JPS63143327A - Housing structure of turbocharger - Google Patents

Abstract

PURPOSE:To always maintain a proper clearance by providing said clearance in between a shroud and a turbine housing while positioning said shroud with a center housing as a reference. CONSTITUTION:A compressor housing 11 which houses a compressor impeller 21 is joined to a turbine housing 12 which houses a turbine wheel 41 via a center housing 13. Also, the turbine wheel 41 is surrounded by a shroud (vane holding member) 36, and the wheel 41 and the impeller 21 are connected by means of a shaft 20. In this structure, an aligning hole 13a and a boss 36c which are provided on the center housing 13 and the shroud 36 respectively as aligning means are fitted to each other to determined their positions. And, a defined clearance is provided in between the shroud 36 and the turbine housing 12.

Description

Detailed Description of the Invention (Field of Application in Industry A) This invention relates to a housing structure of a turbocharger, and more specifically, a shroud surrounding a turbine wheel is provided spaced apart from the turbine housing and positioned by a center housing. The present invention relates to a housing structure that prevents the clearance between a shroud and a turbine wheel from changing due to thermal strain.

(Prior Art) As described in Japanese Patent Publication No. 61-37791, a turbocharger connects a compressor housing and a turbine housing through a center housing, and connects a compressor impeller housed in the compressor housing to the turbine housing. The turbine wheel housed in the center housing is connected to the turbine wheel by a shaft supported by the center housing. Since such turbochargers generally operate at high temperatures due to the influence of exhaust heat, each housing is made of heat-resistant steel such as stainless steel, and the center housing that supports the shaft is cooled to prevent shaft seizure. To prevent. However, in such a turbocharger, since the turbine housing and the center housing are in direct contact over a large area, the amount of heat transferred to the center housing is large, and the assembly of the center housing and the turbine housing requires a relatively large amount of work. The disadvantage is that it is difficult to accurately control the clearance between the turbine housing and the turbine wheel due to the tolerances allowed.

Therefore, the applicant has filed the patent application No. 61-12499.
In Specification No. 6 (submitted May 30, 1986), etc., a base plate is fitted to the turbine housing between the turbine housing and the center housing, and a top plate is fixed to the base plate within the turbine housing. proposed a turbocharger that surrounds a turbine wheel and directs exhaust gas to the turbine wheel to drive the turbine wheel. In the turbocharger according to this prior application, the base plate prevents heat transfer to the center housing, and the top plate is arranged concentrically around the outer circumference of the turbine wheel to reduce the clearance (nozzle part) between the outer circumference of the top plate and the turbine wheel. to accurately manage the clearance around the outer circumference of the turbine wheel.

(Problem to be solved by this invention) However,
In the turbocharger according to this prior application, the base plate fits into the turbine housing and the outer circumferential surface of the base plate is in close contact with the inner circumferential surface of the turbine housing, so that the turbine housing suffers thermal distortion due to exhaust heat. This thermal distortion also causes distortion in the base plate, which has the disadvantage of causing the concentricity of the turbine wheel and the tongue plate to become out of order. In other words, the turbine housing generally has an asymmetrical shape with a spiral scroll passage that generates a swirling flow in the exhaust gas and an exhaust gas inlet that opens tangentially to the scroll passage. Distortion was also large locally, and the concentricity was also greatly distorted due to the distortion of the base plate. As a result, the interference between the turbine wheel and the top plate forming the nozzle portion and the amount of exhaust gas leaking from around the turbine wheel also increase, causing a reduction in turbine efficiency.

The present invention was made in view of the above drawbacks, and provides a housing structure for a turbocharger that prevents concentricity between the top plate and the turbine wheel from being lost due to thermal distortion of the turbine housing, and prevents interference between the turbine wheel and the turbine wheel. The purpose is to prevent a decline in efficiency.

