JP2008008173A - Turbosupercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbosupercharger capable of assembling a fixed nozzle into a turbine housing with high accuracy, and suppressing efficiency deterioration. <P>SOLUTION: This turbosupercharger is provided with the turbine housing 10 provided with first and second scroll chambers 20, 21 axially separated from each other in a turbine wheel 110 by a partitioning wall part 30, and the fixed nozzle 50 which has first and second nozzles composed of two or more nozzle vanes 51, 52 and introducing gas in the first and second scroll chambers 20, 21 to the turbine wheel and a disc-like intermediate plate 53 with the first and second nozzles formed, and is arranged in the turbine housing 10. A stepped member 31 engaged with the fixed nozzle 50 and axial positioning is formed on the inner periphery of the partitioning wall part 30 of the turbine housing 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a turbocharger applied to a gasoline engine, a diesel engine or the like.

In a so-called twin scroll turbocharger, for example, as disclosed in Patent Document 1 and the like, the interior of a turbine scroll to which engine exhaust gas is supplied is divided into two in the axial direction of the turbine by a partition wall. A nozzle is provided for each of the two scroll chambers separated from each other. When the engine is running at low speed, the control valve is used to change the area of the introduction part that introduces gas to each scroll chamber, and only one of the scroll chambers is used to increase the supercharging pressure. When the engine is running at high speed, the control valve is opened. The supercharging pressure is suppressed by using both scroll chambers.
Here, an example of a twin scroll turbine housing is shown in FIG.
The turbine housing 300 is divided into two scroll chambers 310 and 320 by a partition wall 330. Such a turbine housing is manufactured by casting, and the scroll chambers 310 and 320 are formed by cores.
The nozzles disposed in the turbine housing 300 are, for example, fixed nozzles having nozzles formed by a plurality of nozzle vanes on both sides of a disk-shaped plate. The fixed nozzle guides the gas flowing through the scroll chambers 310 and 320 to the turbine wheel.
JP 2006-37818 A

By the way, high dimensional accuracy is required for assembling the fixed nozzle and its turbine housing. This is because if the assembling accuracy is low, the flow of the fluid (gas) flowing through the turbine housing 300 is disturbed and the efficiency of the turbine is reduced.
However, since the turbine housing is manufactured by casting, the dimensional accuracy is not so high. In particular, the thickness A of the partition wall 330 that separates the two scroll chambers 310 and 320 requires, for example, a tolerance ΔA of about ± 0.8 mm with a thickness of 3 mm. For this reason, when the fixed nozzle is assembled on the basis of the partition wall 330, there is a problem that sufficient assembling accuracy cannot be obtained and the efficiency of the turbocharger is lowered.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a turbocharger in which a fixed nozzle can be assembled in a turbine housing with high accuracy and efficiency reduction is suppressed. Is to provide a machine.

A turbocharger according to the present invention includes a turbine housing including first and second scroll chambers separated from each other by a partition wall in an axial direction of a turbine wheel, and a plurality of nozzle vanes, and includes a first and a second nozzle vane. The first and second nozzles for guiding the gas in the scroll chamber to the turbine wheel, respectively, and the disk-shaped intermediate plates each having the first and second nozzles formed on both surfaces are disposed in the turbine housing. The partition wall portion of the turbine housing is characterized in that a stepped portion for engaging with the fixed nozzle and positioning in the axial direction is formed on the inner periphery thereof.
According to this configuration, the fixed nozzle can be assembled to the turbine housing with high precision by forming the stepped portion for positioning in the axial direction by engaging the fixed nozzle in the partition wall portion of the turbine housing.

In the above configuration, the fixed nozzle can employ a configuration in which a stepped portion that fits into a stepped portion formed in the partition wall is formed on the outer periphery of the intermediate plate.
According to this, both the positioning of the fixed nozzle in the axial direction and the centering with respect to the axial line can be accurately performed.

