turbo supercharger improves the combustion efficiency of an internal
combustion engine by forcefully supplying air into a combustion chamber of the
internal combustion engine to improve output of the internal combustion engine and
improve the properties of exhaust gas of the internal combustion engine.
As such an exhaust turbo supercharger, a variable displacement type exhaust
turbo supercharger disclosed in Patent Document 1 mentioned later is commonly
known for example.
[0003]
This variable displacement type exhaust turbo supercharger has a turbine
housing (turbine casing), inside of which there is formed a spiral flow passage, and a
turbine wheel provided substantially in the center in the radial direction of this turbine
housing. Exhaust gas from an internal combustion engine is supplied into the spiral
flow passage of the turbine housing. The turbine wheel is rotation driven by exhaust
gas supplied into this spiral flow passage.
[0004]
Moreover, this variable displacement type exhaust turbo supercharger has a
compressor housing, inside of which there is formed a spiral flow passage, and a
compressor wheel provided in a substantially radial direction center of the
compressor housing. The compressor wheel is rotation driven to take outside air
into the compressor housing and deliver the outside air that has been taken in into
1

the spiral flow passage in the compressor housing. The spiral flow passage of the
compressor is connected to an air intake system of the internal combustion engine.
Accordingly, the outside air that has been delivered into this spiral flow passage by
the compressor wheel is forcefully delivered to the air intake system of the internal
combustion engine.
[0005]
The turbine wheel and the compressor wheel are linked by a turbine shaft. A
bearing housing is provided between the turbine housing and the compressor
housing. In the bearing housing, there is provided a bearing that supports the
turbine shaft, allowing it to rotate around the axis.
In the bearing housing, on the outer circumference section of an end to be
connected with the turbine housing, there is provided a flange section. In the turbine
housing, on an end to be connected with the bearing housing, there is formed a
plurality of screw holes on the outside of the area that receives the flange section of
the bearing housing. The bearing housing and the turbine housing are connected
by engaging a bolt in each of the screw holes provided in the turbine housing.
Specifically, the bearing housing is fixed on the turbine housing by the flange section
of the bearing housing being pressed against the turbine housing by the head
sections of the bolts that engage with each of the screw holes of the turbine
housing, or by washers attached to the bolt head sections.
Moreover, between the turbine housing and the bearing housing, there is
provided a gasket that prevents exhaust gas that has flowed through an insert
section of the turbine shaft into between the turbine housing and the bearing
housing from leaking to outside of the device. The contact pressure contact
pressure of this gasket with the turbine housing and the bearing housing is
determined by the fastening force of the bolts.
[0006]
In this variable displacement type exhaust turbo supercharger, exhaust gas
introduced from an exhaust system of the internal combustion engine into the spiral
flow passage in the turbine housing rotation-drives the turbine wheel.
As the turbine wheel is rotation driven in this manner, this driving force is
transmitted to the compressor wheel via the turbine shaft, and the compressor
wheel is thereby rotation driven.
2

Thus, the compressor wheel takes outside air into the compressor housing and
delivers the outside air that has been taken in into the spiral flow passage in the
compressor housing. As a result, the outside air that has been taken into the
compressor housing is forcefully supplied into a combustion chamber of the internal
combustion engine.
[0007]
Furthermore, in this variable displacement type exhaust turbo supercharger, in
the turbine housing, there is provided a variable nozzle mechanism for adjusting the
displacement of the turbine.
The variable nozzle mechanism has nozzle vanes arranged on the inner
circumference side of the spiral flow passage in the turbine housing in a plurality of
positions at equal intervals in the circumferential direction of the turbine. Each of the
nozzle vanes is provided so as to be able to respectively change the blade angle
thereof with respect to a nozzle mount attached to the turbine housing.
The variable nozzle mechanism is to adjust a flow speed of exhaust gas
delivered from the spiral flow passage into the turbine housing by adjusting the
blade angle of each of the nozzle vanes. In the variable nozzle mechanism, by
adjusting the flow speed of exhaust gas delivered to the turbine wheel in this
manner, the rotation speed of the turbine wheel is adjusted, and the volume of air
delivered to the air intake system by the compressor wheel can be adjusted.
[0008]
Patent Document 1: Japanese Unexamined Patent Application, Publication No.
2004-156592
Disclosure of Invention
[0009]
While operating the variable displacement type exhaust turbo supercharger, the
turbine housing reaches a high temperature as it receives heat of the exhaust gas
traveling inside. Moreover, since the thread face of the bolt that engages with the
screw hole of the turbine housing is in surface contact with the turbine housing, the
temperature of this bolt becomes high.
On the other hand, in the bearing housing, usually there is provided a lubrication
mechanism that supplies lubricating oil to the bearing to lubricate and cool the
3

bearing. The bearing housing is cooled down by lubricating oil supplied from the
lubrication mechanism and a temperature rise therein is unlikely to occur compared
to the turbine housing.
Therefore, the thermal expansion amount of the bearing housing as a result of
operating the variable displacement type exhaust turbo supercharger is smaller than
the thermal expansion amount of the turbine housing and the bolt. Accordingly,
while operating the variable displacement type exhaust turbo supercharger, the
fastening force of the bolt for fastening the turbine housing and the bearing housing
decreases, and the contact pressure of the gasket decreases,
[0010]
Conventionally, in order to sufficiently ensure the contact pressure of the gasket
even during operation of the variable displacement type exhaust turbo supercharger,
in consideration of a reduction amount in fastening force of the bolt mentioned
above, the fastening torque of the bolt is set higher than the torque required for
simple fixation.
However, in the case where the bolt fastening torque is set higher, a longer
period of time is required for detaching and attaching the bolt, resulting in a low level
of workability in assembly and disassembly of the variable displacement type
exhaust turbo supercharger.
[0011]
Here, in the variable displacement type exhaust turbo supercharger, the turbine
housing and the bearing housing are fixed with the nozzle mount sandwiched
therebetween. In other words, the turbine housing, the bearing housing, and the bolt
serve also as fixing devices for fixing the nozzle mount.
In this construction it is not necessary to separately provide a fixation device for
fixing the nozzle mount. As a result, the number of parts is reduced and production
cost is reduced.
[0012]
However, in such a construction where the nozzle mount is clamped and fixed
between the turbine housing and the bearing housing, the fastening force of the bolt
acts not only as force to fix the turbine housing and the bearing housing but also as
force for the turbine housing and the bearing housing to retain the nozzle mount. In
other words, in this construction, since the fastening force of the bolt is distributed,
4

more reliable fixation of the turbine housing and the bearing housing using the bolt is
required.
[0013]
The present invention takes the above circumstances into consideration, and its
object is to provide an exhaust turbo supercharger that is able to effectively prevent
exhaust gas that has flowed into between the turbine housing and the bearing
housing from leaking to outside of the device, while also providing an excellent level
of workability in assembly and disassembly.
[0014]
In order to solve above problems, the present invention provides following
means.
A first aspect of the present invention provides an exhaust turbo supercharger
having: a turbine housing, into which exhaust gas from an internal combustion
engine is introduced; a turbine wheel which is provided within the turbine housing
and which is rotation-driven by the exhaust gas; a turbine shaft, one end of which is
inserted into the turbine housing, and to which the turbine wheel is attached; a
bearing which supports the turbine shaft; a bearing housing which is connected to
the turbine housing and inside of which the bearing is housed; and a gasket which
seals, in an area outside in the radial direction of the turbine shaft, between the
turbine housing and the bearing housing; wherein a bolt insert hole is formed in the
turbine housing, an internal thread insert made from a heat insulating material is
provided in the bolt insert hole, and the turbine housing and the bearing housing are
detachably fixed by a bolt that engages with the internal thread insert.
[0015]
In the exhaust turbo supercharger according to the first aspect of the present
invention mentioned above, heat transmission between the turbine housing and the
bolt is prevented by the internal thread insert made from a heat insulating material
that is provided in the bolt insert hole of the turbine housing.
As a result, even if the temperature of the turbine housing rises while operating
the exhaust turbo supercharger, since the temperature rise in the bolt is suppressed,
and the thermal expansion amount of the bolt is reduced, a reduction in the
fastening force of the bolt is unlikely to occur.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
5

bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
[0016]
A second aspect of the present invention provides an exhaust turbo supercharger
having: a turbine housing into which exhaust gas from an internal combustion
engine is introduced; a turbine wheel which is provided within the turbine housing
and which is rotation-driven by the exhaust gas; a turbine shaft, one end of which is
inserted into the turbine housing, and to which the turbine wheel is attached; a
bearing which supports the turbine shaft; a bearing housing which is connected to
the turbine housing and inside of which the bearing is housed; and a gasket which
seals, in an area outside in the radial direction of the turbine shaft, between the
turbine housing and the bearing housing; wherein a through hole is formed in the
turbine housing, the turbine housing and the bearing housing are detachably fixed
by a bolt inserted into the through hole, and a nut that engages with the bolt; and an
insert made from a heat insulating material, or an air layer, is provided between an
inner surface of the through hole and the bolt.
[0017]
In the exhaust turbo supercharger according to the second aspect of the present
invention, between the inner surface of the through hole of the turbine housing and
the bolt, there is formed the insert made from a heat insulating material, or the air
layer, and this insert or air layer prevents heat transmission between the turbine
housing and the bolt.
As a result, even if the temperature of the turbine housing rises while operating
the exhaust turbo supercharger, since the temperature rise in the bolt is suppressed,
and the thermal expansion amount of the bolt is reduced, a reduction in the
fastening force of the bolt is unlikely to occur.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
[0018]
Moreover, a third aspect of the present invention provides an exhaust turbo
6

supercharger having: a turbine housing into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
end of which is inserted into the turbine housing, and to which the turbine wheel is
attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein a screw hole is
formed in the turbine housing, heat radiating fins or heat radiating grooves are
formed in the vicinity of the screw hole, and the turbine housing and the bearing
housing are detachably fixed by a bolt that engages with the screw hole.
[0019]
In the exhaust turbo supercharger according to the third aspect of the present
invention, in the vicinity of the screw hole of the turbine housing, heat radiating fins
or heat radiating grooves are provided to increase the area in contact with the
outside air.
Therefore, even if the temperature of the turbine housing rises while operating
the exhaust turbo supercharger, in the vicinity of the screw hole in the turbine
housing, heat is effectively radiated to the surrounding area and the temperature
rise is suppressed.
As a result, temperature rise in the bolt that engages with this screw hole is
suppressed, and the thermal expansion amount of the bolt is reduced. Therefore,
the fastening force of the bolt is unlikely to decrease.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
[0020]
Moreover, a fourth aspect of the present invention provides an exhaust turbo
supercharger having: a turbine housing into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
end of which is inserted into the turbine housing, and to which the turbine wheel is
7

attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein there is formed a
screw hole in the turbine housing; the turbine housing and the bearing housing are
detachably fixed by a bolt that engages with the screw hole; and a through hole is
provided in the bolt along the axis of the bolt.
[0021]
In the exhaust turbo supercharger according to the fourth aspect of the present
invention, on the bolt for fixing the turbine housing and the bearing housing, a
through hole is formed along the axial direction.
As a result, the surface area of the bolt is increased and the amount of heat
radiated from the bolt increases, while the bolt is cooled down by outside air that
flows into the through hole.
As a result, even if the temperature of the turbine housing rises while operating
the exhaust turbo supercharger, since the temperature rise in the bolt is suppressed,
and the thermal expansion amount of the bolt is reduced, a reduction in the
fastening force of the bolt is unlikely to occur.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
In this exhaust turbo supercharger, the screw hole provided in the turbine
housing may be a through hole, or, in the case of a blind screw hole, in the bottom
section of this screw hole a through hole in the area that opposes to a through hole
in a bolt may be provided. In this case, since outside air can more easily flow
through inside the bolt through the hole, a temperature rise in the bolt becomes
more unlikely to occur, and a reduction in the contact pressure on the gasket due to
thermal expansion of the bolt can be effectively prevented.
[0022]
Moreover, a fifth aspect of the present invention provides an exhaust turbo
supercharger having: a turbine housing into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
8

turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
end of which is inserted into the turbine housing, and to which the turbine wheel is
attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein a screw hole is
formed in the turbine housing; the turbine housing and the bearing housing are
detachably fixed by a bolt that engages with the screw hole; and on an inner surface
of the turbine housing in an area in contact with the exhaust gas, a heat shield layer
is formed.
[0023]
In the exhaust turbo supercharger according to the fifth aspect of the present
invention, the heat shield layer provided on the inner surface of the turbine housing
prevents heat transmission from the exhaust gas that has been introduced into the
turbine housing, to the turbine housing.
As a result, even while operating the exhaust turbo supercharger, temperature
rise in the turbine housing is suppressed, and the thermal expansion amounts of the
turbine housing and the bolt that engages with the turbine housing are reduced. As
a result, the fastening force of the bolt is unlikely to decrease.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
Moreover, in this exhaust turbo supercharger, since the heat shielding capacity of
the turbine housing is improved, the efficiency of the turbine can be improved.
Furthermore, in this exhaust gas turbo supercharger, since temperature rise in
the turbine housing can be suppressed, the load on the turbine housing due to heat
stress can be reduced and the durability of the turbine housing can be improved.
[0024]
Moreover, a sixth aspect of the present invention provides an exhaust turbo
supercharger having: a turbine housing into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
9

end of which is inserted into the turbine housing, and to which the turbine wheel is
attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein a screw hole is
formed in the bearing housing, and the turbine housing and the bearing housing are
detachably fixed by a bolt that engages with the screw hole.
[0025]
In the exhaust turbo supercharger according to the sixth aspect of the present
invention mentioned above, the screw hole is provided in the bearing housing,
where the temperature is unlikely to rise, and the turbine housing and the bearing
housing are connected by the bolt that engages with the screw hole.
In other words, in the bolt that connects the turbine housing and the bearing
housing, the thread face, which is the largest area that comes in contact with other
members, is brought in contact with the bearing housing, in which a temperature rise
is unlikely to occur.
Therefore, in this exhaust turbo supercharger, even while operating the exhaust
turbo supercharger, the heat of the turbine housing is unlikely to be transmitted to
the bolt, and thermal expansion amount of the bolt is reduced. As a result, the
fastening force of the bolt is unlikely to decrease.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
Moreover, in this exhaust turbo supercharger, since the head section of the bolt
faces the turbine housing side (end section side of the exhaust turbo supercharger),
tools (such as a spanner) can easily enter in the vicinity of the head section of the
bolt, enabling easy operation of attaching and detaching the bolt.
[0026]
Moreover, a seventh aspect of the present invention provides an exhaust turbo
supercharger having: a turbine housing, into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
10

end of which is inserted into the turbine housing, and to which the turbine wheel is
attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein a screw hole is
formed in the turbine housing; the turbine housing and the bearing housing are
detachably fixed by a bolt that engages with the screw hole; and between a head
section of the bolt and the bearing housing there is provided an elastic member in a
state of being compressed in the axial direction of the bolt.
[0027]
In the exhaust turbo supercharger according to the seventh aspect of the present
invention, between the bolt and the bearing housing there is provided the elastic
member in a state of being compressed in the axial direction of the bolt.
As a result, when a difference occurs between the thermal expansion amounts of
the turbine housing and the bolt and the thermal expansion amount of the bearing
housing, the elastic member returns from its compressed state by this difference
amount, thereby compensating for the difference between these thermal expansion
amounts. Therefore, a decrease in the fastening force of the bolt is unlikely to
occur.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
Here, as the elastic member, for example, a spring such as a conical spring
washer or a bush made from rubber or resin having elasticity may be used.
[0028]
Moreover, an eighth aspect of the present invention provides an exhaust turbo
supercharger having: a turbine housing into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
end of which is inserted into the turbine housing, and to which the turbine wheel is
attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
11

gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein a screw hole is
formed in the turbine housing, the turbine housing and the bearing housing are
detachably fixed by a bolt that engages with the screw hole, and in the bearing
housing, a bolt support section that receives the bolt is able to elastically deform in
the axial direction of the bolt, and the bolt support section receives the bolt in a state
of being elastically deformed to the turbine housing side.
[0029]
In the exhaust turbo supercharger according to the eighth aspect of the present
invention, in the bearing housing, the bolt support section that receives the bolt is
able to elastically deform in the axial direction of the bolt.
This bolt support section receives the bolt in a state of being elastically deformed
toward the turbine housing side.
As a result, when a difference occurs between the thermal expansion amounts of
the turbine housing and the bolt, and thermal expansion amount of the bearing
housing, the bolt support section returns by this amount in the direction that reduces
its elastic deformation, thereby compensating for the difference between these
thermal expansion amounts. Therefore, a decrease in the fastening force of the bolt
is unlikely to occur.
In this exhaust turbo supercharger, since a reduction in the fastening force of the
bolt is unlikely to occur as described above, thereby ensuring the contact pressure
of the gasket, the sealing capacity of the gasket can be ensured without setting the
fastening force of the bolt high.
[0030]
Moreover, a ninth aspect of the present invention provides an exhaust turbo
supercharger having: a turbine housing into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
end of which is inserted into the turbine housing, and to which the turbine wheel is
attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein a screw hole is
12

formed in the turbine housing, in the turbine housing a cylindrical male engaging
section that surrounds the turbine shaft is provided, in the bearing housing there is
provided a female engaging section into which the male engaging section is
inserted, an inner surface of which is fitted together with the male engaging section,
and the turbine housing and the bearing housing are detachably fixed by a bolt that
engages with the screw hole, in a state where the male engaging section and the
female engaging section are fitted together.
[0031]
Here, as mentioned above, even while operating the exhaust turbo supercharger,
the temperature of the bearing housing is unlikely to rise compared to the turbine
housing, and the thermal expansion amount of the bearing housing is smaller than
that of the turbine housing.
In the exhaust turbo supercharger according to the ninth aspect of the present
invention, the male engaging section is provided in the turbine housing, and in the
bearing housing there is provided the female engaging section that is fitted together
with the male engaging section (so called spigot coupling).
Accordingly, when operating this exhaust turbo supercharger, the temperature of
the turbine housing rises, and the male engaging section provided in the turbine
housing also thermal-expands toward the radial direction outside.
On the other hand, the thermal expansion amount of the female engaging section
provided in the bearing housing is smaller than that of the male engaging section.
As a result, when the temperature of the turbine housing rises, the outer
circumference surface of the male engaging section comes in tight contact with the
inner circumference surface of the female engaging section, sealing between the
turbine housing and the bearing housing. Adhesion between the male engaging
section and the female engaging section becomes stronger as the difference
between the thermal expansion amounts of the male engaging section and the
female engaging section (in other words, the difference between the thermal
expansion amounts of the turbine housing and the bearing housing) increases, and
the sealing property between the turbine housing and the bearing housing becomes
more reliable.
As a result, even if a difference occurs between the thermal expansion amounts
of the turbine housing and the bolt, and the bearing housing, so that the fastening
13

force of the bolt decreases, leakage of exhaust gas from between the turbine
housing and the bearing housing is prevented.
Therefore, in this exhaust turbo supercharger, sealing capacity of the gasket can
be ensured without setting the fastening force of the bolt high.
[0032]
Moreover, a tenth aspect of the present invention provides an exhaust turbo
supercharger having: a turbine housing into which exhaust gas from an internal
combustion engine is introduced; a turbine wheel which is provided within the
turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one
end of which is inserted into the turbine housing, and to which the turbine wheel is
attached; a bearing which supports the turbine shaft; a bearing housing which is
connected to the turbine housing and inside of which the bearing is housed; and a
gasket which seals, in an area outside in the radial direction of the turbine shaft,
between the turbine housing and the bearing housing; wherein a screw hole is
formed in the turbine housing, and between the turbine housing and the bearing
housing, there are provided in the following order toward the radial direction outside
of the turbine shaft: a narrow section in which a distance between the turbine
housing and the bearing housing is short; and an expanded section in which a
distance between the turbine housing and the bearing housing is greater than that in
the narrow section; and the turbine housing and the bearing housing are detachably
fixed by a bolt that engages with the screw hole.
[0033]
In the exhaust turbo supercharger according to the tenth aspect of the present
invention mentioned above, between the turbine housing and the bearing housing
there are provided the narrow section and the expanded section, in that order
toward the gasket.
The narrow section serves as an aperture that reduces the pressure of exhaust
gas flowed in from an insertion passage section of the turbine shaft of the turbine
housing to between the turbine housing and the bearing housing.
The exhaust gas that has passed through the narrow section expands when
flowing into the expanded section, reducing the pressure thereof.
As described, in this exhaust turbo supercharger, the pressure applied by
exhaust gas on the gasket can be low. Therefore, even if a difference in the thermal
14

expansion amounts between the turbine housing and the bolt, and the bearing
housing occurs, and the fastening force of the bolt decreases, leakage of exhaust
gas from between the turbine housing and the bearing housing is prevented.
In particular, in the case where the pressure variation of the exhaust gas is
significant, leakage of exhaust gas from between the turbine housing and the
bearing housing can be effectively prevented.
Specifically, as the exhaust gas that has entered between the turbine housing
and the bearing housing passes through the narrow section, a time difference
occurs in the pressure variance with the exhaust gas within the turbine housing.
As a result, in the expanded section, the pressure of exhaust gas is averaged
and the inner pressure of the expanded section becomes lower than the peak
pressure of the exhaust gas.
Therefore, in this exhaust turbo supercharger, sealing capacity of the gasket can
be ensured without setting the fastening force of the bolt high.
[0034]
Here, in the exhaust turbo supercharger according to the tenth aspect mentioned
above, in the turbine housing, there may be provided a bypass flow passage that
continues from the expanded section to the vicinity of an exit of the exhaust gas.
Since almost all the energy of the exhaust gas that has been introduced into the
turbine housing is consumed in rotation driving the turbine wheel, the pressure of the
exhaust gas at the exhaust gas exit of the turbine housing is approximately equal to
atmospheric pressure.
Accordingly, in the case where the pressure of the exhaust gas within the
expanded section is greater than the pressure of the exhaust gas in the vicinity of
the exhaust gas exit of the turbine housing, the exhaust gas within the expanded
section travels through the bypass passage and flows into the vicinity of the exhaust
gas exit of the turbine housing, reducing the inner pressure of the expanded
section.
Therefore, the pressure applied by the exhaust gas to the gasket is further
reduced, and sealing capacity of the gasket can be ensured.
[0035]
According to the present invention, an exhaust turbo supercharger that is able to
effectively prevent exhaust gas that has flowed into between the turbine housing and
15

the bearing housing from leaking to outside of the device, while allowing an excellent
level of workability in assembly and disassembly, can be provided.
Brief Description of Drawings
[0036]
[FIG. 1] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a first embodiment of the present invention.
[FIG. 2] is a partial enlargement of FIG. 1.
[FIG. 3] is a schematic drawing of FIG. 2.
[FIG. 4] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a second embodiment of the present invention.
[FIG. 5] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a third embodiment of the present invention.
[FIG. 6] is a partial plan view showing the construction of the exhaust turbo
supercharger according to the third embodiment of the present invention.
[FIG. 7] is a partial plan view showing another construction example of an
exhaust turbo supercharger according to the third embodiment of the present
invention.
[FIG. 8] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a fourth embodiment of the present invention.
[FIG. 9] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a fifth embodiment of the present invention.
[FIG. 10] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a sixth embodiment of the present invention.
[FIG. 11] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a seventh embodiment of the present invention.
. [FIG. 12] is a vertical sectional view showing another construction example of an
exhaust turbo supercharger according to the seventh embodiment of the present
invention.
[FIG. 13] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to an eighth embodiment of the present invention.
[FIG. 14] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a ninth embodiment of the present invention.
16

[FIG. 15] is a vertical sectional view showing another construction example of an
exhaust turbo supercharger according to the ninth embodiment of the present
invention.
[FIG. 16] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to a tenth embodiment of the present invention.
[FIG. 17] is a vertical sectional view showing the construction of an exhaust turbo
supercharger according to an eleventh embodiment of the present invention.
Explanation of Reference Signs:
[0037]
1 , 51 , 61 , 71 , 81 , 91 , 101 , 111 , 121 , 131 , 141 , 151 Exhaust turbo
supercharger
2 , 52 , 62 , 72 , 82 , 92 Turbine housing
3 Turbine wheel