(Means for Solving Problems) A housing structure of a turbocharger according to the present invention connects a compressor housing in which a compressor impeller is housed and a turbine housing in which a turbine wheel is housed through a center housing. A turbocharger in which at least one shroud is disposed within a housing, the shroud surrounds a turbine wheel, and the turbine wheel and the compressor impeller are connected by a shaft supported by the center housing, wherein the shroud and the center housing are provided. The present invention is characterized in that positioning means are provided to determine the positions of the center housing and the shroud by fitting into the respective shrouds, and a gap is provided between the shroud and the turbine housing.

(Function) According to the housing structure of the turbocharger according to the present invention, since the shroud is supported by the center housing which maintains a relatively constant temperature, the relative position of the shroud and the turbine wheel changes depending on the temperature of the turbine housing, etc. It will not be affected. Therefore, the clearance between the outer periphery of the turbine wheel and the shroud can be maintained approximately constant regardless of the presence or absence of thermal distortion of the turbine housing, and there is no interference with the turbine wheel or an increase in the amount of exhaust gas leaking through the outer periphery clearance. , it is possible to prevent a decrease in turbine efficiency. Furthermore, since there is a gap between the turbine housing and the shroud, even if the turbine housing experiences thermal strain, the thermal strain in the turbine housing is absorbed by the gap and does not cause any strain on the shroud. Therefore, the clearance around the turbine wheel is maintained constant regardless of the presence or absence of distortion in the turbine housing, which prevents interference between the turbine wheels and a decrease in turbine efficiency due to thermal distortion of the turbine housing. It is not necessary to secure that much, and weight reduction can be achieved.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 to 3 show a turbocharger according to an embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view of the whole, FIG. 2 is a cross-sectional view taken along the line II-11 in FIG. 1, and FIG. is an enlarged sectional view of the main part.

In the figure, (11) is a compressor housing that rotatably accommodates a compressor impeller to be described later, (12) is a turbine housing that rotatably accommodates a turbine wheel to be described later, and (13) is a unit that connects the compressor impeller and the turbine wheel. The center housing supports the shaft, and the compressor casing (11) and the turbine housing (12) are the center housing (13).
are integrally joined in between. A back plate (14) is fixed to the left open end of the compressor housing (11) by bolts (15) and a mounting plate (16), and there is an axial passage (17) and a scroll passage (18) inside. )
is defined. The back plate (14) is connected to the center housing (13) by bolts (19). The left end of the axial passage (17) in the figure is the scroll passage (18).
These passages (17) and (18) communicate with the center of
A compressor impeller (21) attached to the right end of the shaft (20) in the figure is rotatably housed in the communicating portion of the shaft (20). The axial passage (17) has an intake inlet (17a) that introduces intake air at the right end in the figure, and the scroll passage (18) has an intake outlet (17a) connected upward to the combustion chamber of the engine (not shown). (not shown) is open.

The center housing (13) has two bearing parts (2
2) and (23) are formed, and these bearing parts (22)
, (23) bearing hole (22a), (
23a) respectively float bearings (24),
A shaft (20) is rotatably supported via (25). The right end of the shaft (2o) in the figure is the back plate (14
) is rotatably penetrated through the bushing (2B) and connected to the compressor impeller (21), and the left end in the figure is connected to the turbine wheel. 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 the bearing portion (2).
2), float bearing (24) above (23)
).

The oil supply passage (30) that supplies lubricating oil to (25) functions as an oil drain passage (31) that discharges lubricating oil below the bearings (22) and (23). A passageway (31) is provided with the same reference numeral as that of the passageway (31). The oil supply passage (30) includes an introduction hole (30a) whose upper end is open, and a horizontal hole (30
b), and two distribution holes (30c) and (30d) that communicate with the horizontal hole (30b) and open on the circumferential surfaces of the bearing holes (22a) and (23a), respectively. . The upper end opening of the introduction hole (30a) is connected to a lubricating oil supply source such as an oil pump (not shown), and the hole (31)
The opening at the lower end is connected to the oil pan, etc. These oil supply passages (30) and oil drainage passages (31) supply lubricating oil supplied from a lubricating oil supply source to the bearings (24),
(25) and (29) for lubrication and cooling, after which this lubricating oil is returned to the oil pan and recovered. Note that (32) is a water jacket for cooling water formed on the turbine housing (12) side of the oil supply passage (30) and oil drain passage (31), and this quarter jacket (32) has a water inlet at the bottom and a water inlet at the top. The drain is open. This quarter jacket (32) prevents heat transfer from the turbine housing (12), and also evaporates cooling water during heat soak back, and uses the heat of evaporation to cool the bearings (22) and (23).

