JPH0343455B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to turbochargers.

(Prior Art) In a turbocharger, an annular shroud is attached to a turbine housing that accommodates a turbine wheel, an exhaust passage is formed in the turbine housing for introducing exhaust gas to the turbine wheel, and an exhaust nozzle portion is formed in the exhaust passage. There are some that speed up the exhaust.

In particular, among variable displacement turbochargers proposed in recent years, a variable throttle is formed by a movable vane, and the variable throttle is arranged in series with the nozzle section or independently. In such a variable turbocharger, a variable throttle portion is formed by providing a movable vane on the exhaust passage side of the shroud that is tiltable and slidable on the shroud.

(Problems to be Solved by the Invention) In a turbocharger having such a configuration, when operation is started, the shroud is heated and distorted by the exhaust gas, and this distortion causes a problem in that the clearance of the exhaust passage, particularly the nozzle portion, is disturbed. It was hot. In addition, in the variable displacement turbocharger mentioned above,
This distortion caused a problem in that the shroud interfered with the movable vane and prevented smooth operation of the movable vane.

Furthermore, when the shroud cools and contracts, a gap is created between the inner circumferential end of the shroud and the center housing, causing the problem that exhaust gas leaks from this area.

The present invention was created in view of such problems, and its purpose is to ensure that the movable vane always operates smoothly without disrupting the clearance of the nozzle part.
Further, it is an object of the present invention to provide a turbocharger in which exhaust gas does not leak.

(Means for Solving the Problems) In order to solve the above problems, the present invention combines the compressor housing 11 in which the compressor impeller 21 is housed, and the turbine housing 12 in which the turbine wheel 41 is housed into the center housing 13. an annular shroud 70 that connects the compressed impeller 21 and the turbine wheel 41 by a shaft 20 supported by the center housing 13, and that surrounds the shaft 20 in the turbine housing 12;
The inner peripheral end of the shroud 70 is brought into contact with the center housing 13 to form exhaust passages 39 and 40 that introduce exhaust gas into the turbine wheel 41 into the turbine housing 12, and the shroud 70 is placed on the turbine housing 12 side. It consists of a base plate 36 and a back plate 44 on the center housing 13 side, and the base plate 36
A gap of a predetermined width is formed between the back plate 44 side surface near the inner end and the back plate 44, and the inner circumferential end of the back plate 44 is brought into airtight contact with the center housing 13. A feature is that the inner peripheral end of the base plate 36 is spaced apart from the center housing 13.

(Function) The shroud is composed of a base plate on the turbine housing side and a back plate on the center housing side, and the inner peripheral end of the base plate is separated from the center housing, and a space is provided between the inner peripheral end of the base plate and the back plate. Therefore, the distortion of the base plate can be absorbed between the two, ensuring accurate nozzle clearance, and in the case of a variable displacement turbocharger, preventing the base plate from interfering with the movable vane. can ensure smooth operation.

Further, even when the shroud is cooled and contracted, the inner end of the back plate is always in airtight contact with the center housing, thereby preventing exhaust gas from leaking from the exhaust passage.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

1 to 3 show a turbocharger according to the present invention, and in this embodiment it is a variable displacement turbocharger. Figure 1 is a longitudinal cross-sectional view of the entire structure, Figure 2
The figure is a sectional view taken along the - arrow in FIG. 1, and FIG. 3 is an enlarged sectional view of the main part.

In the figure, reference numeral 11 denotes a compressor housing that rotatably accommodates a compressor impeller, which will be described later.
2 is a turbine housing that rotatably accommodates a turbine wheel, which will be described later; 13 is a center housing that supports a shaft 20 that connects the compressor impeller and the turbine wheel;
and the center housing 13 are integrally joined to each other. A back plate 14 is fixed to the left open end of the compressor housing 11 with bolts 15 and a mounting plate 16, and an axial passage 17 is provided inside.
and a scroll passage 18 are defined. The back plate 14 is attached to the center housing 1 by bolts 19.
It is combined with 3. The left end of the axial passage 17 in the figure communicates with the center of the scroll passage 18, and a shaft 20 is connected to the portion where these passages 17 and 18 communicate.
A compressor impeller 21 attached to the right end in the figure is rotatably housed. The axial passage 17 is an intake inlet 17 that introduces intake air at the right end in the figure.
A is open, and the scroll passage 18 has an intake outlet (not shown) opened upwardly that communicates with a combustion chamber of an engine (not shown).

Two bearing parts 22 and 23 are formed inside the center housing 13, and these bearing parts 22 and 23
The shaft 2 is connected to the bearing holes 22a and 23a formed in the shaft 2 through float bearings 24 and 25, respectively.
0 is rotatably supported. Shaft 20
The right end in the figure rotatably penetrates the back plate 14 via the bush 26 and is connected to the compressor impeller 21, and the left end in the figure is connected to the turbine wheel 41. Note that 27 is a washer, 28 is a collar, and 29 is a thrust bearing, which are interposed between the stepped portion of the shaft 20 and the bush 26.

