JP2000282881A - Turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent an impeller from contacting with the inner face of an intake air duct during operation of a turbocharger. SOLUTION: The center of the intake air port 30, formed in a compressor housing 14, is offset in the direction opposite to the position of an exhaust inlet port 18 formed in a turbine housing 12 with respect to the shaft center of the bearing bore 42, in which a shaft 44 is inserted. In this case, the gap between an impeller 40 and the inner face of an impeller chamber 34 is restraines to be small on the side of the exhaust inlet port 18 in relation to the shaft center of the bearing bore 42 and is secured large on the side opposite to the port 18 also. For this reason, even when a shaft 44 moves in the direction opposite to the position of the exhaust inlet port 18 during the operation of a turbocharger 10, the impeller 40 can surely be avoided from contacting with the compressor housing 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger, and more particularly to a structure of a turbocharger that supercharges intake air supplied to an internal combustion engine by using energy of exhaust gas discharged from the internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 59-1575
As disclosed in Japanese Patent No. 39, there is known a turbocharger that supercharges intake air supplied to an internal combustion engine by using the pressure of exhaust gas discharged from the internal combustion engine. The turbocharger includes a turbine wheel provided in an exhaust duct formed in a turbine housing, an impeller provided in an intake duct formed in a compressor housing, and a rotating shaft connecting the turbine wheel and the impeller. ing. In the above conventional device, the turbine wheel rotates by the pressure of exhaust gas from the internal combustion engine. The rotation of the turbine wheel is transmitted to the impeller via the rotation shaft. The impeller supercharges air guided from the atmosphere to the internal combustion engine by rotation of the turbine wheel. Therefore, according to the above-described conventional apparatus, the intake air to the internal combustion engine can be supercharged using the energy of the exhaust gas.

During operation of the internal combustion engine, the turbine housing and the turbine wheel become hot due to the exhaust heat of the exhaust gas, so that the turbine housing and the turbine wheel thermally expand. Therefore, in order to avoid contact between the turbine wheel and the inner surface of the exhaust duct formed in the turbine housing, a large gap is secured between them in consideration of the thermal expansion of the turbine housing and the turbine wheel. It is desirable.

[0004] On the other hand, if an excessive gap is formed between the turbine wheel and the inner surface of the exhaust duct, a large amount of exhaust gas is released into the atmosphere through the gap. In this case, the energy of the exhaust gas cannot be efficiently transmitted to the turbine wheel, and the supercharging efficiency of the turbocharger decreases. Therefore, from the viewpoint of preventing a decrease in supercharging efficiency, it is desirable that the gap between the turbine wheel and the inner surface of the exhaust duct be small.

In the above-mentioned conventional apparatus, the rotation center of the turbine wheel is formed in the turbine housing or the turbine wheel so that the gap becomes large in a portion where the exhaust heat of the exhaust gas is easily transmitted. It is offset with respect to the center of the inlet of the exhaust duct. In other words, the above gap is largely ensured in a portion where the exhaust heat of the exhaust gas is easily transmitted, while being small in other portions. For this reason, according to the above-mentioned conventional device, even if the turbine housing or the turbine wheel expands due to the exhaust heat of the exhaust gas, the contact between the turbine wheel and the inner surface of the exhaust duct is ensured while preventing a decrease in the supercharging efficiency. Can be avoided.

[0006]

During the operation of the internal combustion engine, high-pressure exhaust gas flows through an exhaust duct formed in the turbine housing. In this case, the pressure of the exhaust gas acts as a force for pressing the turbine wheel from the suction port of the exhaust duct in the radial direction of the rotating shaft. The pressure applied to the turbine wheel is transmitted to the rotating shaft. For this reason, in the above configuration, the rotating shaft may move in a direction opposite to the position of the suction port of the exhaust duct.

[0007] A rotating shaft connecting the turbine wheel and the impeller is rotatably inserted into a bearing bore formed in the bearing housing. In order to smoothly rotate the rotating shaft, it is effective to supply lubricating oil to the bearing bore. Lubricating oil is discharged from the oil supply hole formed in the bearing housing to the bearing bore. In such a configuration, the discharge pressure of the lubricating oil discharged from the oil supply hole acts as a force for pressing the rotary shaft from the oil supply hole in the radial direction of the rotary shaft. For this reason, in the above configuration, the rotating shaft may move in a direction opposite to the position of the oil supply hole.