The turbine housing (12) has stud bolts (33
) is screwed onto this stud bolt (33), and a nut (
It is fixed to the center housing (13) by a mounting plate (35) fastened to the center housing (13). This turbine housing (12) has a vane holding member (shroud) (3B) whose outer peripheral edge is sandwiched between the turbine housing (12) and the center housing (13) at the right opening end in the figure.
), and a top plate (shroud) (38) fixed to the vane holding member (36) with bolts (37) is fitted into the inner peripheral portion. The turbine housing (12) has a scroll passage (39) inside.
) and an outlet passage (40), and an exhaust inlet (39a) that opens tangentially to the scroll passage (39) and an exhaust outlet (40) that opens at the left end of the outlet passage (40). 4 (la) is formed.The central part of the scroll passage (39) and the right end part of the outlet passage (40) communicate with each other, and a shaft (20) is formed in the part where these passages (39) and (40) communicate. A turbine wheel (41) fixed to the left end of the turbine wheel is rotatably arranged.

The top plate (38) is connected to the turbine housing (12).
) at the inner end of the outlet passageway (40) of the seal ring (42).
The cylindrical part (38a) fitted through the cylindrical part (38a)
a), and a disk portion (38b) integrally extending in the radial direction from the axial center portion of the outer periphery. Cylindrical part (3
Inside 8a), the aforementioned turbine wheel (4I) is rotatably arranged around the outer circumference with a predetermined clearance, and the disc part (38b) connects the scroll passage (39) to the outer circumferential path (39b) and the inner circumferential path ( 39c). This top brake (38) is located between the disc part (38b) and the inner wall of the turbine housing (12) and the cylindrical part (38).
38a) and the inner circumferential wall of the turbine housing (12), with a slight clearance between the disk portion (38b), the vane holding member (3δ), and the heat shield plate (described later) from the turbine housing (12) side. The aforementioned bolt (37) passes through and is screwed into the vane holding member (36).
) is fixed to the vane holding member (36).

Note that the end of the bolt (37) on the center housing (13) side is welded to the end of the heat shield plate on the center housing (13) side to prevent loosening.

The vane holding member (36) includes a disk portion (36a) through which the shaft (20) rotatably passes, and a disk portion (36a) through which the shaft (20) rotatably passes.
) four wing-shaped fixed vanes (4) integrally extending from the outer periphery of the
3). A flange (36b) is integrally formed on the outer periphery of the disc portion (36a), and an annular boss (38C) is integrally formed on the end surface on the side of the center housing (13). As detailed in Figure 3, the flange (36b
) is sandwiched between the turbine housing (12) and the center housing (13) as described above, and the boss (3
6c) is fitted into an alignment hole (13a) formed in the end surface of the center housing (13) on the side of the turbine housing (13). The outer periphery of the boss (38c) fits into the inner periphery of the alignment hole (13a), and the end abuts the bottom surface of the alignment hole (13c).

Furthermore, this boss (36c) has a heat shield plate (44
) is fitted, and this heat shield plate (44) and the disc part (36a)
A heat insulating layer (44a) is formed between the two. Heat shield plate (4
4) is fixed to the vane holding member (36) by welding. This vane holding member (36) has a disc portion (36
There are clearances (59a) and (59b) between the outer circumferential wall of a) and the outer circumferential wall of the flange (38b) and the inner circumferential wall of the turbine housing (12), respectively, and the boss (3
6c) is the alignment hole (1) of the center housing (13).
3a) for concentric and axial positioning. In addition, in Fig. 1, (60a) is the center housing (1
Similarly, (aob) is a knock pin for aligning the vane holding member (36) and the top plate (38) in the rotational direction.

