JP2015165108A - turbine housing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbine housing capable of suppressing corrosion due to condensate water.SOLUTION: A turbine housing 31 comprises: a housing body 40 that includes a turbine chamber 32 in which a turbine wheel is accommodated; and a cylindrical inner wall member 50 provided separately from the housing body 40 and constituting an inner circumferential wall of the turbine chamber 32 including at least an inner wall of a shroud. A discharge groove 41 is formed in a downward region, in a gravity direction, in a part covered with the inner wall member 50 on an inner circumferential surface of the housing body 40 to extend in parallel to a rotational axis L1 of a turbine wheel up to an upstream end portion, in an exhaust gas flow direction, of the part covered with the inner wall member 50. A bottom of the discharge groove 41 is inclined with respect to a horizontal direction so as to be located downward in the gravity direction as being closer to the end portion.

Description

  The present invention relates to a turbine housing.

  In recent years, it has been proposed to provide an inner wall member constituting an inner peripheral wall of a turbine chamber in which a turbine wheel is accommodated in the turbine housing. In the turbine housing of Patent Document 1, an insulator that functions as a heat insulating material is provided on the inner peripheral surface of the turbine chamber in the housing body.

Special table 2013-509534 gazette

  In the turbine housing, since the housing body and the inner wall member are separate, a gap is formed at the contact portion between the housing body and the inner wall member. And if the condensed water which generate | occur | produced in the turbine housing penetrate | invades in this clearance gap, there exists a possibility that a housing main body and an inner wall member may corrode by the electric corrosion etc. by the condensed water.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a turbine housing capable of suppressing corrosion due to condensed water.

  A turbine housing for achieving the above object includes a housing main body having a turbine chamber in which a turbine wheel is accommodated, and an inner peripheral wall of at least a shroud portion provided inside the housing main body separately from the housing main body. A cylindrical inner wall member constituting the inner peripheral wall of the turbine chamber. The turbine wheel is a portion covered with the inner wall member on the inner peripheral surface of the housing main body, and is located at a lower portion in the gravitational direction to an end portion on the upstream side in the exhaust flow direction of the covered portion. A groove extending in parallel with the rotation axis is formed. The groove is inclined with respect to the horizontal direction so that the bottom of the groove approaches the end in the gravity direction.

  In the turbine housing, when condensed water generated at a low temperature enters the gap between the housing main body and the inner wall member, the condensed water flows down into a groove formed on the inner peripheral surface of the housing main body due to gravity, and the groove Flows to the upstream end in the exhaust flow direction, and is discharged to the outside of the gap. Thus, according to the turbine housing, since the condensed water can be discharged from the gap between the housing main body and the inner wall member, corrosion of the housing main body and the inner wall member due to the condensed water can be suppressed.

1 is a cross-sectional view schematically showing a cross-sectional structure of a turbocharger to which a turbine housing of an embodiment is applied. Sectional drawing which shows the cross-section of the turbine housing. Sectional drawing which shows an expanded sectional structure of an inner wall member and its periphery. Sectional drawing which shows the cross-sectional structure of the discharge groove periphery at the time of low temperature. Sectional drawing which shows the cross-sectional structure of the discharge groove periphery at the time of high temperature.

Hereinafter, an embodiment of the turbine housing will be described.
As shown in FIG. 1, the turbocharger 10 includes a compressor 20 disposed in the intake passage 2 of the internal combustion engine 1, a turbine 30 disposed in the exhaust passage 3 of the internal combustion engine 1, the compressor 20 and the turbine. And a center housing 11 for connecting 30.

  The compressor 20 includes a compressor housing 21. A compressor chamber 22 is formed inside the compressor housing 21, and a compressor wheel 23 is accommodated in the compressor chamber 22. On the other hand, the turbine 30 includes a turbine housing 31. A turbine chamber 32 is formed inside the turbine housing 31, and a turbine wheel 33 is accommodated in the turbine chamber 32. A shaft 12 is rotatably supported on the center housing 11. A compressor wheel 23 is fixed to one end of the shaft 12, and a turbine wheel 33 is fixed to the other end. The turbocharger 10 has a structure in which the compressor wheel 23 and the turbine wheel 33 rotate integrally.

  The compressor chamber 22 extends along the rotation axis L <b> 1 of the compressor wheel 23. The compressor housing 21 is formed with a scroll passage 24 extending in a spiral shape on the outer periphery of the compressor wheel 23.

  On the other hand, the turbine chamber 32 extends along the rotation axis L <b> 1 of the turbine wheel 33. The turbine housing 31 is formed with a scroll passage 34 extending in a spiral shape on the outer periphery of the turbine wheel 33. The scroll passage 34 is opened in an annular shape over the entire circumference of the peripheral wall of the turbine chamber 32.