When the rotating shaft moves as described above, the gap between the impeller and the inner surface of the intake duct becomes smaller in the moving direction, and the impeller may come into contact with the inner surface of the intake duct. When the impeller contacts the inner surface of the intake duct, the turbocharger does not operate properly, and it becomes impossible to efficiently supercharge air to the internal combustion engine. Therefore, in order to avoid contact between the impeller and the inner surface of the intake duct in the above case, it is desirable that a large gap is secured between them in the moving direction of the rotating shaft.

However, in the above-mentioned conventional apparatus, the gap between the impeller and the inner surface of the intake duct is not set in consideration of the position of the intake port of the exhaust duct and the position of the lubricating oil supply hole. The present invention has been made in view of the above points, and an object of the present invention is to provide a turbocharger capable of reliably preventing an impeller from contacting an inner surface of an intake duct when a turbocharger operates. .

[0010]

The above object is achieved by the present invention.
As described in the above, a turbocharger comprising an impeller provided in an intake duct, a turbine wheel provided in an exhaust duct, and a bearing bore into which a rotating shaft connecting the impeller and the turbine wheel is inserted. In the turbocharger, the center of the inlet of the intake duct is offset from the axis of the bearing bore in a direction opposite to the position of the inlet of the exhaust duct.

In the present invention, the center of the suction port of the intake duct is offset in the direction opposite to the position of the suction port of the exhaust duct with respect to the axial center of the bearing bore into which the rotating shaft is inserted. That is, the gap between the impeller and the inner surface of the intake duct is small on the intake port side of the exhaust duct with respect to the axis of the bearing bore, and is large on the side opposite to the intake port. Therefore, even when the rotating shaft is pressed in the direction opposite to the position of the intake port of the exhaust duct due to the high-pressure exhaust gas flowing into the intake duct during the operation of the turbocharger, the impeller remains in the intake duct. Can be reliably prevented from contacting the inner surface of the member.

[0012] Further, the above object is achieved by providing an impeller provided in an intake duct, a turbine wheel provided in an exhaust duct, and a rotation connecting the impeller and the turbine wheel. In a turbocharger having a bearing bore into which a shaft is inserted, and an oil supply hole communicating with the bearing bore, the center of the intake port of the intake duct is defined by the oil supply hole with respect to the shaft center of the bearing bore. This is achieved by a turbocharger characterized in that it is offset in the opposite direction to the installation position.

In the present invention, the center of the suction port of the intake duct is offset from the center of the bearing bore in which the rotating shaft is inserted in a direction opposite to the position where the oil supply hole is provided. That is, the gap between the impeller and the inner surface of the intake duct is kept small at the oil supply hole arrangement position side with respect to the shaft center of the bearing bore, and is large at the opposite side to the arrangement position. Therefore, during operation of the turbocharger, the lubricating oil used to smoothly rotate the rotary shaft is discharged from the oil supply hole, so that the rotary shaft is opposite to the oil supply hole arrangement position. Even when the impeller is pressed in the direction, it is possible to reliably prevent the impeller from contacting the inner surface of the intake duct.

[0014]

FIG. 1 is a sectional view of a turbocharger 10 according to a first embodiment of the present invention. FIG. 2 is a view of the turbocharger 10 shown in FIG. 1 as viewed from the direction of arrow III. The turbocharger 10 is a device that supercharges intake air supplied to the internal combustion engine using energy of exhaust gas discharged from the internal combustion engine.

As shown in FIG. 1, a turbocharger 10
Is constituted by a turbine housing 12, a compressor housing 14, and a bearing housing 16. The turbine housing 12 and the bearing housing 16 and the compressor housing 14 and the bearing housing 16 are respectively fixed by bolts (not shown).

The turbine housing 12 is provided with an exhaust inlet port 18 communicating with the internal combustion engine. The exhaust inlet port 18 is formed such that an open surface faces a radial direction of a shaft described later. A scroll chamber 20 communicates with the exhaust inlet port 18. The scroll chamber 20
It is formed so as to surround a turbine wheel which will be described later, and is formed so that its sectional performance becomes smaller as it goes away from the exhaust inlet port 18. The scroll chamber 20 has a function as a flow path for exhaust gas discharged from the internal combustion engine.

A turbine wheel chamber 22 communicates with the inner peripheral side of the scroll chamber 20. Turbine wheel room 2
2, a turbine wheel 24 whose outer peripheral portion is open to the scroll chamber 20 is housed. Turbine wheel 2
Reference numeral 4 has a structure in which a plurality of blades are attached at equal intervals around the axis. When the exhaust gas flows from the scroll chamber 20 into the turbine wheel chamber 22, the turbine wheel 24 is rotated by a plurality of blades being pressed by the exhaust gas.

