JP5218170B2 - Turbocharger - Google Patents

Description

 The present invention relates to a turbocharger that supercharges air to an engine using kinetic energy of exhaust gas discharged from the engine.

Conventionally, a turbocharger that supercharges air to an engine using kinetic energy of exhaust gas discharged from the engine has been used.
The turbocharger has a turbine and a compressor. Exhaust gas discharged from the engine is introduced into the turbine, and a turbine impeller provided inside the turbine is rotated. The turbine impeller is integrally connected to a compressor impeller provided inside the compressor, and the compressor impeller is rotated by the rotation of the turbine impeller. The rotating compressor impeller compresses the air introduced from the outside, and the compressor supplies the compressed air to the engine, thereby improving the performance of the engine.

The outer shell of the compressor is constituted by a compressor housing. The inner wall of the air flow path formed in the compressor housing is close to the outer peripheral part of the compressor impeller, and the gap between the inner wall of the flow path and the outer peripheral part of the compressor impeller is very small. This is because if the gap is large, the amount of air flowing in the gap increases and the compression efficiency of the air by the compressor decreases.
However, since both the compressor housing and the compressor impeller are formed of a material such as a metal having high hardness, when the gap is excessively reduced, the compressor impeller comes into contact with the inner wall of the flow path by vibration, for example, and the compressor impeller There was a risk of damage.

Therefore, Patent Document 1 discloses a turbocharger in which a substantially annular seal portion facing the outer peripheral portion of the compressor impeller is provided on the inner wall of the flow path in order to prevent the compressor impeller from being damaged.
The seal part disclosed in Patent Document 1 is formed of resin or the like. Therefore, the possibility that the compressor impeller is damaged when the compressor impeller comes into contact with the seal portion due to vibration or the like can be reduced.

Japanese Unexamined Patent Publication No. 2004-299381 (page 8, FIG. 1)

 Incidentally, an inlet for blow-by gas discharged from the engine or the like is provided upstream of the intake port in the compressor. Blow-by gas is gas that leaks from the gap between the piston and cylinder of the engine and the like, and oil and the like are contained therein, causing contamination, and cannot be directly discharged to the outside. Therefore, the blow-by gas is collected at a predetermined location, and after liquid oil or the like is removed by the oil separator, it is introduced into the compressor through the inlet and the inlet. The blow-by gas is compressed by a compressor together with air, supplied again to the engine, and burned with fuel.

Here, the blow-by gas introduced into the compressor contains mist-like oil that could not be removed by the oil separator, and this oil adheres to the surface of the seal part and then solidifies and accumulates. It was observed. The oil has a property of solidifying at a predetermined temperature (for example, 165 ° C.), and since the seal portion is a resin, the heat insulation effect is high, and the temperature is easily maintained higher than that of a metal compressor housing. Therefore, the oil tends to solidify and accumulate on the surface of the seal portion.
The accumulation of oil reduces the width of the air flow path in the compressor housing, causing a problem that the performance and operating characteristics of the turbocharger change.

 The present invention has been made in view of such circumstances, and can prevent oil from solidifying and accumulating on the surface of the seal portion provided in the compressor housing, and can provide stable performance and operating characteristics over a long period of time. The objective is to provide a turbocharger that can be maintained.

In order to solve the above problems, the present invention employs the following means.
A turbocharger according to the present invention is a turbocharger in which a rotor blade is provided inside a compressor housing, and a substantially annular seal portion facing the outer periphery of the rotor blade is provided in the compressor housing. A configuration is adopted in which the outer diameter of the facing surface is equal to or smaller than the outer diameter of the facing portion of the rotor blade facing the seal portion.
In the present invention employing such a configuration, since the outer diameter of the facing surface is equal to or less than the outer diameter of the facing portion of the rotor blade, the facing portion is opposed to the entire facing surface, and the facing surface of the seal portion When oil adheres to the surface, the oil is scraped out by the rotor blades and moves outward in the radial direction of the facing surface.