In the above configuration, the turbine housing may employ a configuration in which a clearance groove for preventing interference with the tip portion is formed on a surface facing the tip portion of one nozzle of the fixed nozzle. Further, the relief groove can be configured to be processed with reference to a reference surface formed in the step portion of the partition wall portion of the turbine housing.
According to this configuration, if the relief groove is processed with the step portion of the partition wall as a reference, the tip portion of one nozzle of the fixed nozzle is appropriately abutted against the opposing surface, so that high assembly accuracy can be obtained.

In the above configuration, the fixed nozzle may be configured to be sandwiched between the turbine housing and a shroud plate having a heat shielding function fixed to the turbine housing. Moreover, in the said structure, the structure contacted with the shroud plate of a turbine housing can be employ | adopted as the process processed on the basis of the reference plane formed in the level | step-difference part of the partition part of a turbine housing.
According to this configuration, the structure can be simplified by fixing the fixed nozzle using the shroud plate having a heat shielding function, and the contact surface that contacts the shroud plate of the turbine housing is formed in the step portion of the partition wall portion. High assembling accuracy can be obtained by processing with the reference plane as a reference.

  ADVANTAGE OF THE INVENTION According to this invention, the fixed nozzle can be assembled | attached in a turbine housing with high precision, and the turbocharger by which the efficiency fall was suppressed is provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
FIG. 1 to FIG. 6 are diagrams showing an embodiment of a turbocharger according to the present invention, and FIG. 1 is a diagram showing a configuration of a main part of the turbocharger according to an embodiment of the present invention. 2 is a sectional view of the turbine housing, FIG. 3 is a perspective view of the fixed nozzle, FIG. 4 is a side view of the fixed nozzle, FIG. 5 is a perspective view of the shroud plate, and FIG. 6 is a sectional view along the axial direction of the shroud plate. .

  This turbocharger is applied, for example, to supercharging of an engine. As shown in FIG. 1, as shown in FIG. 1, a turbine wheel 110 in which a turbine housing 10 and a turbine blade 100 are formed, one end of which is a turbine wheel 110. The rotating shaft 120 is connected to a compressor (not shown) at the other end, a fixed nozzle 50 disposed in the turbine housing 10, a shroud plate 70 having a heat shielding function fixed to the turbine housing 10 with a bolt (not shown), and the like. It is configured.

As shown in FIGS. 1 and 2, the turbine housing 10 includes first and second scroll chambers 20 and 21 that are separated from each other by an annular partition wall 30 in the axial direction of the turbine wheel 100. The exhaust gas introduced from 16 is guided to the first and second scroll chambers 20 and 21. As shown in FIG. 1, the gas passage 16 is provided with a control valve 35, and the passage area can be adjusted by the control valve 35.
The turbine housing 10 is cast from a metal material such as cast iron, and internal spaces such as the first and second scroll chambers 20 and 21 separated by the partition wall 30 are formed by a core.

  Further, as shown in FIG. 2, the turbine housing 10 forms a stepped portion 31 for positioning in the axial direction of a fixed nozzle 50 (described later) formed on the inner periphery of the partition wall portion 30 and a side wall of the first scroll chamber 20. In addition, an annular relief groove 40 formed on a facing surface where a tip 51a of a nozzle vane 51 of a fixed nozzle 50, which will be described later, faces (abuts), and a shroud plate 70, which will be described later, come into contact with the shroud plate 70 in the axial direction. An annular contact surface 45 and the like for positioning in FIG.

The stepped portion 31 has a reference surface 31a machined so that the axial distance (depth) from the one end surface of the partition wall portion 30 is a predetermined value, and the reference surface 31a is used for a fixed nozzle 50 described later. The fixed nozzle 50 is positioned in the axial direction by contacting with the annular contact surface 55a. A cylindrical inner peripheral surface 31b of the step portion 31 is also machined, and a cylindrical outer peripheral surface 55b of a fixed nozzle 50 described later is fitted to the inner peripheral surface 31b. As a result, the axis of the fixed nozzle 50 with respect to the turbine housing 10 is centered.