  The turbocharger 10 supercharges the internal combustion engine 1 as follows. When the exhaust gas of the internal combustion engine 1 is blown onto the turbine wheel 33 through the scroll passage 34, the turbine wheel 33 rotates by receiving the energy of the exhaust flow. Then, the rotation of the turbine wheel 33 is transmitted to the compressor wheel 23 through the shaft 12, and the compressor wheel 23 rotates. Thereby, in the compressor 20, the intake air flowing into the compressor chamber 22 from the inlet 20 a of the compressor 20 is sent to the scroll passage 24 and eventually to each cylinder of the internal combustion engine 1 by the action of the centrifugal force due to the rotation of the compressor wheel 23. It is done. In the internal combustion engine 1, the output can be improved by performing supercharging using the energy of the exhaust.

  The turbocharger 10 is a water-cooled type. Specifically, a cooling water channel 35 for circulating the cooling water is formed inside the housing body 40. The turbine housing 31 is cooled by forcibly circulating the cooling water inside the cooling water passage 35. In the present embodiment, a part of the cooling water used for cooling the internal combustion engine 1 during operation of the internal combustion engine 1 is supplied to the cooling water passage 35 and circulated.

  As shown in FIG. 1 or FIG. 2, the turbine housing 31 includes a housing body 40 and an inner wall member 50 attached to the inside of the housing body 40. The housing body 40 is made of an aluminum alloy. The inner wall member 50 is made of a material having high heat resistance and higher thermal conductivity than the housing body 40 (in this embodiment, stainless steel). Thus, in this embodiment, the inner wall member 50 formed separately from the housing body 40 is provided inside the housing body 40. Further, the inner wall member 50 is formed in a cylindrical shape in which one end (left side in FIG. 1) has an enlarged diameter.

  The inner wall member 50 includes a part of the turbine chamber 32 on the downstream side in the exhaust flow direction from the turbine wheel 33, a part that becomes the peripheral wall of the turbine wheel 33 (the inner peripheral wall of the so-called shroud part), and the scroll passage 34. It is attached to the inside of the housing body 40 so as to form the inner wall of the portion on the turbine wheel 33 side. The inner wall member 50 is disposed in a state in which a portion on the side of the expanded shape forms the shroud portion and the inner wall of the scroll passage 34.

  In the turbine housing 31, since the housing body 40 and the inner wall member 50 are formed separately, a gap is formed at the contact portion between the housing body 40 and the inner wall member 50. Since this gap is very small, when the condensed water generated in the turbine housing 31 enters, the condensed water tends to accumulate. Therefore, there is a possibility that corrosion of the housing body 40 and the inner wall member 50 may be caused by electrolytic corrosion due to condensed water entering the gap.

  Therefore, in the present embodiment, a discharge groove 41 for discharging condensed water to the outside is provided between the housing main body 40 and the inner wall member 50. Hereinafter, the discharge groove 41 will be described in detail.

  As shown in FIGS. 3 and 4, the discharge groove 41 is a portion covered with the inner wall member 50 on the inner peripheral surface of the housing body 40, and the turbine wheel 33 is formed at the lowermost portion in the gravity direction. Are formed in a shape extending in parallel with the rotation axis L1. The discharge groove 41 extends to an end portion on the upstream side (left side in FIG. 3) in the exhaust flow direction of the portion of the inner peripheral surface of the housing body 40 covered with the inner wall member 50. Further, the discharge groove 41 is inclined with respect to the horizontal direction so that the bottom thereof becomes closer to the lower side in the gravity direction as it approaches the end.

Hereinafter, the effect | action by providing such the discharge groove 41 is demonstrated.
In the turbine housing 31, when condensed water generated at a low temperature such as when the operation of the internal combustion engine 1 is stopped enters the gap between the housing main body 40 and the inner wall member 50, this is indicated by a white arrow in FIG. 4. The condensed water flows along the gap due to gravity and flows down into the discharge groove 41. Then, as shown by the white arrow in FIG. 3, this condensed water flows through the inside of the discharge groove 41 to the upstream end in the exhaust flow direction, and from the same end, the housing body 40 and the inner wall member 50 Is discharged outside the gap (specifically, in the scroll passage 34). As described above, according to the turbine housing 31, the condensed water can be discharged from the gap between the housing main body 40 and the inner wall member 50, so that the corrosion of the housing main body 40 and the inner wall member 50 due to the condensed water can be suppressed.

  FIG. 5 shows a cross-sectional structure around the discharge groove 41 at a high temperature. As shown in FIG. 5, in the turbine housing 31, the depth of the discharge groove 41 is determined by the inner wall member 50 that thermally expands when the turbine housing 31 becomes hot as the internal combustion engine 1 is operated. Is set to fill.