Further, in the turbocharger of the present invention, the gap between the rotor blade and the seal portion in the vicinity of the peripheral portion on the opposite surface of the seal portion is larger than the gap between the rotor blade and the seal portion in the vicinity of the peripheral portion. The configuration is also wide.
In the present invention employing such a configuration, the air flows radially outward in the gap between the rotor blade and the seal portion in the vicinity of the peripheral portion on the facing surface of the seal portion. The oil adhering to the vicinity of the portion moves to the outside in the radial direction of the opposing surface by being blown away by the flow of air.

In addition, the turbocharger of the present invention employs a configuration in which a surface portion located radially outside the seal portion in the compressor housing is formed flush with the opposing surface of the seal portion.
In the present invention employing such a configuration, air smoothly flows along the opposing surface of the seal portion and the surface portion of the compressor housing, so that the oil adhering to the opposing surface efficiently moves radially outward.

According to the present invention, the following effects can be obtained.
According to the present invention, there is an effect that oil can be prevented from solidifying and accumulating on the surface of the seal portion provided in the compressor housing. Therefore, according to the present invention, since the width of the flow path for allowing air to flow in the compressor housing does not change, there is an effect that the performance and operating characteristics of the turbocharger can be stabilized over a long period of time.

1 is a schematic diagram illustrating an overall configuration of a turbocharger 1 according to a first embodiment. It is an enlarged view of seal part 53 in the 1st embodiment, and its circumference. It is an enlarged view of the 2nd seal part 53A in the 2nd embodiment, and its circumference. It is the schematic which shows the modification of the compressor housing 5 in 1st Embodiment. It is the schematic which shows the modification of the seal part 53 in 1st Embodiment, or the 2nd seal part 53A in 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
The overall configuration of the turbocharger 1 according to the present embodiment will be described with reference to FIG.
FIG. 1 is a schematic diagram showing an overall configuration of a turbocharger 1 according to the first embodiment. An arrow F in FIG. 1 indicates the forward direction.

The turbocharger 1 is a device that supercharges air to the engine using kinetic energy of exhaust gas discharged from an engine (not shown).
As shown in FIG. 1, the turbocharger 1 has a configuration in which a turbine housing 2, a bearing housing 3, a seal plate 4, and a compressor housing 5 are sequentially arranged from the front and integrally provided.

An impeller shaft 6 extending in the front-rear direction is provided inside the bearing housing 3 so as to be rotatable via a plurality of bearings 31.
A turbine impeller 7 and a compressor impeller (rotary blade) 8 which are rotating blades are integrally connected to both ends of the impeller shaft 6, respectively. Each of the turbine impeller 7 and the compressor impeller 8 has a configuration in which a plurality of blades are provided at equal intervals around the rotation axis. The turbine impeller 7 is disposed at a substantially central portion of the turbine housing 2, and the compressor impeller 8 is disposed at a substantially central portion of the compressor housing 5.

The turbine housing 2 has a turbine scroll passage 21 that surrounds the turbine impeller 7 and is formed in a substantially spiral shape along a plane orthogonal to the front-rear direction, and a turbine housing outlet 22 that is an exhaust gas exhaust port. .
The turbine scroll passage 21 communicates with a gas inlet (not shown) into which exhaust gas discharged from the engine is introduced. Further, the turbine scroll flow path 21 communicates with the turbine housing outlet 22 through the installation location of the turbine impeller 7. The turbine housing outlet 22 is connected to an exhaust gas purification device (not shown).

