WO2022208839A1

WO2022208839A1 - Supercharger

Info

Publication number: WO2022208839A1
Application number: PCT/JP2021/014145
Authority: WO
Inventors: 哲也松尾; 幸博岩佐; 太陽白川
Original assignee: 三菱重工マリンマシナリ株式会社
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2022-10-06
Also published as: KR20230131946A; CN117083451A

Abstract

Provided is a supercharger including: a rotor that includes a compressor impeller; a bearing that supports the rotor in a rotatable manner; and a bearing base that accommodates the bearing. The bearing base has: a cooling space that is formed on a back side of the compressor impeller; a bearing accommodation space that accommodates the bearing; a lubricating-oil flow path that allows the cooling space and the bearing accommodation space to communicate with each other, in order to supply lubricating oil from the cooling space to the bearing accommodation space; and a lubricating-oil supply port that is formed in an outer surface of the bearing base and that communicates with the cooling space. The supercharger further includes a lubricating-oil supply line that is configured to supply the lubricating oil from the outside of the supercharger to the cooling space via the lubricating-oil supply port.

Description

supercharger

The present disclosure relates to a supercharger with a centrifugal compressor.

An internal combustion engine (for example, an engine) is sometimes equipped with a supercharger to improve its output. The turbocharger rotates a compressor impeller (hereinafter referred to as impeller) by rotating the turbine rotor with the exhaust gas from the internal combustion engine, and compresses the gas (for example, combustion air) supplied to the internal combustion engine. There is an exhaust turbine type turbocharger configured for As a compressor for an exhaust turbine supercharger, a centrifugal compressor is known that sends out the gas sent to the impeller outward in a radial direction perpendicular to the rotation axis of the impeller.

In recent years, as the output of internal combustion engines has increased, there has been a demand for a centrifugal compressor with a higher pressure ratio. In order to increase the pressure ratio of the centrifugal compressor, the rotation peripheral speed of the impeller is increased. If the rotating peripheral speed of the impeller is increased, the stress generated inside the impeller due to the centrifugal force generated by the rotation increases. In addition, if the rotational peripheral speed of the impeller is increased, the temperature of the gas compressed by the impeller increases, and this high-temperature gas leaks into the space facing the back surface of the impeller and heats the impeller from the back surface. , the impeller becomes hot. The impeller exposed to such high temperature and high pressure may have a reduced high-temperature creep strength and a shortened service life.

JP 2014-111905 A Japanese Patent No. 6246847 Japanese Patent No. 3606293

Conventionally, the impeller was cooled by supplying cooling air to the space facing the back of the compressor (see Patent Document 1, for example). Combustion air that has passed through an intercooler after being compressed by a centrifugal compressor has sometimes been used as the cooling air. In this case, part of the combustion air compressed by the centrifugal compressor is not supplied to the internal combustion engine, which may lead to a decrease in efficiency of the entire internal combustion engine system including the internal combustion engine.

In addition, by supplying lubricating oil to the space formed on the back side of the impeller in the casing that houses the impeller, the gas in the space facing the back side of the impeller is cooled, thereby indirectly cooling the impeller. was also performed (see, for example, Patent Documents 2 and 3). The lubricating oil supplied to the space formed on the back side of the impeller is discharged to the outside of the casing as it is.

In view of the circumstances described above, an object of at least one embodiment of the present disclosure is to provide a supercharger capable of cooling the back surface of the compressor impeller and improving the efficiency of the internal combustion engine system.

The turbocharger according to the present disclosure is
A turbocharger comprising a rotor including a compressor impeller, a bearing that rotatably supports the rotor, and a bearing base that houses the bearing,
The bearing stand is
a cooling space formed on the back side of the compressor impeller;
a bearing housing space for housing the bearing;
a lubricating oil flow path communicating between the cooling space and the bearing housing space for sending lubricating oil from the cooling space to the bearing housing space;
a lubricating oil supply port formed on the outer surface of the housing, the lubricating oil supply port communicating with the cooling space;
The turbocharger is
It further comprises a lubricating oil supply line configured to send lubricating oil from the outside of the supercharger to the cooling space through the lubricating oil supply port.