An exhaust outlet port 26 communicating with the muffler communicates with the turbine wheel chamber 22. The exhaust outlet port 26 is formed so as to face an axial direction of a shaft described later. In such a configuration, exhaust gas discharged from the internal combustion engine flows into the scroll chamber 20 from the exhaust inlet port 18. Then, it flows into the turbine wheel chamber 22 while flowing through the scroll chamber 20,
The exhaust gas is discharged to the muffler through the exhaust outlet port 26.

The compressor housing 14 is provided with an intake port 30 communicating with the atmosphere. The intake port 26 is formed so as to face an axial direction of a shaft described later. As shown in FIG. 2, the intake port 30 is positioned such that the center Ci of the intake port 30 is opposite to the position of the exhaust port 18 (rightward in FIG. 2) with respect to the axis center Cb of a bearing bore described later. The compressor housing 14 is formed so as to be offset by s1.

The inlet port 30 is provided with an impeller chamber 34.
Are in communication. A scroll chamber 36 communicates with the outer peripheral side of the impeller chamber 34. The impeller chamber 34 houses an impeller 40 whose outer peripheral portion is opened to the scroll chamber 36. The scroll chamber 36 is formed so as to surround the impeller 40. The impeller 40 has a structure in which a plurality of blades are attached at equal intervals around the axis.
The impeller 30 has a function of supercharging intake air drawn into the intake port 30 from the atmosphere through the impeller chamber 34 to the scroll chamber 36.

The scroll chamber 36 communicates with an intake outlet port 38 which communicates with the internal combustion engine. The intake outlet port 38 is formed so that an open surface faces a radial direction of a shaft described later. The scroll chamber 36 is formed such that its cross-sectional area increases as it approaches the intake outlet port 38. The scroll chamber 36 has a function as a flow path for sending intake air from the atmosphere to the internal combustion engine via the intake outlet port 38. In such a configuration, the intake air taken into the intake port 30 from the atmosphere is
It flows into the impeller chamber 34 and is sent from the intake outlet port 38 to the internal combustion engine via the scroll chamber 36.

The bearing housing 16 has a cylindrical bearing bore 42 formed therein. A shaft 44 connecting the turbine wheel 24 and the impeller 40 is inserted into the bearing bore 42. Shaft 44
Has an outer diameter smaller than the inner diameter of the bearing bore 42. The shaft 44 is connected to the bearing housing 16.
The thrust bearing 46 is supported in a state where displacement in the axial direction is prohibited.

Around the shaft 44, annular floating bush bearings 48 and 50 are disposed. The floating bush bearings 48 and 50 have an outer diameter slightly smaller than the inner diameter of the bearing bore 42 and have an inner diameter slightly larger than the outer diameter of the shaft 44. Shaft 4
4 is rotatably supported by floating bush bearings 48 and 50. In such a configuration, clearances are secured between the shaft 44 and the inner circumferences of the floating bush bearings 48 and 50 and between the floating bush bearings 48 and 50 and the inner diameter of the bearing bore 42.

The bearing housing 16 has an inlet port 52 through which lubricating oil from the internal combustion engine flows. Oil supply holes 54 and 56 communicating with the bearing bore 42 communicate with the inlet port 52. The lubricating oil flowing from the internal combustion engine into the inlet port 52 is discharged from the oil supply holes 54 and 56 toward the bearing bore 42. When the lubricating oil is discharged to the bearing bore 42, an oil film is formed in the above-described clearance, so that the rotation of the shaft 44 is performed smoothly. The bearing housing 16 has a bearing bore 4
An outlet port 58 communicating with the second port 2 is formed. The lubricating oil flowing from the bearing bore 42 to the outlet port 58 is returned to the internal combustion engine.

Next, the operation of the turbocharger 10 of this embodiment will be described. Turbocharger 1 of this embodiment
At 0, the exhaust gas discharged from the internal combustion engine flows into the scroll chamber 20 from the exhaust inlet port 18. The exhaust gas flowing into the scroll chamber 20 is
In the process of flowing, the blades of the turbine wheel 24 are pressed in the circumferential direction. When the blades of the turbine wheel 24 are pressed in the circumferential direction, the turbine wheel 24 rotates.