21 Turbine shaft
22 , 93 , 113 , 123 , 133 Bearing housing
23 Bearing
44 Gasket

46 Bolt insertion hole
48 Bolt
47 Internally threaded insert

56 Through hole
57 Nut
67 Heat radiating fin
69 Heat radiating groove
76a Through hole
88 Heat shield layer
104 Elastic member
114 Bolt support section
127 Male engaging section
128 Female engaging section

146 Narrow section
147 Expanded section
154 Bypass flow passage
17

A Air layer
Best Mode for Carrying Out the Invention
[0038]
Hereunder, embodiments of the present invention are described, with reference
to the drawings.
[First Embodiment]
Hereunder, a first embodiment of the present invention is described, with
reference to FIG. 1 and FIG. 2.
In the present embodiment, an example in which the present invention is applied
to a VG exhaust turbo supercharger is described. The present invention is not
limited to this example and may be applied to a generic exhaust turbo
supercharger.
[0039]
As shown in the vertical sectional view of FIG. 1, an exhaust turbo supercharger
1 according to the present embodiment has a turbine housing 2 inside of which
there is formed a spiral flow passage 2a, and a turbine wheel 3, which is provided in
a substantially radial direction center section of this turbine housing 2. Into the spiral
flow passage 2a of the turbine housing 2, exhaust gas from an internal combustion
engine (not shown in the drawing) is supplied. The turbine wheel 3 is rotation driven
by exhaust gas supplied into this spiral flow passage 2a. Here, material of the
turbine wheel is generic heat resistant alloy.
[0040]
Moreover, this exhaust turbo supercharger 1 has a compressor housing 12,
inside of which there is formed a spiral flow passage 12a, and a compressor wheel
13 which is provided in a substantially radial direction center of the compressor
housing 12. The compressor wheel 13 is rotation driven to take outside air into the
compressor housing 12 and delivers the outside air that has been taken in, into the
spiral flow passage 12a in the compressor housing 12. The spiral flow passage 12a
of the compressor housing 12 is connected to an air intake system of the internal
combustion engine. Accordingly, the outside air that has been delivered into this
spiral flow passage 12a by the compressor wheel 13, is forcefully delivered to the air
intake system of the internal combustion engine.
18

[0041]
The turbine wheel 3 and the compressor wheel 13 are linked by a turbine shaft
21. A bearing housing 22 is provided between the turbine housing 2 and the
compressor housing 12. In the bearing housing 22, there is provided a bearing 23
that supports the turbine shaft 21, allowing it to rotate about the axis. Moreover, in
the bearing housing 22 there is provided a lubrication mechanism 24 that supplies
lubricating oil to the bearing 23 to lubricate and cool the bearing 23. The bearing
housing 22 is cooled by the lubricating oil supplied by this lubrication mechanism
24. Here, the material of the bearing housing 22 is generally cast iron.
[0042]
In this exhaust turbo supercharger 1, exhaust gas introduced from an exhaust
system of the internal combustion engine into the spiral flow passage 2a in the
turbine housing 2, rotation-drives the turbine wheel 3.
As the turbine wheel 3 is rotation driven in this manner, this driving force is
transmitted to the compressor wheel 13 via the turbine shaft 21, and the compressor
wheel 13 is thereby rotation-driven.
Thus, the compressor wheel takes outside air into the compressor housing 12
and delivers the outside air that has been taken in, into the spiral flow passage 12a
in the compressor housing 12. As a result, the outside air that has been taken into
the compressor housing 12 is forcefully supplied into a combustion chamber of the
internal combustion engine.
[0043]
Furthermore, in this exhaust turbo supercharger 1, as shown in FIG. 2, in the
turbine housing 2 there is provided a variable nozzle mechanism 31 that adjusts the
capacity of the turbine.
The variable nozzle mechanism 31 has nozzle vanes 32 arranged on the inner
circumference side of the spiral flow passage 2a in the turbine housing 2, in a
plurality of positions at equal intervals in the circumferential direction of the turbine
wheel 3. Each of the nozzle vanes 32 is provided on a ring shaped nozzle mount 33
attached to the turbine housing 2, and blade angles thereof (angle with respect to
the radius line of the spiral flow passage 2a) can be respectively adjusted by an
actuator 34.
[0044]
19

By adjusting the blade angle of each of the nozzle vanes 32 with the actuator 33,
the variable nozzle mechanism 31 adjusts the sectional area of the flow passage
from the spiral flow passage to the turbine wheel 3 to adjust the flow speed of
exhaust gas delivered to the turbine wheel 3. By adjusting the flow speed of
exhaust gas delivered to the turbine wheel 3 in this manner, the rotation speed of
the turbine wheel 3 is adjusted, and the volume of air delivered to the air intake
system by the compressor wheel 13 can be adjusted.
[0045]
Here, the turbine housing 2 and the bearing housing 22 are fixed, with the nozzle
mount 33 sandwiched therebetween. That is to say, the turbine housing 2, the
bearing housing 22, and a bolt 48, described later, serve also as fixing devices for
fixing the nozzle mount 33.
In this exhaust turbo supercharger 1, because such a structure for fixing the
nozzle mount 33 described above is employed, separate fixing devices for fixing the
nozzle mount 33 need not be provided, and the number of parts can be reduced,
lowering the production cost.
[0046]
Hereunder, a structure for connecting the turbine housing 2 and the bearing
housing 22 is specifically described, with reference to FIG. 3. In FIG. 3, in order to
facilitate understanding of the connection structure of the turbine housing 2 and the
bearing housing 22, the shapes of the turbine housing 2 and the bearing housing 22
are drawn in simplified forms. Moreover, for the same reason, a supporting
structure for the nozzle mount 33 is omitted from the drawing in FIG. 3.
[0047]
In the bearing housing 22, on the end to be connected with the turbine housing 2,
there is provided a flange section 41 on the outer circumference of the bearing
housing 22.
Moreover, in the turbine housing 2, on the end that connects to the bearing
housing 22, there is provided a concave section 42 that houses the end to be
connected with the turbine housing 2 of the bearing housing 22 along with the flange
section 41.
The internal diameter of the concave section 42 is substantially equal to the outer
diameter of the flange section 41. Furthermore, around the entire circumference of
20

the bottom section outer periphery of the concave section 42, there is provided a
step section 43 that projects in the opening direction (bearing housing 22 side) of
the concave section 42. On this step section 43, there is provided a gasket 44 that
receives the flange section 41 of the bearing housing 22, to seal between the step
section 43 and the bearing housing 22.
Here, the radial direction widths of the step section 43 and the gasket 44 are
narrower than that of the flange section 41. As a result, on the radial direction inside
of the step section 43 and the gasket 44, a space S is formed around the entire
circumference, between the flange section 41, the turbine housing 2 and the bearing
housing 22.
[0048]
In the turbine housing 2, there is provided a plurality of bolt insert holes 46 along
the periphery of the concave section 42. In the present embodiment, the bolt insert
hole 46 is a blind hole.
Inside this bolt insert hole 46 there is provided an internally threaded insert 47
made of heat insulating material. The material of the internally threaded insert 47
may be ceramic having a low level of thermal conductivity for example.
The turbine housing 2 and the bearing housing 22 are detachably fixed by the
internally threaded insert 47 that engages with the bolt 48.
Specifically, the bearing housing 22 is fixed on the turbine housing 2 by the
flange section 41 being clamped between the head section of the bolt 48 and the
step section 43 of the turbine housing 2. A washer may be attached to the head
section of the bolt 48 so that the flange section 41 is clamped between this washer
and the step section 43 of the turbine housing 2.
[0049]
In the exhaust turbo supercharger 1 constructed in this way, heat transmission
between the turbine housing 2 and the bolt 48 is prevented by the internally
threaded insert 47 made from a heat insulating material provided within the bolt
insert hole 46 of the turbine housing 2.
As a result, even if the temperature of the turbine housing 2 rises due to
receiving heat of exhaust gas of the internal combustion engine, since the
temperature rise of the bolt 48 is suppressed, and the thermal expansion amount of
the bolt 48 is reduced, a reduction in the fastening force of the bolt 48 is unlikely to
21