According to at least one embodiment of the present disclosure, a turbocharger is provided that can cool the back surface of the compressor impeller and improve the efficiency of the internal combustion engine system.

1 is an explanatory diagram for explaining the configuration of an internal combustion engine system including a supercharger according to an embodiment of the present disclosure; FIG. FIG. 2 is a schematic cross-sectional view of the turbocharger showing an A section extracted from the turbocharger shown in FIG. 1 ; 1 is a schematic cross-sectional view of a turbocharger according to an embodiment of the present disclosure, showing a portion corresponding to a section A of the turbocharger shown in FIG. 1; FIG. FIG. 3 is an explanatory diagram for explaining a lubricating oil system in the supercharger shown in FIG. 2; FIG. 3 is an explanatory diagram for explaining a modification of the lubricating oil system in the supercharger shown in FIG. 2; FIG. 4 is an explanatory diagram for explaining a lubricating oil system in the turbocharger shown in FIG. 3;

Several embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as the embodiment or shown in the drawings are not meant to limit the scope of the present disclosure, but are merely illustrative examples. do not have.
For example, expressions denoting relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" are strictly not only represents such an arrangement, but also represents a state of relative displacement with a tolerance or an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous", which express that things are in the same state, not only express the state of being strictly equal, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, expressions that express shapes such as squares and cylinders do not only represent shapes such as squares and cylinders in a geometrically strict sense, but also include irregularities and chamfers to the extent that the same effect can be obtained. The shape including the part etc. shall also be represented.
On the other hand, the expressions "comprising", "including", or "having" one component are not exclusive expressions excluding the presence of other components.
In addition, the same code|symbol may be attached|subjected about the same structure and description may be abbreviate|omitted.

(turbocharger, internal combustion engine system)
FIG. 1 is an explanatory diagram for explaining the configuration of an internal combustion engine system including a turbocharger according to one embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view of the turbocharger showing an A portion extracted from the turbocharger shown in FIG. FIG. 3 is a schematic cross-sectional view of a turbocharger according to an embodiment of the present disclosure, and is a schematic cross-sectional view of the turbocharger showing a portion corresponding to part A of the turbocharger shown in FIG. be. In each of FIG. 1 and FIGS. 2 to 6, which will be described later, the up-down direction in the drawing corresponds to the vertical direction, and the upper side in the drawing corresponds to the upper direction in the vertical direction.
A supercharger 10 according to some embodiments is configured to rotatably support a rotor 3 including a compressor impeller 2 (hereinafter abbreviated as the impeller 2) and the rotor 3, as shown in FIG. and a bearing pedestal 7 configured to accommodate the bearing 4 . The turbocharger 10 is applied to a marine engine turbocharger, a land-use generator engine turbocharger, and the like. The turbocharger 10 can also be applied to a turbocharger for automobiles, which is smaller than a turbocharger for marine engines.

Hereinafter, as shown in FIG. 1, for example, the direction in which the axis CA of the supercharger 10 extends is defined as the axial direction X, and the direction orthogonal to the axis CA is defined as the radial direction Y. The side of the axial direction X where the intake port 61 is located with respect to the impeller 2 (left side in the drawing) is defined as the front side XF, and the side opposite to the intake port 61 side (right side in the drawing) is defined as the rear side XR.

In the illustrated embodiment, the rotor 3 comprises a rotating shaft 31 having a longitudinal direction along the axial direction X, an impeller 2 mechanically coupled to the front XF end 311 of the rotating shaft 31 , the rotating shaft 31 a turbine 32 mechanically coupled to the aft XR end 312 of the . The impeller 2 is arranged coaxially with the turbine 32 . The impeller 2, as shown in FIG. 1, is provided in a supply line 12 that supplies gas (eg, combustion gas such as air) to an internal combustion engine 11 (eg, engine). The turbine 32 is provided in an exhaust line 13 for exhausting exhaust gas from the internal combustion engine 11 . The internal combustion engine system 1 includes a supercharger 10 , an internal combustion engine 11 , a supply line 12 , an exhaust line 13 and an intercooler 14 .