When the turbine wheel 24 rotates, the shaft 44 rotates in the bearing bore 42, and the impeller 40 rotates accordingly. When the impeller 40 rotates, the air on the upstream side of the impeller 40 is
Are sent to the scroll chamber 36 under pressure.
Then, the intake air flowing into the scroll chamber 36 is sent to the internal combustion engine via the intake outlet port 38. Therefore,
According to the turbocharger 10 of the present embodiment, the intake air supplied to the internal combustion engine can be supercharged using the energy of the exhaust gas discharged from the internal combustion engine.

During operation of the internal combustion engine, high-pressure exhaust gas flows through the exhaust inlet port 18. in this case,
The exhaust gas pressure acts as a force that presses the turbine wheel 24 from the exhaust inlet port 18 in the radial direction of the shaft 44. The pressure acting on the turbine wheel 24 in the radial direction is transmitted to the shaft 44. For this reason,
In the structure of this embodiment, the pressure of the exhaust gas causes the shaft 44 to move within the bearing bore 42 to the exhaust inlet port 1.
8, that is, the center Ci of the shaft 44 is shifted to the axial center Cb of the bearing bore 42.
In the direction opposite to the position of the exhaust inlet port 18.

When the shaft 44 moves in the radial direction as described above, the impeller 40 connected to the shaft 44 moves in the impeller chamber 34, so that the impeller 40 may come into contact with the compressor housing 14. In order to avoid such a situation, the impeller 40 and the impeller chamber 3
It is desirable that a large gap is secured between the inner surface of the first and fourth inner surfaces.

As a method for ensuring the above-mentioned gap, the impeller is mounted on the compressor housing 14 such that the gap between the impeller 40 and the inner surface of the impeller chamber 34 is increased only in the direction in which the impeller 40 moves when the internal combustion engine is not operating. It is conceivable to form a chamber 36. However, impeller 4
By simply increasing the gap in the movement direction of 0, the gap on the side opposite to the movement direction during the operation of the internal combustion engine increases, and the amount of air flowing into the scroll chamber 36 from the intake port 30 through this gap is reduced. Will increase. Therefore, according to such a method, the air flowing into the intake port 30 cannot be efficiently supercharged toward the internal combustion engine.

During operation of the internal combustion engine, the impeller 40 moves in a direction opposite to the exhaust inlet port 18 as described above. That is, the impeller 40 is connected to the exhaust inlet port 18.
Do not move to the side. Therefore, the gap between the impeller 40 and the inner surface of the impeller chamber 34 can be reduced on the side opposite to the direction in which the impeller 40 moves. When the gap is reduced in this manner, the amount of air flowing through the gap and flowing into the scroll chamber 36 from the intake port 30 is reduced, thereby preventing a decrease in supercharging efficiency. Therefore,
In order to reliably avoid contact between the impeller 40 and the compressor housing 14 without reducing the supercharging efficiency, the gap between the impeller 40 and the inner surface of the impeller chamber 34 must be reduced when the internal combustion engine is not operating. Suitably, it is large in the direction of movement and small in the direction opposite to the direction of movement.

The turbocharger 10 of this embodiment has a compressor housing such that the gap between the impeller 40 and the inner surface of the impeller chamber 34 increases in the moving direction of the impeller 40 and decreases in the direction opposite to the moving direction. The center Ci of the inlet port 30 formed at 14 is
It is characterized in that it is offset with respect to the axial center Cb of the bearing bore 42. Hereinafter, the characteristic portions will be described.

In the turbocharger 10 of the present embodiment, when the internal combustion engine is not operating, the center Ci of the intake port 30 is positioned with respect to the shaft center Cb of the bearing bore 42.
It is offset in a direction opposite to the position of the exhaust inlet port 18. In this case, the gap between the impeller 40 and the inner surface of the impeller chamber 34 is large in the direction in which the impeller 40 moves due to the high pressure state of the exhaust gas, and small in the direction opposite to the moving direction.

When the internal combustion engine is operated, the shaft 44 moves in the bearing bore 42 in the radial direction, so that the center of the shaft 44 substantially coincides with the center Ci of the intake port 30, ie, the impeller. A state is formed in which the gap between 40 and the inner surface of impeller chamber 34 is substantially uniform over the entire circumference. Therefore, according to the present embodiment, even when the shaft 44 moves in the radial direction due to the high pressure of the exhaust gas, it is possible to reliably prevent the impeller 40 from contacting the compressor housing 14. Thereby, the turbocharger 1 of the present embodiment
0 can be operated properly, and as a result, air can be efficiently supercharged to the internal combustion engine.