occur.
In this exhaust turbo supercharger 1, since a reduction in the fastening force of
the bolt 48 is unlikely to occur as described above, thereby ensuring the contact
pressure of the gasket 44, the sealing capacity of the gasket 44 can be ensured
without setting the fastening force of the bolt 48 high.
As a result, this exhaust turbo supercharger 1 provides excellent workability in
assembly and disassembly while effectively preventing exhaust gas that has flowed
into between the turbine housing 2 and the bearing housing 22 from leaking to
outside of the device.
[0050]
[Second Embodiment]
Next, a second embodiment of the present invention is described, with reference
to FIG. 4.
An exhaust turbo supercharger 51 according to the present embodiment is an
exhaust turbo supercharger shown in the first embodiment, in which the structure for
connecting the turbine housing 2 and the bearing housing 22 has been modified.
Hereunder, the same reference symbols are assigned to constructions similar to, or
the same as, those in the first embodiment, and detailed descriptions thereof are
omitted.
In this exhaust turbo supercharger 51, a turbine housing 52 is used instead of the
turbo housing 2. The turbine housing 52 is a turbine housing 2 as shown in the first
embodiment, in which, instead of the blind bolt insert hole 46, there is provided a
through hole 56 through which the bolt 48 is inserted.
In this exhaust turbo supercharger 51, by inserting the bolt 48 through the
through hole 56 of the turbine housing 52 and engaging the nut 57 with the tip end
of the bolt 48 that projects from the through hole 56 to clamp the turbine housing 52
and the flange section 41 of the bearing housing 22 between the head section of the
bolt 48 and the nut 57, the turbine housing 52 and the bearing housing 22 are fixed.
[0051]
In the present embodiment, between the through hole 56 and the bolt 48, a gap
is formed. In other words, between the inner surface of the through hole 56 and the
bolt 48, there is formed an air layer A to minimize the contact area between the bolt
48 and the turbine housing 2.
22

[0052]
In the exhaust turbo supercharger 51 constructed in this way, between the inner
surface of the through hole 56 of the turbine housing 2 and the bolt 48, there is
formed the air layer A, and this air layer A prevents heat transmission between the
turbine housing 2 and the bolt 48.
As a result, even if the temperature of the turbine housing 2 rises, the
temperature rise of the bolt 48 is suppressed, and the heat expansion amount of the
bolt 48 is reduced.
Accordingly, in the exhaust turbo supercharger 51 according to the present
embodiment, since a reduction in the fastening force of the bolt 48 is unlikely to
occur so that the contact pressure of the gasket 44 is ensured, the sealing capacity
of the gasket 44 can be ensured without setting the fastening force of the bolt 48
high.
Here, between the inner surface of the through hole 56 and the bolt 48, there
may provided an insert made from a heat insulating material, instead of the air layer
A. Also in this case, since the insert prevents heat transmission between the turbine
housing 2 and the bolt 48, a reduction in the fastening force of the bolt 48 is unlikely
to occur so that the contact pressure of the gasket 44 is ensured, and therefore the
sealing capacity of the gasket 44 can be ensured without setting the fastening force
of the bolt 48 high.
[0053]
[Third Embodiment]
Next, a third embodiment of the present invention is described, with reference to
FIG. 5 and FIG. 6.
An exhaust turbo supercharger 61 according to the present embodiment is
characterized mainly in that a turbine housing 62 is used instead of the turbine
housing 2 in the exhaust turbo supercharger 1 as shown in the first embodiment.
Hereunder, the same reference symbols are assigned to constructions similar to, or
the same as, those in the first embodiment, and detailed descriptions thereof are
omitted.
The turbine housing 62 is a turbine housing 2 as shown in the first embodiment in
which, instead of the bolt insert hole 46, there is provided a screw hole 66 with which
the bolt 48 is engaged. Moreover, in the turbine housing 62, heat radiating fins 67
23

are provided in the vicinity of the screw hole 66. In the present embodiment, as
shown in FIG. 6, in the turbine housing 62, an area in which the screw hole 66 is
formed has a shape that projects toward the outer periphery, and in this area, a
plurality of heat radiating fins 68 are arranged, extending in the axial direction of the
screw hole 66, along the circumferential direction of the screw hole 66 at intervals.
[0054]
In the exhaust turbo supercharger 61 constructed in this way, in the vicinity of the
screw hole 66 of the turbine housing 62, the heat radiating fins 67 are provided to
increase the area of contact with the outside air.
As a result, even if the temperature of the turbine housing 62 rises, in the vicinity
of the screw hole 66 in the turbine housing 62, heat is effectively radiated to the
surrounding area and the temperature rise is suppressed.
As a result, a rise in temperature of the bolt 48 that engages with this screw hole
66 is suppressed, and a thermal expansion amount of the bolt 48 is reduced.
Accordingly, in this exhaust turbo supercharger 61, since a reduction in the
fastening force of the bolt 48 is unlikely to occur, so that the contact pressure of the
gasket 44 is ensured, the sealing capacity of the gasket 44 can be ensured without
setting the fastening force of the bolt 48 high.
[0055]
Here, in this exhaust turbo supercharger 61, a turbine housing 68 shown in FIG.
7 may be used instead of the turbine housing 62. The turbine housing 68 is a
turbine housing 62 in which, instead of the heat radiating fins 67, there is provided a
plurality of heat radiating grooves 69 that extend along the axial direction of the
screw hole 66. FIG. 7 shows an example of providing V grooves as the heat
radiating grooves 69. However, the shape of the heat radiating groove 69 is
arbitrary.
Also in this case, in the vicinity of the screw hole 66 in the turbine housing 68,
heat is effectively radiated to the surrounding area and a rise in temperature can be
suppressed.
As a result, a rise in temperature of the bolt 48 that engages with this screw hole
66 is suppressed, and a thermal expansion amount of the bolt 48 is reduced.
Accordingly, since a reduction in the fastening force of the bolt 48 is unlikely to
occur, so that the contact pressure of the gasket 44 is ensured, the sealing capacity
24

of the gasket 44 can be ensured without setting the fastening force of the bolt 48
high.
[0056]
[Fourth Embodiment]
Next, a fourth embodiment of the present invention is described, with reference
to FIG. 8.
An exhaust turbo supercharger 71 according to the present embodiment is
characterized mainly in that in the exhaust turbo supercharger 1 shown in the first
embodiment, a turbine housing 72 is used instead of the turbine housing 2, and a
bolt 76 is used instead of the bolt 48. Hereunder, the same reference symbols are
assigned to constructions similar to, or the same as, those in the first embodiment,
and detailed descriptions thereof are omitted.
[0057]
The turbine housing 72 is a turbine housing 2 as shown in the first embodiment,
in which there is provided a screw hole 77, instead of the bolt insert hole 46. In the
present embodiment, and on the bottom section of the screw hole 77, there is
provided a through hole 77a that is concentric with the screw hole 77 and has a
diameter smaller than that of the screw hole 77.
The bolt 76 is a bolt 48 as shown in the first embodiment, in which there is
formed a through hole 76a along the axis of the bolt 76.
[0058]
In the exhaust turbo supercharger 71 constructed in this way, in the bolt 76 that
fixes the turbine housing 72 and the bearing housing 22, the through hole 76a is
formed along the axial direction.
Accordingly, the surface area of the bolt 76 is increased and the amount of heat
radiated from the bolt 76 increases, while the bolt 76 is cooled down by outside air
that flows into the through hole 76a.
In the present embodiment, in the area on the bottom section of the screw hole
77 which opposes to the through hole 76a of the bolt 76, the through hole 77a is
provided. Accordingly, since outside air travels through the through hole 76a of the
bolt 76 more easily, the temperature rise in the bolt 76 becomes further unlikely to
occur.
As described above, in this exhaust turbo supercharger 71, even if the
25