The compressor housing 5 has an intake port 51 that opens rearward and is connected to an air cleaner (not shown), a compressor scroll passage 52 that surrounds the compressor impeller 8 and is formed in a substantially spiral shape along a plane orthogonal to the front-rear direction, A substantially annular seal portion 53 facing the outer peripheral portion of the compressor impeller 8. Further, between the seal plate 4 and the compressor housing 5, a diffuser passage 41 that compresses and pressurizes air is formed in a substantially annular shape centering on the compressor impeller 8.
The intake port 51 communicates with the diffuser flow path 41 via the installation location of the compressor impeller 8, and the diffuser flow path 41 communicates with the compressor scroll flow path 52.
An inlet (not shown) for blow-by gas discharged from the engine or the like is provided between the intake 51 and the air cleaner. Note that the blow-by gas introduced from the introduction port is obtained by removing liquid oil by an oil separator (not shown).

Next, the configuration of the seal portion 53 in the present embodiment will be described with reference to FIG.
FIG. 2 is an enlarged view of the seal portion 53 and the periphery thereof in the first embodiment. An arrow F in FIG. 2 indicates the forward direction.

As shown in FIG. 2, the facing surface 54 of the seal portion 53 facing the compressor impeller 8 has a shape that follows the outer shape of the facing portion 81 of the compressor impeller 8 facing the seal portion 53. A predetermined gap S is formed between the facing surface 54 and the facing portion 81, and the gap S has substantially the same size at any position on the facing surface 54. In addition, the magnitude | size of the clearance gap S in this embodiment is about 0.1 mm.
The outer diameter of the facing surface 54 is formed to be approximately the same as the outer diameter of the facing portion 81. That is, the compressor impeller 8 is configured to face the entire surface of the facing surface 54.

The compressor housing 5 is formed with a recess 55 for providing the seal portion 53. Further, a second recess 56 is formed in the recess 55.
A surface portion 57 located on the radially outer side of the facing surface 54 in the compressor housing 5 is formed flush with the surface of the facing surface 54.

 The seal portion 53 is formed of a resin material having heat resistance (for example, up to 200 ° C.). Further, the resin material is made of a material having such a hardness that prevents the compressor impeller 8 from being damaged when the compressor impeller 8 contacts the seal portion 53 due to vibration or the like.

The seal portion 53 is molded using an injection molding method. The second recess 56 of the compressor housing 5 is filled with the resin material and hardened, so that the seal portion 53 is prevented from coming off from the recess 55 of the compressor housing 5.
However, the molding method of the seal part 53 in the present embodiment is not limited to the molding method described above, and the seal part 53 is mechanically connected to the compressor housing 5 after the seal part 53 is molded from a resin material alone. Also good.

Next, the operation of the turbocharger 1 in this embodiment will be described.
First, the supercharging operation of the turbocharger 1, that is, the operation of supercharging air to the engine using the kinetic energy of exhaust gas discharged from the engine (not shown) will be described.

 Exhaust gas discharged from the exhaust port of the engine is introduced into the turbine scroll passage 21 through the gas inlet of the turbine housing 2. The exhaust gas is introduced into the turbine impeller 7 while flowing in the turbine scroll passage 21 so as to rotate around the turbine impeller 7. By introducing the exhaust gas, the turbine impeller 7 rotates. After rotating the turbine impeller 7, the exhaust gas is discharged from the turbine housing outlet 22, purified by the exhaust gas purification device, and then released to the atmosphere.

Since the turbine impeller 7 is integrally connected to the compressor impeller 8 via the impeller shaft 6, the compressor impeller 8 is also driven by the rotation of the turbine impeller 7.
By the rotation of the compressor impeller 8, the air introduced from the intake port 51 of the compressor housing 5 is sent out to the diffuser flow path 41. The delivered air is pressurized by flowing in the diffuser channel 41. The pressurized air is supplied to the intake port of the engine through the compressor scroll passage 52. By supplying the compressed air to the engine, the performance of the engine can be improved.
Thus, the supercharging operation of the turbocharger 1 is completed.

 Next, the flow of oil contained in the blow-by gas introduced into the turbocharger 1 and the blow-by gas will be described.