In this embodiment, the gap between the impeller 40 and the inner surface of the impeller chamber 34 is small on the side opposite to the direction in which the impeller 40 moves. Therefore, according to the present embodiment, the amount of air flowing from the intake inlet port 30 into the scroll chamber 36 through the above gap can be reduced, and as a result, the supercharging efficiency of the turbocharger 10 is reduced. Can be prevented. Therefore, according to the turbocharger 10 of the present embodiment, the impeller 40 can be prevented from coming into contact with the compressor housing 14 without reducing the supercharging efficiency.

If the center Ci of the intake port 30 is offset as described above while the cross-sectional area of the intake port 30 is maintained, the impeller 40 and the impeller chamber 34 are offset.
May be excessively large in the moving direction of the impeller 40 in some cases. When the gap becomes excessive in this manner, the scroll chamber 36 passes through the gap from the intake inlet port 30 and passes through the gap.
There is a possibility that the amount of air flowing into the tank increases and the supercharging efficiency decreases.

FIG. 3 shows the relationship between the inner diameter of the inlet port formed in the compressor housing 14 and the outer diameter of the impeller 42. The relationship between the turbocharger 10 of the present embodiment and the center of the bearing bore 42 is shown in FIG. Shaft center Cb
(Hereinafter, referred to as a first contrast turbocharger) 62 and an intake inlet port 64 having the same cross-sectional area as the intake inlet port 60 of the first contrast turbocharger 62. FIG. 4 shows a diagram in comparison with a turbocharger (hereinafter, referred to as a second turbocharger) 66 in which the center of the inlet port 64 is offset with respect to the axial center Cb of the bearing bore 42. In FIG. 3, the intake port 30 of the turbocharger 10 of the present embodiment is indicated by a solid line, the intake port 60 of the first turbocharger 62 is indicated by a dotted line, and the intake port 64 of the second turbocharger 66 is indicated by a solid line. Each is indicated by a dashed line.

As shown in FIG. 3, the center of the intake port 64 of the second contrast turbocharger 66 is offset with respect to the axial center Cb of the bearing bore 42. In this case, in the second comparative turbocharger 66, the gap between the impeller 40 and the inner surface of the impeller chamber 34 increases in the right direction in FIG. Therefore, in the second comparative turbocharger 66, when the impeller 40 moves in the radial direction, the impeller 40 and the compressor housing 14
The contact with the battery is reliably avoided, while the supercharging efficiency is reduced.

On the other hand, in the turbocharger 10 of this embodiment, the center Ci of the intake port 30 is offset with respect to the axial center Cb of the bearing bore 42, and the sectional area of the intake port 30 is 3 is set smaller than the cross-sectional area of the intake inlet port 64 of the second comparative turbocharger 66 (shaded portion in FIG. 3). For this reason, in the turbocharger 10 of this embodiment, the amount of air flowing into the scroll chamber 36 through the gap from the intake port 30 does not increase, and a decrease in supercharging efficiency is prevented. Therefore, according to the turbocharger 10 of the present embodiment, the supercharging efficiency can be improved while avoiding the contact between the impeller 40 and the compressor housing 14.

In the above embodiment, the intake port 30, the impeller chamber 34, the scroll chamber 36, and the intake port 38 are the "intake duct".
The exhaust inlet port 18, the scroll chamber 20, the turbine wheel chamber 22, and the exhaust outlet port 26 are referred to as an “exhaust duct”, the shaft 44 is referred to as a “rotary shaft”, and the intake inlet port 30 as a claim. The exhaust outlet port 26 corresponds to the “suction port of the exhaust duct” in the claims, and the exhaust outlet port 26 corresponds to the “suction port of the exhaust duct” in the claims.

Next, a turbocharger 70 according to a second embodiment of the present invention will be described with reference to FIG. The turbocharger 70 of this embodiment is different from the turbocharger 10 shown in FIG.
This is realized by changing the offset direction of the bearing bore 42 with respect to the axial center Cb.

FIG. 4 shows a turbocharger 70 of this embodiment.
5 shows a relationship between the positions of the oil supply holes 54 and 56 and the position of the center Ci of the intake inlet port 30 with respect to the shaft center Cb of the bearing bore 42. As shown in FIG. 4, the center Ci of the intake port 30 is opposite to the axial center Cb of the bearing bore 42 in the direction opposite to the position of the oil supply holes 54, 56 communicating with the bearing bore 42 (see FIG. 4). (To the right) by a distance s2.