temperature of the turbine housing 72 rises, since the temperature rise in the bolt 76
can be suppressed, and the thermal expansion amount of the bolt 76 is reduced, a
decrease in the fastening force of the bolt 76 is unlikely to occur, so that contact
pressure of the gasket 44 can be ensured.
In this exhaust turbo supercharger 71, since a reduction in the fastening force of
the bolt 76 is unlikely to occur as described above, thereby ensuring the contact
pressure of the gasket 44, the sealing capacity of the gasket 44 can be ensured
without setting the fastening force of the bolt 76 high.
In this exhaust turbo supercharger, the screw hole provided in the turbine
housing may be a through hole. In this case too, since outside air travels through
the through hole 76a of the bolt 76 more easily, the temperature rise in the bolt 76
becomes further unlikely to occur.
[0059]
[Fifth Embodiment]
Next, a fifth embodiment of the present invention is described, with reference to
FIG. 9.
An exhaust turbo supercharger 81 according to the present embodiment is
characterized mainly in that in the exhaust turbo supercharger 1 as shown in the first
embodiment, a turbine housing 82 is used instead of the turbine housing 2.
Hereunder, the same reference symbols are assigned to constructions similar to, or
the same as, those in the first embodiment, and detailed descriptions thereof are
omitted.
[0060]
The turbine housing 82 is a turbine housing 2 as shown in the first embodiment,
in which there is provided a screw hole 86, instead of the bolt insert hole 46. In the
present embodiment, the screw hole 86 is a blind hole.
Moreover, on the inner surface of the turbine housing 82, in the area that comes
in contact with exhaust gas, a heat shield layer 88 made from a heat insulating
material is formed.
In the present embodiment, in the turbine housing 82, in the area of the inner
surface of the spiral flow passage 2a and from the spiral flow passage 2a to the
vicinity of the outer periphery of the turbine wheel, the heat shield layer 88 is
formed.
26

As the heat shield layer 88, for example, a heat shield coating film made from a
sprayed film of Co-Ni-Cr-AI-Y alloy or the like may be used.
Furthermore, as the heat shield layer 88, a thin-walled heat shield tube, the outer
shape of which substantially corresponds to the inner surface shape of the spiral
flow passage 2a may be provided. As this heat shield tube, for example, a stainless
steel tube or ceramic tube having a low level of thermal conductivity, may be used.
[0061]
In the exhaust turbo supercharger 81 constructed in this way, the heat shield
layer 88 provided on the inner surface of the turbine housing 82 prevents heat
transmission from the exhaust gas introduced into the turbine housing 82 to the
turbine housing 82.
As a result, even when operating the exhaust turbo supercharger 81, a
temperature increase of the turbine housing 82 can be suppressed, and the thermal
expansion amount of the turbine housing 82 and the bolt 48 that engages with the
turbine housing 82 is reduced. Therefore, a decrease in the fastening force of the
bolt 48 is unlikely to occur, so that the contact pressure of the gasket 44 can be
ensured.
In this exhaust turbo supercharger 81, since a reduction in the fastening force of
the bolt 48 is unlikely to occur as described above, thereby ensuring the contact
pressure of the gasket 44, the sealing capacity of the gasket 44 can be ensured
without setting the fastening force of the bolt 48 high.
Moreover, in this exhaust turbo supercharger 81, since the heat shielding
capacity of the turbine housing 82 is improved, the efficiency of the turbine can be
improved.
Furthermore, in this exhaust gas turbo supercharger 81, since a temperature
increase in the turbine housing 82 can be suppressed, the load on the turbine
housing 82 due to heat stress can be reduced, and the durability of the turbine
housing 82 can be improved.
[0062]
[Sixth Embodiment]
Next, a sixth embodiment of the present invention is described, with reference to
FIG. 10.
An exhaust turbo supercharger 91 according to the present embodiment is
27

characterized mainly in that in the exhaust turbo supercharger 1 as shown in the first
embodiment, a turbine housing 92 is used instead of the turbine housing 2, and a
bearing housing 93 is used instead of the bearing housing 22. Hereunder, the same
reference symbols are assigned to constructions similar to, or the same as, those in
the first embodiment, and detailed descriptions thereof are omitted.
[0063]
The turbine housing 92 is a turbine housing 2 as shown in the first embodiment,
in which the concave section 42 is formed to have diameter smaller than the flange
section 41 of the bearing housing 93, a flange section 92a is provided on an end
that connects to the bearing housing 93, and instead of the bolt insert hole 48, a
through hole 92b that passes through the flange section 92a in the thickness
direction, is provided in the flange section 92a.
In this exhaust turbo supercharger 91, in the turbine housing 92, the gasket 44 is
interposed between: the area between the area in which the through hole 92b is
formed and the concave section 42, and the flange section 41 of the bearing
housing 93.
The bearing housing 93 is one where, in the bearing housing 22, a screw hole
93a is provided in the flange section 41.
[0064]
In the exhaust turbo supercharger 91 constructed in this way, the screw hole 93a
is provided in the bearing housing 93, in which a temperature rise is less likely to
occur compared to the turbine housing 923 that comes in contact with exhaust gas,
and the turbine housing 92 and the bearing housing 93 are connected by the bolt 48
that engages with this screw hole 93a.
In other words, in the bolt 48 that connects the turbine housing 92 and the
bearing housing 93, the thread face, which is the largest area that comes in contact
with other members, is brought in contact with the bearing housing 93, in which a
temperature rise is unlikely to occur.
Therefore, in this exhaust turbo supercharger 91, since the temperature of the
turbine housing 93 is unlikely to be transmitted to the bolt 48 so that the thermal
expansion amount of the bolt 48 is reduced, a decrease in the fastening force of the
bolt 48 is unlikely to occur, so that the contact pressure of the gasket 44 can be
ensured.
28

In this exhaust turbo supercharger 91, since a reduction in the fastening force of
the bolt 48 is unlikely to occur as described above, thereby ensuring the contact
pressure of the gasket 44, the sealing capacity of the gasket 44 can be ensured
without setting the fastening force of the bolt 48 high.
Moreover, in this exhaust turbo supercharger 91, since the head section of the
bolt 48 faces the turbine housing 92 side (end section side of the exhaust turbo
supercharger 91), tools (such as a spanner) can easily enter in the vicinity of the
head section of the bolt 48, enabling easy operation of attaching and detaching the
bolt 48.
[0065]
[Seventh Embodiment]
Next, a seventh embodiment of the present invention is described, with reference
to FIG. 11.
The exhaust turbo supercharger 101 according to the present embodiment is
characterized mainly in that in the exhaust turbo supercharger 1 as shown in the first
embodiment, a turbine housing 102 is used instead of the turbine housing 2, and
between the head section of the bolt 48 and the flange section 41 of the bearing
housing 22, there is provided an elastic member 104 in a state of being compressed
in the axial direction of the bolt 48. Hereunder, the same reference symbols are
assigned to constructions similar to, or the same as, those in the first embodiment,
and detailed descriptions thereof are omitted.
[0066]
The turbine housing 102 is a turbine housing 2 as shown in the first embodiment,
in which there is provided a screw hole 106, instead of the bolt insert hole 46. In the
present embodiment, the screw hole 106 is a blind hole.
In the present embodiment, a conical spring washer is used as the elastic
member 104. The elastic member 104 is not limited to this, and for example, other
types of spring or bush made from rubber or resin having elasticity may be used.
[0067]
In the exhaust turbo supercharger 101 constructed in this way, between the bolt
48 and the bearing housing 22, the elastic member 104 is provided in a state of
being compressed in the axial direction of the bolt 48.
As a result, when a difference occurs between the thermal expansion amounts of
29