 Blowby gas from which liquid oil has been removed by an oil separator is introduced from an inlet (not shown) provided on the upstream side of the intake port 51. The blow-by gas is mixed with air introduced from the outside through an air cleaner, and is introduced into the compressor housing 5 through the intake port 51. Thereafter, the blow-by gas is compressed together with air by the compressor impeller 8 and is supplied to the engine via the diffuser passage 41 and the compressor scroll passage 52. The blow-by gas supplied to the engine is burned together with the fuel.

 The blow-by gas contains mist-like oil (oil mist) that cannot be removed even by an oil separator. When blow-by gas is introduced into the compressor housing 5, the oil adheres to the blade portion of the compressor impeller 8, the inner wall of the diffuser flow path 41, the facing surface 54 of the seal portion 53, and the like. The oil has a property of solidifying at a predetermined temperature (approximately 165 ° C.).

Here, since the compressor impeller 8 rotates at a high speed, even if oil adheres to the blade portion, the compressor impeller 8 is blown radially outward by the rotation. Therefore, oil does not accumulate on the wings of the compressor impeller 8.
In addition, although air is compressed by the compressor impeller 8 and becomes high temperature, the seal plate 4 and the compressor housing 5 that form the diffuser flow path 41 are both made of a metal material, and are short because of their high thermal conductivity. Dissipates heat over time and does not reach a temperature that allows the oil to solidify. Therefore, oil does not accumulate on the inner wall of the diffuser channel 41.

On the other hand, since the seal portion 53 is made of a resin material, its thermal conductivity is low and the temperature is easily maintained high. Therefore, the oil tends to solidify and accumulate on the facing surface 54 of the seal portion 53.
However, even if oil adheres to the surface of the facing surface 54, the facing portion 81 of the compressor impeller 8 is close to the facing surface 54 with a slight gap S, so that the adhered oil is scraped by the compressor impeller 8. And is sent out radially outward. Further, since the compressor impeller 8 is configured to face the entire surface of the facing surface 54, the oil does not solidify and accumulate on the entire surface of the facing surface 54.
Further, since the surface portion 57 of the compressor housing 5 is formed flush with the facing surface 54, the oil scraped out by the compressor impeller 8 smoothly moves from the facing surface 54 to the surface portion 57.

Therefore, oil adhering to the blades of the compressor impeller 8, the inner wall of the diffuser passage 41, the facing surface 54 of the seal portion 53, and the like is sent downstream, introduced into the engine via the compressor scroll passage 52, and burned. .
This completes the flow of the blow-by gas introduced into the turbocharger 1 and the oil contained in the blow-by gas.

Therefore, according to the present embodiment, the following effects can be obtained.
According to this embodiment, there is an effect that oil can be prevented from solidifying and accumulating on the surface of the seal portion 53 provided in the compressor housing 5. Therefore, according to the present embodiment, since the width of the flow path through which air flows in the compressor housing 5 does not change, there is an effect that the performance and operation characteristics of the turbocharger 1 can be stabilized over a long period of time.

[Second Embodiment]
A turbocharger 1 according to this embodiment will be described with reference to FIG.
FIG. 3 is an enlarged view of the second seal portion 53A and the periphery thereof in the second embodiment. An arrow F in FIG. 2 indicates the forward direction. In FIG. 3, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

 The overall configuration of the turbocharger 1 according to the present embodiment and the supercharging operation thereof are the same as those in the first embodiment, and thus description thereof is omitted.

As shown in FIG. 3, the peripheral edge portion 58 of the facing surface 54 in the second seal portion 53 </ b> A is inclined toward the side away from the facing portion 81 of the compressor impeller 8. Therefore, the second gap S2 formed between the peripheral edge portion 58 and the facing portion 81 is wider than the gap S.
Further, the surface portion 57 of the compressor housing 5 is formed flush with the surface of the peripheral edge portion 58.

 Next, the flow of oil attached to the surface of the second seal portion 53A will be described. Note that the flow of the blow-by gas itself is the same as that in the first embodiment, and thus the description thereof is omitted.