In the illustrated embodiment, the supercharger 10 includes a compressor housing 6 configured to rotatably house the impeller 2 and a turbine housing 8 configured to rotatably house the turbine 32 . Prepare more. The bearing stand 7 is arranged between the compressor housing 6 and the turbine housing 8 and is mechanically connected to the compressor housing 6 and the turbine housing 8 by fastening members such as bolts.

The turbocharger 10 rotates the turbine 32 by exhaust gas introduced into the turbine housing 8 through the exhaust line 13 from the internal combustion engine 11 . Since the impeller 2 is mechanically connected to the turbine 32 via the rotating shaft 31 , it rotates together with the rotation of the turbine 32 . By rotating the impeller 2 , the supercharger 10 compresses the gas introduced into the compressor housing 6 through the supply line 12 and sends the compressed gas to the internal combustion engine 11 . The gas compressed by the impeller 2 is supplied to the internal combustion engine 11 after being cooled by an intercooler 14 provided between the impeller 2 and the internal combustion engine 11 in the supply line 12 .

The impeller 2 has a hub 21 and a plurality of impeller blades 23 provided on the outer surface 22 of the hub 21 . The hub 21 is mechanically fixed to the front XF end 311 of the rotating shaft 31 . Therefore, the hub 21 and the plurality of impeller blades 23 are rotatable around the axis CA of the supercharger 10 integrally with the rotary shaft 31 . In the illustrated embodiment, the impeller 2 consists of a centrifugal impeller configured to direct the gas delivered from the front side XF in the axial direction X outward in the radial direction Y. As shown in FIG.

The compressor housing 6 has an intake port 61 for introducing gas from the outside of the compressor housing 6, an exhaust port (not shown) for discharging the gas that has passed through the impeller to the outside of the compressor housing and sending it to the internal combustion engine, is formed. The turbine housing 8 includes an exhaust gas introduction port (not shown) for introducing exhaust gas into the turbine housing 8, an exhaust gas discharge port 81 for discharging the exhaust gas generated by rotating the turbine 32 to the outside of the turbine housing 8, is formed.

The compressor housing 6 includes an air intake introduction portion 620 forming an air intake passage 62 for introducing gas introduced into the compressor housing 6 from the air intake port 61 into the impeller 2, A shroud portion 630 having a shroud surface 63 curved in a convex shape so as to face each other, and a scroll portion 640 forming a scroll flow path 64 for guiding the gas that has passed through the impeller 2 to the outside of the compressor housing 6 are provided. Each of the intake channel 62 and the scroll channel 64 is formed inside the compressor housing 6 .

In the illustrated embodiment, the compressor housing 6 includes an impeller chamber 65 that rotatably houses the impeller 2 and a diffuser passage 66 that guides gas from the impeller 2 to the scroll passage 64 in combination with the bearing pedestal 7 . and are formed. The shroud surface 63 described above defines the front XF portion of the impeller chamber 65 . As shown in FIGS. 1 to 3, when the impeller 2 is housed in the impeller chamber 65, there is a gap between the back surface 24 of the impeller 2 (surface on the rear side XR side) and the end surface 71 on the front side XF side of the bearing stand 7. A gap 65A is formed in .

Hereinafter, the upstream side in the flow direction of the gas flowing inside the compressor housing 6 may be simply referred to as the "upstream side", and the downstream side in the flow direction of the gas may simply be referred to as the "downstream side".