the turbine housing 102 and the bolt 104, and the thermal expansion amount of the
bearing housing 22, the elastic member 104 returns from its compressed state by
this difference amount, thereby compensating for the difference between these
thermal expansion amounts. Therefore, a decrease in the fastening force of the bolt
48 is unlikely to occur, so that the contact pressure of the gasket 44 is ensured.
In this exhaust turbo supercharger 101, since a reduction in the fastening force of
the bolt 48 is unlikely to occur as described above, thereby ensuring the contact
pressure of the gasket 44, the sealing capacity of the gasket 44 can be ensured
without setting the fastening force of the bolt 48 high.
[0068]
Here, in the present embodiment, an example of providing the elastic member
104 between the head section of the bolt 48 and the flange section 41 of the bearing
housing 22 is shown. However, as shown in FIG. 12, instead of the elastic member
104, a washer 107 made from a material having a thermal expansion coefficient
higher than that of the bearing housing 22 may be provided. As the material of the
washer 107, for example, Cu (copper) or Cu-base alloy, Al (aluminum) or Al-base
alloy, or Mg (magnesium) based alloy may be used.
In this case, even if there is a difference between the thermal expansion amounts
of the turbine housing 102 and the bolt 48 and the thermal expansion amount of the
bearing housing 22, the difference in their expansion amounts is compensated for
by the expansion amount of the washer 107, so that a decrease in the fastening
force of the bolt 48 is unlikely to occur, and the contact pressure of the gasket 44
can be ensured.
In this exhaust turbo supercharger 101, since a reduction in the fastening force of
the bolt 48 is unlikely to occur as described above, thereby ensuring the contact
pressure of the gasket 44, the sealing capacity of the gasket 44 can be ensured
without setting the fastening force of the bolt 48 high.
[0069]
[Eighth Embodiment]
Next, an eighth embodiment of the present invention is described, with reference
to FIG. 13.
An exhaust turbo supercharger 111 according to the present embodiment is
characterized mainly in that, in the exhaust turbo supercharger 1 as shown in the
30

first embodiment, the turbine housing 102 as shown in the seventh embodiment is
used instead of the turbine housing 2, and a bearing housing 113 is used instead of
the bearing housing 22. Hereunder, the same reference symbols are assigned to
constructions similar to, or the same as, those in the first embodiment, and detailed
descriptions thereof are omitted.
[0070]
The bearing housing 113 is such that a bolt support section 114 that receives the
bolt 48 can elastically deform in the axial direction of the bolt 48.
In the present embodiment, the bearing housing 113 has a slit 116 provided at
least on the outer circumference surface of the area in the flange section 41 that
receives the bolt 48, thereby enabling the bolt support section 114 to be such that
the area that receives the bolt 48 of the flange section 41 can elastically deform in
the axial direction of the bolt 48.
In a state-where the turbine housing 102 and the bearing housing 113 are fixed
by the bolt 48, the bolt support section 114 receives the bolt 48 in a state of being
elastically deformed to the turbine housing 102 side.
[0071]
In the exhaust turbo supercharger 111 constructed in this way, the bolt support
section 114 of the bearing housing 113 receives the bolt 48 in a state of being
elastically deformed to the turbine housing 102 side.
As a result, when a difference occurs between the thermal expansion amounts of
the turbine housing 102 and the bolt 48 and the thermal expansion amount of the
bearing housing 113, the bolt support section 114 returns by that amount in the
direction reducing the amount of its elastic deformation, thereby compensating for
the difference between these thermal expansion amounts. Therefore, a decrease in
the fastening force of the bolt 48 is unlikely to occur, so that the contact pressure of
the gasket 44 is ensured. v
In this exhaust turbo supercharger 111, since a reduction in the fastening force of
the bolt 48 is unlikely to occur as described above, thereby ensuring the contact
pressure of the gasket 44, the sealing capacity of the gasket 44 can be ensured
without setting the fastening force of the bolt 48 high.
[0072]
[Ninth Embodiment]
31

Next, a ninth embodiment of the present invention is described, with reference to
FIG. 14.
An exhaust turbo supercharger 121 according to the present embodiment is
characterized mainly in that, in the exhaust turbo supercharger 1 as shown in the
first embodiment, a turbine housing 122 is used instead of the turbine housing 2,
and a bearing housing 123 is used instead of the bearing housing 22. Hereunder,
the same reference symbols are assigned to constructions similar to, or the same
as, those in the first embodiment, and detailed descriptions thereof are omitted.
[0073]
The turbine housing 122 is a turbine housing 2 as shown in the first embodiment,
in which a screw hole 126 is provided instead of the bolt insert hole 46, and in which
there is provided on the step section 43, a cylindrical male engaging section 127 that
surrounds the turbine shaft 21. In the present embodiment, the screw hole 126 is a
blind hole.
The bearing housing 123 is a bearing housing 22 as shown in the first
embodiment, in which, on the side of the flange section 41 facing the step section
43, there is provided a female engaging section 128 into which the male engaging
section 127 is inserted, the inner circumference surface of which engages with this
male engaging section 127.
The turbine housing 122 and the bearing housing 123 are detachably fixed by the
bolt 48, which engages with the screw hole 126 in a state where the male engaging
section 127 and the female engaging section 128 are engaged with each other.
[0074]
In the exhaust turbo supercharger 121 constructed in this way, when temperature
of the turbine housing 122 rises, the male engaging section 127 provided in the
turbine housing 122 thermal-expands toward the radial direction outside.
On the other hand, since the bearing housing 123 is cooled down by the
lubrication mechanism 24 as mentioned above, the thermal expansion amount of
the female engaging section 128 provided in the bearing housing 123 toward the
radial direction outside is smaller than the thermal expansion amount of the male
engaging section 127 toward the radial direction outside. As a result, when the
temperature of the turbine housing 122 rises, the outer circumference surface of the
male engaging section 127 comes into tight contact with the inner circumference
32

surface of the female engaging section 128, sealing between the turbine housing
122 and the bearing housing 123.
Adhesion between the male engaging section 127 and the female engaging
section 128 becomes stronger as the difference between the thermal expansion
amounts of the male engaging section 127 and the female engaging section 128 (in
other words, the difference between the thermal expansion amounts of the turbine
housing 122 and the bearing housing 123) increases, and the sealing property
between the turbine housing 122 and the bearing housing 123 becomes more
reliable by the amount of this increase.
[0075]
As a result, even if a difference occurs between the thermal expansion amounts
of the turbine housing 122 and the bolt 48, and the bearing housing 123, and the
fastening force of the bolt 48 decreases, leakage of exhaust gas from between the
turbine housing 122 and the bearing housing 123 is prevented.
Therefore, in this exhaust turbo supercharger 121, the sealing capacity of the
gasket 44 can be ensured without setting the fastening force of the bolt 48 higher.
[0076]
Here, the installation position of the male engaging section 127 in the turbine
housing and the installation position of the female engaging section 128 in the
bearing housing are arbitrary.
FIG. 15 shows an exhaust turbo supercharger 131 as an example of an
installation form of the male engaging section 127 and the female engaging section
128.
The exhaust turbo supercharger 131 is an exhaust turbo supercharger 121 in
which a turbine housing 132 is used instead of the turbine housing 122, and a
bearing housing 133 is used instead of the bearing housing 123.
[0077]
The turbine housing 132 is a turbine housing 122 in which the inner diameter
thereof is smaller than the flange section 41 of the bearing housing 133, and the
step section 43 is omitted.
In this exhaust turbo supercharger 131, in the turbine housing 132, the gasket 44
is interposed between: the area between the area in which the screw hole 126 is
formed and the concave section 42, and the flange section 41 of the bearing
33

housing 133.
In this turbine housing 132, the outer periphery thereof constructs the male
engaging section 127.
[0078]
The bearing housing 133 is a bearing housing 123, in which the flange section 41
is made to project from the outer periphery of the turbine housing 132 toward the
radial direction outside, and in which on this flange section 41, there is provided a
through hole 134 into which the bolt 48 is inserted, and the female engaging section
128 is provided in the area on the radial direction outside of the outer periphery of
the turbine housing 132.
[0079]
[Tenth Embodiment]
Next, a tenth embodiment of the present invention is described, with reference to
FIG. 16.
An exhaust turbo supercharger 141 according to the present embodiment is
characterized mainly in that, in the exhaust turbo supercharger 1 as shown in the
first embodiment, a turbine housing 142 is used instead of the turbine housing 2.
Hereunder, the same reference symbols are assigned to constructions similar to, or
the same as, those in the first embodiment, and detailed descriptions thereof are
omitted.
[0080]
Between the turbine housing 142 and the bearing housing 22, toward the radial
direction outside of the turbine shaft 21, there are provided, in the following order, a
narrow section 146 where the distance between the turbine housing 142 and the
bearing housing 22 is short, and an expanded section 147 where the distance
between the turbine housing 142 and the bearing housing 22 is greater than in the
narrow section 146.
In the present embodiment, the turbine housing 142 has the construction of the
turbine housing 2 as shown in the first embodiment, in which a screw hole 144 is
provided instead of the bolt insert hole 46, and in the concave section 42 there is
provided a substantially cylindrical projection section 149, the tip end of which is
inserted into the bearing housing 22.
As a result, the narrow section 146 is formed between the projection section 149
34