The center housing 13 also includes float bearings 24 and 2 above the bearings 22 and 23.
The oil supply passage 30 that supplies lubricating oil to the bearing portion 2
Oil drain passage 31 that discharges lubricating oil below 2, 23
A hole 31 (designated with the same reference numeral as the oil drain passage 31) is formed. The refueling passage 30 is
An introduction hole 30a whose upper end is open, and the introduction hole 30a
The right end in the figure is the thrust bearing 2.
A horizontal hole 30b opened on the sliding surface with 9 and the horizontal hole 3
0b, and are connected to the bearing holes 22a, 2, respectively.
Two distribution holes 30c, 30 opened on the circumferential surface of 3a
It is composed of d and. The upper end of the introduction hole 30a is connected to a lubricating oil supply source such as an oil pump (not shown), and the lower end of the hole 31 is connected to an oil pan or the like. These oil supply passage 30 and oil drain passage 31 guide lubricating oil supplied from a lubricating oil supply source to the bearings 24, 25, 29 to provide lubrication and cooling, and then return this lubricating oil to the oil pan. to recover. Note that 32 is a water jacket for cooling water formed on the turbine housing 12 side of the oil supply passage 30 and the oil drainage passage 31, and this water jacket 32 has a water inlet at the bottom and a drain opening at the top. . This water jacket 32 is attached to the turbine housing 1.
It also prevents heat transfer from the bearing part 2, and also evaporates the cooling water during heat soak back and uses the heat of vaporization to cool the bearing part 2.
Cool down 2 and 23.

The turbine housing 12 has stud bolts 3
3 is screwed and fixed to the center housing 13 by a mounting plate 35 fastened to the stud bolt 33 with a nut 34. A shroud 70 surrounding the shaft 20 is attached to the right open end of the turbine housing 12 in the figure, and a top plate 38 is fitted into the inner peripheral portion of the turbine housing 12. Said shroud 70
is composed of a base plate 36 on the turbine housing 12 side and a back plate 44 on the center housing 13 side.

A scroll passage 39 and an outlet passage 40 are defined inside the turbine housing 12, and
An exhaust gas introduction port 39a that opens tangentially to the scroll passage 39 and an exhaust gas discharge port 40a that opens at the left end of the exit passage 40 are formed. The center portion of the scroll passage 39 and the right end portion of the outlet passage 40 communicate with each other, and a turbine wheel 41 fixed to the left end portion of the shaft 20 is rotatably disposed in the portion where these passages 39 and 40 communicate.

The top plate 38 is connected to the turbine housing 1
A cylindrical portion 38a fitted into the inner end of the outlet passage 40 of No. 2 through a seal ring 42;
and a disk portion 38b integrally extending in the radial direction from the axial center portion of the outer periphery. Cylindrical part 3
The aforementioned turbine wheel 41 is rotatably disposed around the outer periphery of the turbine wheel 8a with a predetermined clearance, and the disk portion 38b divides the scroll passage 39 into an outer circumferential path 39b and an inner circumferential path 39c.
Further, a nozzle portion is formed between the cylindrical portion 38a and the base plate 36. This top plate 38
are arranged with slight clearances between the disk portion 38b and the inner wall of the turbine housing 12 and between the cylindrical portion 38a and the inner circumferential wall of the turbine housing 12, respectively.
It is fixed to the base plate 36 by a bolt 37 that passes through the disk portion 38b and the base plate 36 from the side and is screwed into the base plate 36.

The base plate 36 includes a disk portion 36a through which the shaft 20 rotatably passes, and four wing-shaped fixed vanes 4 that integrally extend from the outer periphery of the disk portion 36a toward the top plate 38 in the axial direction.
3, and a flange 36b is integrally formed on the outer periphery of the disc portion 36a. As shown in detail in FIG. 3, the flange 36b is sandwiched between the turbine housing 12 and the center housing 13, and the outer peripheral end of the back plate 44 is welded to the surface of the base plate 36 on the back plate 44 side. ing. This base plate 36 has a clearance 59a between the outer circumferential wall of the disk portion 36a and the inner circumferential wall of the turbine housing 12, respectively. In FIG. 1, 60a is a knock pin for aligning the center housing 13 and the base plate 36 in the rotational direction, and similarly, 60b is a knock pin for aligning the base plate 36 and the top plate 38.

As shown in FIG. 2, the fixed vanes 43 have a partially arcuate shape and are arranged concentrically with the turbine wheel 41 at equal intervals in the rotational direction. Four movable vanes 45 each having a partial arc shape are arranged between these fixed vanes 43, and one side (the right side in FIG. 1) of the movable vane 45 is in sliding contact with the disk portion 36a of the base plate 36. It is free. The fixed vanes 43 and the movable vanes 45 constitute four variable throttles 46 between the outer circumferential path 39b and the inner circumferential path 39c of the scroll passage 39, respectively. Each of the movable vanes 45 has one end fixed to a rotating shaft 47 that rotatably passes through a hole formed in the disk portion 36a of the base plate 36, and tilts as the rotating shaft 47 rotates to open the variable aperture 46.
Change the flow path area (opening degree).