As shown in FIG. 1, the intake passage 62 extends along the axial direction X. The intake passage 62 communicates with the intake port 61 located on the front side XF (upstream side) and the inlet side of the impeller chamber 65 located on the rear side XR (downstream side). The diffuser flow path 66 extends along a direction intersecting (for example, perpendicular to) the axis CA of the supercharger 10 . The diffuser channel 66 communicates with the outlet side of the impeller chamber 65 located upstream and the scroll channel 64 located downstream. The scroll flow path 64 has a spiral shape surrounding the periphery of the impeller 2 (outside in the radial direction Y). The scroll flow path 64 communicates with a diffuser flow path 66 located upstream and a discharge port (not shown) located downstream.

The gas introduced into the compressor housing 6 from the intake port 61 flows through the intake passage 62 along the axial direction X to the rear side XR, and then is sent to the impeller 2 and compressed by the impeller 2 . The gas compressed by the impeller 2 flows outward in the radial direction through the diffuser flow path 66 and the scroll flow path 64 in this order, and is then discharged to the outside of the compressor housing 6 from a discharge port (not shown). Part of the gas compressed by impeller 2 flows into gap 65A described above.

As shown in FIGS. 1 to 3, inside the bearing stand 7 are a cooling space 72 in which lubricating oil flows as a cooling medium on the back surface 24 side of the impeller 2, and a bearing housing space for housing the bearing 4 described above. 73 and are formed. The cooling space 72 is formed on the front side XF of the bearing housing space 73, in other words, between the gap 65A and the bearing housing space 73 in the axial direction X. As shown in FIG.
In the illustrated embodiment, the cooling space 72 has a distance D1 to the gap 65A that is shorter than a distance D2 to the bearing accommodation space 73, as shown in FIG. The cooling space 72 extends along the circumferential direction around the axis CA of the supercharger 10 and is formed outside the bearing housing space 73 in the radial direction Y. As shown in FIG. In addition, the cooling space 72 has an outer peripheral end 721 located outside the trailing edge 25 of the impeller blades 23 in the radial direction Y, and an inner peripheral end 722 of the cooling space 72 located radially Y relative to the trailing edge 25 of the impeller blades 23 . located inside. The illustrated embodiment shows an example of a lubricating oil system in the turbocharger 10. The cooling space 72, the bearing housing space 73, and a lubricating oil supply passage 750, which will be described later, constitute the lubricating oil system. and the lubricating oil flow path 76 are not limited to the illustrated configuration.

The bearing base 7 has at least one lubricating oil supply port 75 formed in an outer surface 74 exposed to the outside and communicating with the cooling space 72, the cooling space 72 and the bearing. At least one lubricating oil flow path 76 communicating with the housing space 73 is formed. At least one lubricating oil supply channel 750 for feeding lubricating oil to the cooling space 72 from the outside is formed inside the bearing stand 7 . A lubricating oil supply port 75 is formed on one end side of the lubricating oil supply channel 750 , and a communication port 723 communicating with the cooling space 72 is formed on the other end side of the lubricating oil supply channel 750 . The lubricating oil flow path 76 has an inlet opening 761 communicating with the cooling space 72 at one end thereof, and an outlet opening 762 communicating with the bearing housing space 73 at the other end thereof. The "outer surface 74 exposed to the outside" includes a surface accessible from the outside of the bearing base 7 in the turbocharger 10 after assembly, and the lubricating oil supply port 75 is formed in such a surface. may Also, in the illustrated example, the lubricating oil is supplied into the bearing pedestal 7 from above the bearing pedestal 7 , but it may be supplied into the bearing pedestal 7 from below the bearing pedestal 7 .