The escape groove 40 is machined so that the distance in the axial direction from the reference surface 31a of the stepped portion 31 becomes a predetermined value. Specifically, the relief groove 40 is machined so as to have a depth at which a tip end portion 51a of a nozzle vane 51 of a fixed nozzle 50, which will be described later, positioned at the step portion 31 abuts (contacts).
The contact surface 45 is machined so as to be substantially flush with a rear end surface 56a of the base 56 of the fixed nozzle 50 described later, that is, the axial distance from the reference surface 31a becomes a predetermined value. Accordingly, when an annular contact surface of a shroud plate 70 described later contacts the contact surface 45, the shroud plate 70 is positioned in the axial direction and abuts against a rear end surface 56a of the base 56 of the fixed nozzle 50 described later.

As shown in FIGS. 3 and 4, the fixed nozzle 50 is formed integrally with a plurality of nozzle vanes 51 and nozzle vanes 51 constituting nozzles disposed on the inner peripheral side of the first scroll chamber 20. The annular intermediate plate 53, a plurality of nozzle vanes 52 constituting a nozzle disposed on the inner peripheral side of the second scroll chamber 21 formed on the other end surface of the intermediate plate 53, and a base portion of the nozzle vane 52 are integrally formed. This fixed nozzle is precisely machined by machining.
A stepped portion 55 is machined on the outer peripheral portion of the intermediate plate 53, and the stepped portion 55 includes an annular contact surface 55 a that contacts the reference surface 31 a of the stepped portion 31 formed in the partition wall portion 30, and a stepped portion. A cylindrical outer peripheral surface 55b fitted to the inner peripheral surface 31b of the portion 31 is provided.

As shown in FIGS. 5 and 6, the shroud plate 70 has an annular outer shape, and includes a through hole 72 through which the rotary shaft 120 shown in FIG. 1 passes, and is not shown in the turbine housing 10. And the fixed nozzle 50 is held (clamped) in cooperation with the housing 10, and has a heat shielding function for blocking the release of heat from the turbine housing 10 toward the compressor (not shown).
The shroud plate 70 includes an annular contact surface 71 that is perpendicular to an axis that contacts the contact surface 45 formed on the turbine housing 10, and the contact surface 71 is machined. It is positioned in the axial direction by coming into contact with the contact surface 45, and is substantially in contact with the rear end surface 56 a of the base 56 of the fixed nozzle 50.

  7 to 9 are sectional views showing a state in which the fixed nozzle 50 and the shroud plate 70 are assembled to the turbine housing 10. FIG. 7 shows the dimensions of the partition wall 30 of the turbine housing 10 as the design value A. 8, FIG. 8 shows a case where the dimension of the partition wall 30 is thin by a tolerance ΔA, and FIG. 9 shows a case where the dimension of the partition wall 30 is thick by a tolerance ΔA.

As shown in FIG. 7, when the dimension of the partition wall 30 of the cast turbine housing 10 is equal to the design value A, the housing 10 has a clearance groove 40 at a predetermined distance L1 from the reference surface 31a (the contact of the fixed nozzle 50). The tip of the nozzle vane 51 of the fixed nozzle 50 is substantially in contact with the escape groove 40. The distance between the surface 55a and the tip of the nozzle vane 51 is processed.
Further, the contact surface 45 of the turbine housing 10 is positioned at a predetermined distance L2 from the reference surface 31a (the distance from the contact surface 55a of the fixed nozzle 50 to the rear end surface 56a of the base 56), that is, from the reference surface 31a to the fixed nozzle. The 50 bases 56 are processed at a distance to the rear end surface 56a. Thereby, the contact surface 71 of the shroud plate 70 is positioned at an appropriate position, and the contact surface 71 and the rear end surface 56a of the base 56 of the fixed nozzle 50 are substantially in contact. Thereby, the fixed nozzle 50 is assembled in the turbine housing 10 with high accuracy.