and the tip end of the bearing housing 22, and the expanded section 147 is formed
in the area on the radial direction outside of the projection section 149, within the
concave section 42.
[0081]
The narrow section 146 serves as an aperture that reduces the pressure of
exhaust gas flowed in from an insertion passage section for the turbine shaft 21 in
the turbine housing 142, to between the turbine housing 142 and the bearing
housing 22.
The exhaust gas that has passed through the narrow section 146 expands by
flowing into the expanded section 147 reducing the pressure thereof.
As described, in this exhaust turbo supercharger 141, the pressure applied by the
exhaust gas on the gasket 44 can be low. Therefore, even if a difference in the
thermal expansion amounts between the turbine housing 142 and the bolt 48, and
the bearing housing 22 occurs, and the fastening force of the bolt 48 decreases,
leakage of exhaust gas from between the turbine housing 142 and the bearing
housing 22 is prevented.
[0082]
In particular, in the case where the pressure variation of the exhaust gas is
significant, leakage of exhaust gas from between the turbine housing 142 and the
bearing housing 22 can be effectively prevented.
Specifically, as the exhaust gas that has entered between the turbine housing
142 and the bearing housing 22 passes through the narrow section 146, a time
difference occurs in the pressure variance with the exhaust gas within the turbine
housing 142.
As a result, in the expanded section 147, the pressure of the exhaust gas is
averaged and the inner pressure of the expanded section 147 becomes lower than
the peak pressure of the exhaust gas.
Therefore, in this exhaust turbo supercharger 141, the sealing capacity of the
gasket 44 can be ensured without setting the fastening force of the bolt 48 higher.
[0083]
[Eleventh Embodiment]
Next, an eleventh embodiment of the present invention is described, with
reference to FIG. 17.
35

An exhaust turbo supercharger 151 according to the present embodiment is
characterized mainly in that, in the exhaust turbo supercharger 141 as shown in the
tenth embodiment, a turbine housing 152 is used instead of the turbine housing
142. Hereunder, the same reference symbols are assigned to constructions similar
to, or the same as, those in the tenth embodiment, and detailed descriptions thereof
are omitted.
[0084]
The turbine housing 152 is a turbine housing 142 as shown in the tenth
embodiment, in which there is provided a bypass flow passage 154 that continues
from the expanded section 147 to the vicinity of an exhaust gas exit 152a.
Here, since almost all the energy of the exhaust gas that has been introduced
into the turbine housing 152 is consumed in rotation driving the turbine wheel 3, the
pressure of the exhaust gas at the exhaust gas exit 152a of the turbine housing 152
is approximately equal to atmospheric pressure.
Therefore, in the case the where the pressure of the exhaust gas within the
expanded section 147 is greater than the pressure of the exhaust gas in the vicinity
of the exhaust gas exit 152a of the turbine housing 152, the exhaust gas within the
expanded section 147 travels through the bypass flow passage 154 and flows into
the vicinity of the exhaust gas exit 152a of the turbine housing 152, reducing the
inner pressure of the expanded section 147.
Therefore, in this exhaust turbo supercharger 151, the pressure applied by the
exhaust gas to the gasket 44 becomes low, and the sealing capacity of the gasket
44 can be ensured.
36

CLAIMS
1. An exhaust turbo supercharger having:
a turbine housing, into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a bolt insert hole is formed in said turbine housing,
an internal thread insert made from a heat insulating material is provided in said
bolt insert hole, and
said turbine housing and said bearing housing are detachably fixed by a bolt that
engages with said internal thread insert.
2. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a through hole is formed in said turbine housing,
37

said turbine housing and said bearing housing are detachably fixed by a bolt
inserted into said through hole, and a nut that engages with said bolt;
and an insert made from a heat insulating material, or an air layer, is provided
between an inner surface of said through hole and said bolt.
3. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a screw hole is formed in said turbine housing,
heat radiating fins or heat radiating grooves are formed in the vicinity of said
screw hole,
and said turbine housing and said bearing housing are detachably fixed by a bolt
that engages with said screw hole.
4. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
38

a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein there is formed a screw hole in said turbine housing;
said turbine housing and said bearing housing are detachably fixed by a bolt that
engages with said screw hole;
and a through hole is provided in said bolt along the axis of said bolt.
5. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a screw hole is formed in said turbine housing;
said turbine housing and said bearing housing are detachably fixed by a bolt that
engages with said screw hole;
and on an inner surface of said turbine housing in an area in contact with said
exhaust gas, a heat shield layer is formed.
6. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
39

a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a screw hole is formed in said bearing housing,
and said turbine housing and said bearing housing are detachably fixed by a bolt
that engages with said screw hole.
7. An exhaust turbo supercharger having:
a turbine housing, into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a screw hole is formed in said turbine housing;
said turbine housing and said bearing housing are detachably fixed by a bolt that
engages with said screw hole;
and between a head section of said bolt and said bearing housing there is
provided an elastic member in a state of being compressed in the axial direction of
said bolt.
8. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
40

which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a screw hole is formed in said turbine housing,
said turbine housing and said bearing housing are detachably fixed by a bolt that
engages with said screw hole,
and in said bearing housing, a bolt support section that receives said bolt is able
to elastically deform in the axial direction of said bolt, and said bolt support section
receives said bolt in a state of being elastically deformed to said turbine housing
side.
9. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a screw hole is formed in said turbine housing,
in said turbine housing a cylindrical male engaging section that surrounds said
turbine shaft is provided,
in said bearing housing there is provided a female engaging section into which
said male engaging section is inserted, an inner surface of which is fitted together
with said male engaging section,
and said turbine housing and said bearing housing are detachably fixed by a bolt
41

that engages with said screw hole, in a state where said male engaging section and
said female engaging section are fitted together.
10. An exhaust turbo supercharger having:
a turbine housing into which exhaust gas from an internal combustion engine is
introduced;
a turbine wheel which is provided within said turbine housing and which is
rotation-driven by said exhaust gas;
a turbine shaft, one end of which is inserted into said turbine housing, and to
which said turbine wheel is attached;
a bearing which supports said turbine shaft;
a bearing housing which is connected to said turbine housing and inside of which
said bearing is housed; and
a gasket which seals, in an area outside in the radial direction of said turbine
shaft, between said turbine housing and said bearing housing;
wherein a screw hole is formed in said turbine housing,
and between said turbine housing and said bearing housing, there are provided
in the following order toward the radial direction outside of said turbine shaft:
a narrow section in which a distance between said turbine housing and said
bearing housing is short;
and an expanded section in which a distance between said turbine housing and
said bearing housing is greater than that in said narrow section;
and said turbine housing and said bearing housing are detachably fixed by a bolt
that engages with said screw hole.
11. An exhaust turbo supercharger according to claim 10, wherein in said turbine
housing, there is provided a bypass flow passage that continues from said expanded
section to the vicinity of an exit of said exhaust gas.
42

An exhaust turbo supercharger is provided that is able to effectively prevent exhaust gas that has flowed into between a turbine housing and a bearing housing from leaking to outside of the device, while allowing an excellent level of workability in assembly and disassembly. Included is a turbine housing, into which exhaust gas from an internal combustion engine is introduced; a turbine wheel which is provided
within the turbine housing and which is rotation-driven by the exhaust gas; a turbine shaft, one end of which is inserted into the turbine housing, and to which the turbine wheel is attached; a bearing which supports the turbine shaft; and a bearing housing which is connected to the turbine housing and inside of which the bearing is housed. A bolt insert hole is formed in the turbine housing, and an internal thread
insert made from a heat insulating material is provided in the bolt insert hole, and the turbine housing and the bearing housing are fixed by a bolt that engages with the internal thread insert.