As shown in FIG. 1 , the turbocharger 10 further includes a lubricating oil supply line 9 configured to send lubricating oil from the outside of the bearing stand 7 to the cooling space 72 through a lubricating oil supply port 75 . The lubricating oil supply line 9 includes at least a lubricating oil pipe 91 having one end connected to the lubricating oil supply port 75 and a lubricating oil pump 92 provided at the other end of the lubricating oil pipe 91 . The lubricating oil pump 92 is configured to generate power for pumping the lubricating oil by electric power. By driving the lubricating oil pump 92 , the lubricating oil is sent from the other end side of the lubricating oil pipe 91 to the one end side, and then sent to the cooling space 72 through the lubricating oil supply port 75 . The lubricating oil sent to the cooling space 72 cools the region 71A including the end surface 71 on the front side of the cooling space 72 in the bearing stand 7, thereby indirectly cooling the gas existing in the gap 65A. be. By cooling the gas present in the gap 65A, heat input from the gap 65A to the back surface 24 of the impeller 2 can be suppressed, thereby suppressing an increase in the metal temperature of the impeller 2 when the turbocharger 10 is driven.

The lubricating oil in the cooling space 72 is sent to the bearing housing space 73 through the lubricating oil flow path 76 by the lubricating oil pump 92 and supplied to the bearings 4 housed in the bearing housing space 73 . In the illustrated embodiment, the outlet opening 762 of the lubricating oil flow path 76 is formed in an inner wall surface 731A of the inner wall surface 731 that defines the bearing housing space 73 and faces the outer surface 41 of the bearing 4 . Lubricating oil is supplied to the bearing 4 from the outer surface 41 side of the bearing 4 . Here, the lubricating oil in the cooling space 72 receives heat from the gas existing in the gap 65A, and its temperature rises, and its viscosity is lower than before the temperature rise. As a result, since the lubricating oil with reduced viscosity is supplied to the bearings 4 , the friction caused by the viscous resistance of the lubricating oil can be reduced, so that the mechanical loss of the bearings 4 can be suppressed.

As shown in FIGS. 1 to 3, the supercharger 10 according to some embodiments includes the impeller 2 described above, the bearing stand 7 described above, and the lubricating oil supply line 9 described above. The bearing base 7 is formed with the cooling space 72 , the bearing housing space 73 , the lubricating oil supply port 75 and the lubricating oil flow path 76 described above.

According to the above configuration, by cooling the back surface 24 of the impeller 2 with the lubricating oil sent to the cooling space 72 through the lubricating oil supply port 75 by the lubricating oil supply line 9, the temperature rise of the impeller 2 can be suppressed. . By suppressing the temperature rise of the impeller 2, the centrifugal compressor of the supercharger 10 can be operated at a high pressure ratio.

Further, according to the above configuration, the lubricating oil whose temperature has been raised by receiving heat in the cooling space 72 flows through the lubricating oil flow path 76 into the bearing housing space 73 that houses the bearing 4 . Since the bearing 4 is supplied with the lubricating oil whose viscosity has decreased due to the temperature rise in the cooling space 72, the mechanical efficiency of the bearing 4 can be improved, and the internal combustion engine system 1 including the turbocharger 10 can be improved. Efficiency can be improved.

In some embodiments, the lubricating oil supply line 9 discussed above is a lubricating oil recovery line configured to send the lubricating oil sent to the bearings 4 discussed above to a lubricating oil pump 92, as shown in FIG. 93 is further included. In this case, since the internal combustion engine system 1 is provided with the lubricating oil supply line 9 including the lubricating oil recovery line 93 , the lubricating oil can be circulated through the lubricating oil supply line 9 .

In some embodiments, the lubricating oil supply line 9 described above, as shown in FIG. Further includes cooler 94 . The oil cooler 94 is configured to cool lubricating oil passing through the oil cooler 94 . The lubricating oil receives heat when circulating in the bearing stand 7 and raises its temperature. If the temperature of the lubricating oil sent to the cooling space 72 becomes too high, the cooling performance of the lubricating oil may deteriorate. According to the above configuration, by cooling the lubricating oil sent from the lubricating oil pipe 91 to the cooling space 72 by the oil cooler 94, it is possible to suppress the deterioration of the cooling performance of the lubricating oil, so that the lubricating oil in the cooling space 72 allows adequate cooling of the rear surface 24 of the impeller 2 by .