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. These fixed vanes (43)
In between, there are four movable vanes each having a partial arc shape (
45) are arranged, and these fixed vanes (43) and movable vanes (45) respectively lead to scroll passages (39).
) between the outer circumferential path (39t+) and the inner circumferential path (39c)
Two variable apertures (46) are arranged. Each of the movable vanes (45) has one end fixed to a pin (47) that rotatably passes through a hole (31ib) formed in the disk portion (36a) of the vane holding member (36). As the variable throttle (46) rotates, it tilts and the flow path area (
opening).

The pin (47) projects toward the center housing (13) and has an end connected to an actuator via a link mechanism (not shown), and is driven by the actuator.

This link mechanism etc. is based on the patent application filed in 1988 by the applicant.
1-125 (described in detail in the specification of No. 100, etc., so the following explanation will be omitted.

In addition, (48) is a disc-shaped shield plate whose outer peripheral edge is sandwiched between the inner peripheral end of the heat shield plate (44) and the outer peripheral wall of the center housing (13), and (49) is the turbine housing ( 1
2), and the shield plate (48), together with the aforementioned heat shield plate (44), prevents exhaust heat from being transferred to the center housing (13).

Next, the operation of this embodiment will be explained.

In this turbocharger, when the rotational speed of the engine is relatively low and the flow rate of exhaust gas is low, the movable vane (45) is positioned as shown in FIG. 2, and the variable throttle (46) is set to the minimum opening degree. Therefore, the exhaust gas introduced from the exhaust introduction port (39a) is
) through the variable aperture (46) and is accelerated to the inner circumferential path (39).
c) and creates a swivel valve in the inner circumference (39c) to drive the turbine wheel (41). Therefore, the compressor impeller (21) is rotated at high speed to pressurize the suction, ensuring a supercharging effect during low speed operation of the engine.

Further, when the rotational speed of the engine increases and the flow rate of exhaust gas also increases, the movable vane (45) is driven toward the center in accordance with the rotational speed of the engine, and the opening degree of the variable throttle (46) increases. Therefore, the flow resistance of the exhaust gas is also reduced,
Engine exhaust back pressure can be reduced. Then, as described above, the turbine wheel (4I) is driven by the exhaust gas, and the compressor impeller (21) pressurizes the intake air to perform supercharging.

On the other hand, this turbocharger has a scroll passage (39
) etc. due to the heat of the exhaust gas flowing through the turbine housing (12
) is heated and the turbine housing (12) etc. undergo thermal expansion, but the vane holding member (36) is heated by the boss (38c).
is fitted into the alignment hole (13a) of the center housing (13) and its position is determined based on the center housing (13), so it is fixed to the vane holding member (36) and the vane holding member (36). top plate (38
) is not affected by thermal expansion of the turbine housing (12) etc., and the clearance between the top plate (38) and the turbine wheel (41) is kept constant during operation when the turbine housing (12) etc. are heated. can be kept. In other words, the center housing (13) is cooled by lubricating oil and cooling water and maintained at a low temperature (approximately 300°C or less) during operation, so the thermal expansion (thermal strain) of the center housing (13) is minimal. A turbine wheel (41) supported by a shaft (20) and a center housing (13) are attached to this center housing (13).
) and the top plate (38) aligned by the vane holding member (36) hardly changes. Therefore, the top plate (3
8) and the turbine wheel (41) due to an increase in the amount of leaked exhaust gas, and the turbine wheel (41) and the top plate (38) do not interfere with each other due to a decrease in the clearance. High reliability is achieved without reducing efficiency and without interference with the turbine wheel due to misalignment.

Furthermore, in this turbocharger, since the center housing (13) has an asymmetrical shape, thermal strain becomes locally large during heating, but the outer peripheral surface of the vane storage member (36) and the turbine housing (12) There are clearances (59a) and (59b) between them, and there is also a clearance between the top plate (38) and the turbine housing (12), so these clearances (59a)
, (59b) absorbs the thermal strain of the turbine housing (12), and the top plate (38) and the vane holding member (36) are not affected by the thermal strain of the turbine housing (12). Therefore, the top plate (38) and the turbine wheel (41)
The clearance between the turbine wheel (41) and the top plate (38) is not affected by local thermal distortion of the turbine housing (12), and as described above, it is possible to prevent a decrease in turbine efficiency and interference with the top plate (38) of the turbine wheel (41). .