The shaft 44 connecting the impeller 40 and the turbine wheel 24 is rotatably inserted into a bearing bore 42 formed in the bearing housing 16. In order to smoothly rotate the shaft 44, it is effective to supply lubricating oil to the bearing bore 42. In the present embodiment, the lubricating oil is discharged from the oil supply holes 54 and 56 formed in the bearing housing 16 to the bearing bore 42. In this case, the discharge pressure of the lubricating oil discharged from the oil supply holes 54, 56 acts as a force for pressing the shaft 44 from the oil supply holes 54, 56 in the radial direction of the shaft 44.
For this reason, in the present embodiment, the discharge pressure of the lubricating oil causes the shaft 44 to move in the oil supply hole 5 in the bearing bore 42.
A situation occurs in which it moves in the opposite direction to the positions of 4, 56.

When the shaft 44 moves in the radial direction, the impeller 40 may come into contact with the compressor housing 14 as in the first embodiment. Therefore, in order to reliably avoid the contact between the impeller 40 and the compressor housing 14 without lowering the supercharging efficiency, the gap between the impeller 40 and the inner surface of the impeller chamber 34 should be reduced when the internal combustion engine is not operating. Suitably, it is large in the direction of movement 40 and small in the direction opposite to the direction of movement.

In the turbocharger 70 of this embodiment, as described above, when the internal combustion engine is not operating, the center Ci of the intake inlet port 30 is aligned with the shaft center C of the bearing bore 42.
With respect to b, it is offset in the direction opposite to the position where the oil supply holes 54 and 56 are provided. In this case, impeller 4
The gap between 0 and the inner surface of the impeller chamber 34 increases in the direction in which the impeller 40 moves due to the discharge pressure of the lubricating oil, and decreases in the direction opposite to the moving direction.

When the internal combustion engine is in operation, the gap between the impeller 40 and the inner surface of the impeller chamber 34 becomes substantially uniform over the entire circumference by the shaft 44 moving in the bearing bore 42 in the radial direction. Therefore, according to the present embodiment, even when the shaft 44 moves in the radial direction due to the discharge pressure of the lubricating oil, it is possible to reliably prevent the impeller 40 from contacting the compressor housing 14. Thereby, the turbocharger 10 of the present embodiment can be operated properly, and as a result, air can be efficiently supercharged to the internal combustion engine.

In the first and second embodiments, the center Ci of the intake port 30 is offset with respect to the axial center Cb of the bearing bore 42 formed in the bearing housing 16. Although the intake port 30 is formed in the intake port 14, the method of offsetting the center of the intake port 30 is not limited to this, and the mounting position of the compressor housing 14 and the bearing housing 16 may be offset. It may be.

[0047]

As described above, according to the first and second aspects of the present invention, it is possible to reliably prevent the impeller from contacting the inner surface of the intake duct when the turbocharger operates.

[Brief description of the drawings]

FIG. 1 is a sectional view of a turbocharger according to a first embodiment of the present invention.

FIG. 2 is a view of the turbocharger shown in FIG. 1 as viewed from the direction of arrow III.

FIG. 3 is a diagram in which the relationship between the inner diameter of the intake duct and the outer diameter of the impeller is compared between the turbocharger according to the present embodiment, the first contrast turbocharger, and the second turbocharger.

FIG. 4 is a diagram illustrating a relationship between a position of an oil supply hole and a position of a center of an intake port of an intake duct with respect to an axial center of a bearing bore in a turbocharger according to a second embodiment of the present invention.

[Explanation of symbols]

 10, 70 Turbocharger 12 Turbine housing 14 Compressor housing 24 Turbine wheel 26 Exhaust outlet port 30 Inlet inlet port 40 Impeller 42 Bearing bore 44 Shaft 54, 56 Oil supply hole

Claims (2)

[Claims] An impeller provided in an intake duct;
In a turbocharger comprising: a turbine wheel provided in an exhaust duct; and a bearing bore into which a rotating shaft connecting the impeller and the turbine wheel is inserted, a center of an intake port of the intake duct is defined by the bearing bore. A turbocharger, wherein the turbocharger is offset in a direction opposite to a position of a suction port of the exhaust duct with respect to an axis of the turbocharger. 2. An impeller provided in an intake duct,
A turbocharger comprising: a turbine wheel provided in an exhaust duct; a bearing bore into which a rotating shaft connecting the impeller and the turbine wheel is inserted; and an oil supply hole communicating with the bearing bore. A turbocharger, wherein a center of a suction port of a duct is offset with respect to an axial center of the bearing bore in a direction opposite to an arrangement position of the oil supply hole.