Generally, the internal combustion engine system 1 including the turbocharger 10 and the internal combustion engine 11 has a lubricating oil circulation system that circulates lubricating oil. For the oil cooler 94 described above, the oil cooler used in the lubricating oil circulation system may be used. In this case, proper cooling of the back surface 24 of the impeller 2 can be achieved without significant modifications to the internal combustion engine system 1 .

FIG. 4 is an explanatory diagram for explaining a lubricating oil system in the supercharger shown in FIG. 2. FIG. FIG. 5 is an explanatory diagram for explaining a modification of the lubricating oil system in the supercharger shown in FIG. FIGS. 4, 5, and 6, which will be described later, schematically show the lubricating oil system in the supercharger as seen from the front side in the axial direction. A lubricating oil system in the supercharger 10 includes a cooling space 72, a bearing housing space 73, a lubricating oil flow path 76, and the like.
In some embodiments, the cooling space 72 described above is formed in an annular shape extending along the circumferential direction of the supercharger 10, as shown in FIGS. The inner wall surface 720 defining the cooling space 72 is formed with at least one communication port 723 and at least one inlet opening 761 described above.

For example, in the embodiment shown in FIG. 4, at least one communication port 723 includes a communication port 723A communicating with one of two lubricating oil supply ports 75 formed in the bearing base 7, and two lubricating oil supply ports 723A. and a communication port 723B communicating with the other of the ports 75. The two

communication ports

723A and 723B are formed in the upper part of the inner wall surface 720 and are formed at positions apart from each other in the circumferential direction of the supercharger 10 . One communication port 723A is provided on one side (for example, the left side in the figure) in the width direction (the direction orthogonal to the direction in which the axis CA of the supercharger 10 extends and the vertical direction), and the other communication port 723B is provided on the other side in the width direction (for example, the right side in the figure). Also, an inlet opening 761 is formed in the lower portion of the inner wall surface 720 .

The lubricating oil that has flowed into the cooling space 72 from one communication port 723A flows downward on one side of the cooling space 72 in the width direction, and then flows out from the inlet opening 761 into the lubricating oil flow path 76 . On the other hand, the lubricating oil that has flowed into the cooling space 72 from the other communication port 723B flows downward on the other side of the cooling space 72 in the width direction, and then enters the lubricating oil flow path 76 from the inlet opening 761. leak. In this case, the lubricating oil that fills substantially the entire circumference of the annular cooling space 72 in the circumferential direction can cool the gas present in the gap 65A.

Also, in the embodiment shown in FIG. 5, the at least one communication port 723 includes one communication port 723C formed in the upper portion of the inner wall surface 720. Also, an inlet opening 761 is formed in the upper portion of the inner wall surface 720 . The communication port 723</b>C and the inlet opening 761 are formed at positions separated from each other in the circumferential direction of the supercharger 10 . The communication port 723C is provided on one side in the width direction (for example, the left side in the drawing), and the inlet opening 761 is provided on the other side in the width direction (for example, the right side in the drawing). The bearing pedestal 7 has a partition wall 79 that closes part of the cooling space 72 in the circumferential direction. For example, the partition wall 79 is provided in the upper part of the cooling space 72 on the side where the interval between the communication port 723C and the inlet opening 761 in the circumferential direction of the cooling space 72 is narrow. The lubricating oil that has flowed into the cooling space 72 from the communication port 723C flows along the circumferential direction opposite to the side where the partition wall 79 is arranged (the lower part of the cooling space 72), and then flows through the inlet opening 761. It flows out to the lubricating oil flow path 76 .

According to the above configuration, by sending the lubricating oil to the cooling space 72 formed in an annular shape, the lubricating oil is filled substantially over the entire circumference of the cooling space 72 in the circumferential direction. Appropriate cooling can be provided all around in the direction. In this case, the impeller 2 can be cooled more efficiently than when the cooling space 72 is partially formed in the circumferential direction.