  The inner wall member 50 has a large amount of thermal expansion because it directly touches the exhaust gas and becomes high temperature, whereas the housing main body 40 is cooled by the cooling water and becomes relatively low in temperature, so the amount of thermal expansion is small. In the turbine housing 31, due to such a difference in thermal expansion amount, the outer peripheral surface of the inner wall member 50 is pressed against the inner peripheral surface of the housing body 40 at a high temperature. At this time, the inner wall member 50 fills the discharge groove 41 of the housing body 40. Thereby, when the turbocharger 10 is operated, the discharge groove 41 connected to the gap between the housing main body 40 and the inner wall member 50 can be closed, so that the operation efficiency of the turbocharger 10 resulting from the formation of the discharge groove 41 is improved. The decrease can be suppressed.

  Further, since the inner wall member 50 is allowed to slightly expand, the temperature of the turbine housing 31 is lower than that in which the outer peripheral surface of the inner wall member 50 and the inner peripheral surface of the housing body 40 are firmly fixed at low temperatures. Generation of internal stress in the inner wall member 50 and the housing main body 40 due to the change is suppressed, and thereby the reliability of the turbine housing 31 can be improved.

  Further, in the turbine housing 31, the inner wall member 50 is not firmly fixed to the housing main body 40, and is in a state where a slight relative movement is possible. Inside the turbine housing 31, the pressure P <b> 1 (FIG. 3) of a portion downstream of the inner wall member 50 in the exhaust flow direction (for example, a portion downstream of the turbine wheel 33 in the turbine chamber 32) is in the exhaust flow direction of the inner wall member 50. Lower than the pressure P2 of the upstream portion (for example, the scroll passage 34) (P1 <P2). Therefore, when the internal combustion engine 1 is operated and such a pressure difference is generated, the inner wall member 50 is pressed toward the downstream side in the exhaust flow direction due to the pressure difference. As a result, the end of the inner wall member 50 on the upstream side in the exhaust flow direction, that is, the portion with the expanded diameter is pressed against the inner surface of the housing main body 40, so that the inner wall member 50 and the housing main body 40 at the same end are in close contact with each other. The degree becomes higher, and this also closes the discharge groove 41.

As described above, according to the present embodiment, the following effects can be obtained.
(1) A discharge groove having a shape extending in parallel with the rotation axis L1 of the turbine wheel 33 at a lowermost portion in the gravitational direction on the inner peripheral surface of the housing main body 40 covered with the inner wall member 50. 41 was formed. The discharge groove 41 is extended to the end of the inner peripheral surface of the housing body 40 covered by the inner wall member 50 on the upstream side in the exhaust flow direction, and the bottom of the discharge groove 41 is moved closer to the end. It was inclined with respect to the horizontal direction so as to be on the lower side in the direction of gravity. Thereby, since condensed water can be discharged | emitted from the clearance gap between the housing main body 40 and the inner wall member 50 through the discharge groove 41, corrosion of the housing main body 40 and the inner wall member 50 by condensed water can be suppressed.

The above embodiment may be modified as follows.
The housing body 40 and the inner wall member 50 may be firmly fixed so as not to move relative to each other.

  -Not only forming one discharge groove 41 but you may form two or more. In this case, these discharge grooves may be formed in portions of the inner peripheral surface of the housing main body 40 that are covered with the inner wall member 50 and on the lower side in the gravity direction.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Intake passage, 3 ... Exhaust passage, 10 ... Turbocharger, 11 ... Center housing, 12 ... Shaft, 20 ... Compressor, 20a ... Inlet part, 21 ... Compressor housing, 22 ... Compressor chamber, 23 ... Compressor wheel, 24 ... scroll passage, 30 ... turbine, 31 ... turbine housing, 32 ... turbine chamber, 33 ... turbine wheel, 34 ... scroll passage, 35 ... cooling water passage, 40 ... housing body, 41 ... discharge groove, 50 ... inner wall Element.

Claims (1)

A housing main body having a turbine chamber in which a turbine wheel is accommodated, and a cylindrical shape which is provided separately from the housing main body inside the housing main body and includes at least an inner peripheral wall of a shroud portion. A turbine housing comprising:
Rotation of the turbine wheel to a portion of the inner peripheral surface of the housing body covered with the inner wall member, at a lower portion in the gravitational direction, to an end portion on the upstream side in the exhaust flow direction of the covered portion. A groove extending in parallel with the axis is formed,
A turbine housing that is inclined with respect to a horizontal direction so that a bottom portion of the groove approaches a lower side in a gravitational direction as the end portion is approached.