The end of the rotating shaft 47 that protrudes toward the center housing 13 is connected to an actuator via a link mechanism (not shown), and is driven by the actuator.

By the way, the back plate 44 side surface near the inner peripheral end of the base plate 36 and the back plate 44
A gap d of a predetermined width is formed between the center housing 13 and the inner peripheral end of the base plate 36.
It is separated from.

Further, the inner peripheral end of the back plate 44 is in airtight contact with the center housing 13, and in the embodiment, the outer peripheral end of the back plate 44 is connected to the base plate 36.
The back plate 44 is made to have elasticity in the direction A in FIG.
This elasticity allows the inner peripheral end to come into airtight contact with the center housing 13. In this embodiment, the inner peripheral end of the back plate 44 is in contact with the center housing 13 via the heat insulator 48, and the heat insulator 48 is held between the back plate 44 and the center housing 15, and this heat insulator 48 is held between the back plate 44 and the center housing 15. The oscillator 48 reduces heat transfer from the turbine housing 12 side to the center housing 13 side.

Note that 44a is a heat insulating layer formed between the base plate 36 and the back plate 44.

In the above, the surface of the back plate 44 side near the inner peripheral end of the base plate 36 and the back plate 4
A gap d of a predetermined width is formed between the base plate 36 and the center housing 13, and since the inner peripheral end of the base plate 36 is spaced apart from the center housing 13, even if the base plate 36 is distorted due to heating by exhaust air, this distortion is prevented by the gap d. is absorbed, and the nozzle clearance will not be disturbed. In addition, the base plate 36 does not interfere with the movable vane 45, and the movable vane 45
can ensure smooth operation.

Further, even when the shroud 70 cools and contracts, the back plate 44 always contacts the center housing 13 in an airtight manner, thereby preventing exhaust gas from leaking from this portion.

(Effects of the Invention) As described above, according to the present invention, the shroud is configured with a base plate on the turbine housing side and a back plate on the center housing side, and the inner peripheral end of the base plate is separated from the center housing, and the inner peripheral end of the base plate is separated from the center housing. Since a gap is provided between the inner peripheral edge and the back plate,
Distortion of the base plate can be absorbed between the two, ensuring accurate clearance of the nozzle part, and in the case of a variable displacement turbocharger, preventing the base plate from interfering with the movable vane. can ensure smooth operation. Further, even when the shroud is cooled and contracted, the inner end of the back plate is always in airtight contact with the center housing, thereby preventing exhaust gas from leaking from the exhaust passage.

[Brief explanation of drawings]

FIG. 1 is a turbocharger according to the present invention, FIG. 2 is a sectional view taken along the - arrow in FIG. 1, and FIG. 3 is an enlarged sectional view of a main part. In addition, 11 in the drawing is a compressor housing, 1
2 is a turbine housing, 13 is a center housing, 20 is a shaft, 21 is a compressor impeller, 36 is a base plate, 39 and 40 are exhaust passages, 44 is a back plate, 45 is a movable vane,
46 is a variable aperture portion, and 70 is a shroud.

Claims (1)

[Scope of Claims] 1. A compressor housing in which a compressor impeller is housed and a turbine housing in which a turbine wheel is housed are joined via a center housing, and the compressor impeller and the turbine wheel are connected to the center housing. The turbine housing is connected by a shaft supported by a shaft, and the turbine housing is provided with an annular shroud surrounding the shaft, and an inner circumferential end of the shroud is brought into contact with the center housing to direct exhaust gas to the turbine wheel within the turbine housing. forming an exhaust passage for introducing the shroud, an end of the shroud on the center housing side comprising a base plate on the turbine housing side and a back plate on the center housing side, and a surface of the back plate near the inner end of the base plate and the back plate; a gap of a predetermined width is formed in between, a space including the gap is formed between the center housing side end surface of the base plate and the back plate, and the inner peripheral end of the back plate is directly or indirectly connected to the center housing. in airtight contact,
A turbocharger, wherein the space is airtight with the turbine housing, and the inner peripheral end of the base plate is spaced apart from the center housing. 2. The turbocharger according to claim 1, wherein the inner peripheral end of the back plate is brought into elastic contact with the center housing. 3. A heat insulator that is interposed between the turbine wheel and the center housing and reduces heat transfer to the center housing is sandwiched between the inner peripheral end of the back plate and the center housing. A turbocharger according to claim 1. 4. The turbocharger according to claim 1, further comprising a heat insulating layer formed between the back plate and the base plate.