FIG. 6 is an explanatory diagram for explaining a lubricating oil system in the turbocharger shown in FIG. 3. FIG.
In some embodiments, the cooling space 72 described above is located above the axis CA of the supercharger 10, as shown in FIGS.
For example, in the illustrated embodiment, as shown in FIG. 6, the cooling space 72 is curved in an upwardly convex arc. The cooling space 72 is not formed below the axis CA of the supercharger 10 . At least one communication port 723 includes a communication port 723D formed in the upper portion of the inner wall surface 720. FIG. Inlet openings 761 of the two lubricating oil flow paths 76 are respectively formed below the communication port 723D of the inner wall surface 720 . The two inlet openings 761 are respectively formed at the tip (lower end) of the cooling space 72 curved in an arc shape. One of the two inlet openings 761 is provided on one side in the width direction (for example, the right side in the drawing), and the other of the two inlet openings 761 is provided on the other side in the width direction (for example, in the drawing). left). The two lubricating oil flow paths 76 may be provided completely independently, or may be joined in the middle.

Also, in the illustrated embodiment, as shown in FIG. It slopes downward toward the exit opening 762 .

As described above, the lubricating oil whose temperature has risen in the cooling space 72 has a lower viscosity, and thus its fluidity is improved. According to the above configuration, since the cooling space 72 is positioned above the axis CA of the supercharger 10, the lubricating oil flows through the lubricating oil passage 76 into the region including the axis CA of the supercharger 10. It can easily flow into the formed bearing housing space 73 by its own weight. Moreover, according to the above configuration, the flow distance of the lubricating oil in the cooling space 72 can be shortened compared to the case where the cooling space 72 is formed in an annular shape. As described above, the capacity of the lubricating oil pump 92 for feeding the lubricating oil can be reduced, so the manufacturing cost of the internal combustion engine system 1 can be reduced. In addition, since the impeller 2 rotates when the supercharger 10 is driven, the cooling space 72 formed in a part of the circumferential direction covers a part of the gap 65A facing the back surface 24 of the impeller 2 in the circumferential direction. By cooling, the back surface 24 of the impeller 2 can be cooled over the entire circumference.

The present disclosure is not limited to the above-described embodiments, and includes modifications of the above-described embodiments and modes in which these forms are combined as appropriate.

The contents described in the several embodiments described above can be understood, for example, as follows.

1) A turbocharger (10) according to at least one embodiment of the present disclosure,
A turbocharger comprising a rotor (3) including a compressor impeller (2), a bearing (4) rotatably supporting the rotor (3), and a bearing stand (7) accommodating the bearing (4). (10),
The bearing pedestal (7) is
a cooling space (72) formed on the back surface (24) side of the compressor impeller (2);
a bearing housing space (73) for housing the bearing (4);
a lubricating oil flow path (76) communicating the cooling space (72) and the bearing housing space (73) to send lubricating oil from the cooling space (72) to the bearing housing space (73);
a lubricating oil supply port (75) formed in the outer surface (74) of the bearing stand (7), the lubricating oil supply port (75) communicating with the cooling space (72);
The supercharger (10) is
It further comprises a lubricating oil supply line (9) configured to send lubricating oil from the outside of the supercharger (10) to the cooling space (72) through the lubricating oil supply port (75).

According to the above configuration 1), the back surface (24) of the impeller (2) is cooled by the lubricating oil sent to the cooling space (72) through the lubricating oil supply port (75) by the lubricating oil supply line (9). By doing so, the temperature rise of the impeller (2) can be suppressed. By suppressing the temperature rise of the impeller (2), the centrifugal compressor of the turbocharger (10) can be operated at a high pressure ratio.