The oil adhering to the facing surface 54 of the second seal portion 53A is scraped out by the compressor impeller 8 and moves outward in the radial direction, as in the first embodiment. The oil that has moved toward the outside of the facing surface 54 adheres to the peripheral edge 58.
Here, due to the rotation of the compressor impeller 8, the air flows radially outward in the second gap S <b> 2. Therefore, the oil adhering to the peripheral portion 58 is blown off by the air flow and moves to the outer side in the radial direction of the peripheral portion 58. Therefore, the oil adhering to the peripheral portion 58 can be efficiently sent out to the diffuser channel 41 side.

 Further, since the surface portion 57 of the compressor housing 5 is formed flush with the peripheral edge portion 58, the oil can be smoothly sent out from the peripheral edge portion 58 to the diffuser channel 41 side without inhibiting the air flow. it can.

Therefore, according to the present embodiment, the following effects can be obtained.
According to the present embodiment, in addition to the effect obtained by the first embodiment, there is an effect that oil attached to the peripheral portion 58 of the second seal portion 53A can be efficiently sent out to the diffuser flow path 41 side. .

 Note that the operation procedures shown in the above-described embodiment, or the shapes and combinations of the components are examples, and can be variously changed based on process conditions, design requirements, and the like without departing from the gist of the present invention. is there.

 For example, in the above embodiment, the size of the gap S is 0.1 mm. However, the present invention is not limited to such a configuration, and an appropriate size according to the performance and operating characteristics of the turbocharger. You may choose.

Further, in the first embodiment, the surface portion 57 of the compressor housing 5 is formed flush with the facing surface 54 of the seal portion 53, but the present invention is not limited to such a configuration, and FIG. A configuration as shown in FIG.
FIG. 4 is a schematic view showing a modification of the compressor housing 5 in the first embodiment.
As shown in FIG. 4, the surface portion 57 of the compressor housing 5 is displaced to the side away from the facing portion 81 of the compressor impeller 8. According to such a configuration, the possibility that the peripheral edge portion of the facing portion 81 contacts the surface portion 57 due to vibration or the like can be reduced.

Moreover, in the said embodiment, although the outer diameter of the opposing surface 54 in the seal part 53 and the 2nd seal part 53A is formed substantially the same as the outer diameter of the opposing part 81 in the compressor impeller 8, this invention is such It is not limited to such a configuration, and a configuration as shown in FIG. 5 may be adopted.
FIG. 5 is a schematic view showing a modification of the seal portion 53 in the first embodiment or the second seal portion 53A in the second embodiment.
As shown in FIG. 5, the outer diameter of the facing surface 54 in the seal portion 53 or the second seal portion 53 </ b> A is formed smaller than the outer diameter of the facing portion 81. Even in such a configuration, since the compressor impeller 8 faces the entire surface of the facing surface 54, the oil adhering to the facing surface 54 can be scraped out by the compressor impeller 8 and moved radially outward. .

DESCRIPTION OF SYMBOLS 1 ... Turbocharger, 5 ... Compressor housing, 53 ... Seal part, 53A ... 2nd seal part, 54 ... Opposite surface, 58 ... Peripheral part, 8 ... Compressor impeller (rotary blade), 81 ... Opposite part, S ... Gap, S2 ... Second gap

Claims (2)

A turbocharger in which a rotor blade is provided inside the compressor housing, and an annular seal portion facing the outer periphery of the rotor blade is provided in the compressor housing,
The outer diameter of the facing surface is a surface of the rotary blade and the opposite side of the seal portion, Ri outer diameter or less under der of the opposing portion is a side of the outer facing the sealing portion of the rotor blade,
The gap between the rotary blade and the seal portion in the vicinity of the peripheral portion on the facing surface of the seal portion is wider than the gap between the rotary blade and the seal portion other than in the vicinity of the peripheral portion. Turbocharger characterized by that. Surface portion located radially outward of the seal portion of the compressor housing, the turbocharger according to claim 1, characterized in that it is formed on the facing surface flush of the sealing portion.

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