In the above embodiment, the vane holding member (36) and the center housing (13) are aligned by fitting the boss (38c) into the alignment hole (13a). Needless to say, the heat shield plate (44) can be fixed by welding or the like, and the heat shield plate (44) can be fitted to the vane holding member (36) for alignment. Needless to say, alignment can be achieved using the same method.

(Effects of the Invention) As explained above, according to the housing structure of the turbocharger according to the present invention, since a clearance is provided between the shroud and the turbine housing and the shroud is aligned with the center housing as a reference, the turbine housing The clearance between the turbine wheel and the shroud can be maintained constant regardless of the temperature of the turbine wheel, and a decrease in turbine efficiency and interference of the turbine wheel with the shroud due to changes in this clearance can be prevented.

[Brief explanation of the drawing]

1 to 3 show the housing structure of a turbocharger according to an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view;
FIG. 2 is a sectional view taken along arrow II-11 in FIG. 1, and FIG. 3 is an enlarged sectional view of the main part. 11... Compressor housing 12... Turbine housing 13... Center housing 13a... Alignment hole (alignment means) 20... Shaft 21... Compressor impeller 36... Vane holding member (shroud) )36c...
Boss (positioning means) 38...Scroll passage 40...Outlet passage 4
1... Turbine wheel 43... Fixed vane 4
4...Heat shield plates 55a, 55b...Clearance 60a, 60b Knock bottle procedure amendment sealing May v. 1988 Mr. Akio Kuroda, Commissioner of the Japan Patent Office: To: 5: No. 1, Patent application for indication of the case No. 1981-291178 2, Name of the invention Turbocharger housing structure 3, Relationship to the amended case Patent applicant (532) Honda Motor Co., Ltd. 4, Agent 2-4-5 Azabudai, Minato-ku, Tokyo No. 6, Subject of amendment 7, Contents of amendment (1) The detailed description of the invention is corrected as follows. (a) In the 19th line of page 2 of the specification, the phrase ``heat-resistant steel such as stainless steel'' is corrected to ``heat-resistant material.'' (b) The phrase "oil pan" on page 10, line 1 O of the specification is corrected to "oil pan, etc." (c) Page 13, line 13 of the specification is amended as follows. "The end surface of the flange (38b) on the center housing side is in contact with the corresponding center housing." (d) The 15th line of page 18 of the specification is corrected as follows. "The vane holding member (36) will not be distorted. This allows the movable vane (45) to operate reliably without being affected by thermal distortion." (E) Specification No. 1
Correct the first line of page 9 as follows. Furthermore, the clearance between the movable vane (45) and the vane holding member (36) or the top play h (38) is not affected by heat, and the movable vane (45)
It is also possible to prevent a decrease in turbine efficiency, such as by minimizing exhaust gas leaks when the engine is at its peak. (f) The 6th line of page 19 of the specification is amended as follows. ``Incorporate a heat insulator like the one seen on the compressor side, and fit this heat shield plate (44) to the vane holding member (36)'' (2) See Figures 1 and 3 of the drawings in the attached sheet. correct.

Claims (1)

[Scope of Claims] A compressor housing in which a compressor impeller is housed and a turbine housing in which a turbine wheel is housed are joined through a center housing, and at least one shroud is disposed within the turbine housing, and the shroud is connected to the turbine wheel. In a turbocharger that surrounds a wheel and connects the turbine wheel and the compressor impeller by a shaft supported by the center housing, the shroud and the center housing are respectively fitted to adjust the positions of the center housing and the shroud. A housing structure for a turbocharger, characterized in that a positioning means for determining the position is provided, and a gap is provided between the shroud and the turbine housing.