Further, according to the configuration of 1) above, the lubricating oil whose temperature has been increased by receiving heat in the cooling space (72) passes through the lubricating oil flow path (76) to the bearing housing space (73) in which the bearing (4) is housed. flow to Since the bearing (4) is supplied with lubricating oil whose viscosity has decreased due to an increase in temperature in the cooling space (72), the mechanical efficiency of the bearing (4) can be improved, which in turn leads to the supercharger (10). ), the efficiency of the internal combustion engine system (1) can be improved.

2) In some embodiments, the turbocharger (10) of 1) above,
The cooling space (72) is formed in an annular shape extending along the circumferential direction of the rotor (3).

According to the above configuration 2), by sending lubricating oil to the cooling space (72) formed in an annular shape, the cooling space (72) is filled with the lubricating oil almost all around in the circumferential direction. The rear surface (24) of (2) can be appropriately cooled over the entire circumference. In this case, the impeller (2) can be cooled more efficiently than when the cooling space (72) is partially formed in the circumferential direction.

3) In some embodiments, the turbocharger (10) of 1) above,
The cooling space (72) is located above the axis (CA) of the supercharger (10).

As described above, the lubricating oil whose temperature has risen in the cooling space (72) has a lower viscosity, and thus its fluidity is improved. According to the configuration of 3) above, since the cooling space (72) is positioned above the axis (CA) of the supercharger (10), the lubricating oil flows through the lubricating oil passage (76). It can easily flow into the bearing housing space (73) formed in the area including the axis (CA) of the feeder (10) by its own weight. Moreover, according to the configuration of 3) above, the flow distance of the lubricating oil in the cooling space (72) can be shortened compared to the case where the cooling space (72) is formed in an annular shape. As described above, the capacity of the lubricating oil pump (92) for sending lubricating oil can be reduced, so that the manufacturing cost of the internal combustion engine system (1) can be reduced.

1 Internal Combustion Engine System 2 Impeller 21 Hub 22 Outer Surface 23 Impeller Blades 231 Tip 24 Back Side 25 Trailing Edge 3 Rotor 31 Rotating Shaft 311 Front End 312 Rear End 32 Turbine 4 Bearing 41 Outer Surface 6 Compressor Housing 61 Air Inlet 62 intake passage 620 intake introduction portion 63 shroud surface 630 shroud portion 64 scroll passage 640 scroll portion 65 impeller chamber 65A gap 66 diffuser passage 7 bearing stand 71 end surface 71A region 72 cooling space 720 inner wall surface 721 outer peripheral end 722 inner

peripheral end

723, 723A to 723D Communication port 73 Bearing housing space 731, 731A Inner wall surface 74 Outer surface 75 Lubricant oil supply port 750 Lubricant oil supply channel 76 Lubricant channel 761 Inlet opening 762 Outlet opening 79 Partition wall 8 Turbine housing 81 Exhaust gas discharge port 9 Lubricating oil supply line 91 Lubricating oil pipe 92 Lubricating oil pump 93 Lubricating oil recovery line 94 Oil cooler 10 Turbocharger 11 Internal combustion engine 12 Supply line 13 Discharge line 14 Intercooler CA Axis X Axial direction XF (Axial) front XR (Axial) rear Y radial direction

Claims

A turbocharger comprising a rotor including a compressor impeller, a bearing that rotatably supports the rotor, and a bearing base that houses the bearing,
The bearing stand is
a cooling space formed on the back side of the compressor impeller;
a bearing housing space for housing the bearing;
a lubricating oil flow path communicating between the cooling space and the bearing housing space for sending lubricating oil from the cooling space to the bearing housing space;
a lubricating oil supply port formed on the outer surface of the bearing base, the lubricating oil supply port communicating with the cooling space;
The turbocharger is
Further comprising a lubricating oil supply line configured to send lubricating oil from the outside of the supercharger to the cooling space through the lubricating oil supply port,
supercharger.
The cooling space is formed in an annular shape extending along the circumferential direction of the rotor,
A turbocharger according to claim 1 .
The cooling space is positioned above the axis of the supercharger,
A turbocharger according to claim 1 .