Further, as shown in FIG. 8, when the dimension of the partition wall portion 30 of the cast turbine housing 10 is thin by the tolerance ΔA, the depth of the escape groove 40 becomes deeper than that shown in FIG. If the size of the partition wall 30 is further reduced, the distance from the reference surface 31a to the contact surface 45 becomes longer than the predetermined distance L2, and in this case, the cast turbine housing 10 is a defective product. Further, as shown in FIG. 9, when the dimension of the partition wall portion 30 of the cast turbine housing 10 is thick by the tolerance ΔA, the escape groove 40 is not formed. In this case, since the dimension of the partition wall portion 30 is too thick, the turbine housing 10 is a defective product.
That is, even if the dimensions of the partition wall portion 30 vary, an appropriate clearance groove 40 having a depth corresponding to the dimension of the partition wall portion 30 can be machined if it is between the design value A + tolerance ΔA to the design value A−tolerance ΔA. Thus, the fixed nozzle 50 can be assembled to the turbine housing 10 with high accuracy.

  As described above, according to the present embodiment, if the dimensional accuracy of the partition wall portion 30 of the turbine housing 10 manufactured by casting is within a predetermined tolerance, the partition wall portion 30 is fixed even if there is a variation in dimensions. The nozzle 50 can be assembled to the turbine housing 10 with high accuracy.

It is a figure which shows the structure of the principal part of the turbocharger which concerns on one Embodiment of this invention, Comprising: It is an external appearance perspective view partially including a fracture | rupture cross section. It is sectional drawing of a turbine housing. It is a perspective view of a fixed nozzle. It is a side view of a fixed nozzle. It is a perspective view of a shroud plate. It is sectional drawing along the axial direction of a shroud plate. It is sectional drawing which shows an example of the positional relationship of a turbine housing, a fixed nozzle, and a shroud plate. It is sectional drawing which shows the other example of the positional relationship of a turbine housing, a fixed nozzle, and a shroud plate. It is sectional drawing which shows the further another example of the positional relationship of a turbine housing, a fixed nozzle, and a shroud plate. It is sectional drawing for demonstrating the problem of the dimensional error of the partition part which generate | occur | produces when casting a turbine housing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Turbine housing 15, 16 ... Gas passage 20 ... 1st scroll chamber 21 ... 2nd scroll chamber 30 ... Partition part 31 ... Step part 31a ... Reference surface 31b ... Inner peripheral surface 35 ... Control valve 40 ... Escape groove 45 ... Abutting surface 50 ... Fixed nozzle 51 ... Nozzle vane 51a ... Front end 52 ... Nozzle vane 53 ... Intermediate plate 55 ... Step part 55a ... Abutting surface 55b ... Outer peripheral surface 56 ... Base 56a ... Rear end surface 70 ... Shroud plate 71 ... Abutting Surface 72 ... Through hole 100 ... Turbine blade 110 ... Turbine wheel 120 ... Rotating shaft A ... Design value [Delta] A ... Tolerance

Claims (6)

A turbine housing comprising first and second scroll chambers separated from each other by a partition wall in the axial direction of the turbine wheel;
First and second nozzles configured by a plurality of nozzle vanes for guiding the gas in the first and second scroll chambers to the turbine wheel, respectively, and disks each having the first and second nozzles formed on both sides An intermediate plate having a shape, and a fixed nozzle disposed in the turbine housing,
The turbocharger is characterized in that the partition wall portion of the turbine housing is formed with a step portion for positioning in the axial direction by engaging with the fixed nozzle on the inner periphery thereof.   2. The turbocharger according to claim 1, wherein the fixed nozzle has a stepped portion that fits into a stepped portion formed in the partition wall portion on an outer periphery of the intermediate plate.   3. The turbine housing according to claim 1 or 2, wherein a clearance groove for preventing interference with the tip portion is formed on an opposing surface facing the tip portion of one nozzle of the fixed nozzle. The turbocharger described.   4. The turbocharger according to claim 3, wherein the escape groove is processed with reference to a reference surface formed in a step portion of a partition wall portion of the turbine housing.   The turbocharger according to any one of claims 1 to 4, wherein the fixed nozzle is sandwiched between the turbine housing and a shroud plate fixed to the turbine housing. 6. The turbocharger according to claim 5, wherein a contact surface of the turbine housing that contacts the shroud plate is processed with reference to a reference surface formed at a step portion of a partition wall portion of the turbine housing. Feeder.

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