JPS63183206A - variable capacity turbine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a variable displacement turbine used in a turbocharger, etc., and more specifically, the present invention relates to a variable displacement turbine used in a turbocharger, etc., and more specifically, the invention relates to a variable displacement turbine that is applied to a turbocharger, etc. The present invention relates to a variable capacity turbine that prevents movable vanes from biting against the wall surface of an exhaust passage at times.

(Prior Art) A variable displacement turbine is used as an exhaust turbine of a variable displacement turbocharger, and one such as described in Japanese Patent Publication No. 38-7653 is known. This variable displacement turbocharger has multiple movable vanes arranged in the throat facing the outer periphery of the turbine wheel to form a variable exhaust throttle.These movable vanes are driven by an actuator to make the throttle variable during low-speed engine operation. This is to increase the supercharging effect when the engine is running at low speeds. However, in such a variable capacity turbine, the variable throttle is configured in the gap between the movable vanes, so the opening degree of the variable throttle is greatly affected by even a slight deviation in the tilt angle of the movable vane, and the It was difficult to accurately manage the opening in the opening range.

Therefore, in the specification of Japanese Patent Application No. 61-124996 filed on May 30, 1985, the present applicant has proposed a variable capacity turbine that can accurately control even the low opening range of the variable throttle. . This variable capacity turbine has a base plate and a top plate provided in the turbine housing to surround a turbine wheel, and a movable vane and a fixed vane are respectively provided on the outer periphery of the turbine wheel and on walls facing parallel to the base plate and the top plate. It is installed adjacently to form a variable exhaust throttle.

(Problem to be solved by this invention) However,
In the above-mentioned variable displacement turbine applied by the present applicant, the movable vane has its base end connected to a drive shaft passing through the base plate, and can tilt between the parallel opposing wall surfaces of the base plate and the top plate. Therefore, if the drive shaft of the movable vane tilts due to thermal strain, etc.,
There is a problem in that when the parallelism of the wall surfaces of the base plate and the top plate decreases, or when the wall surfaces are distorted, the movable vanes may get stuck on the wall surfaces, preventing smooth operation.

This invention was made in view of the above-mentioned problems, and aims to provide a variable capacity turbine that prevents movable vanes from seizing when thermal strain occurs, and to ensure smooth operation thereof. .

(Means for Solving the Problems) This invention forms an exhaust passage in the turbine housing that guides exhaust gas to the turbine wheel, and movable vanes are tiltably disposed between partition walls facing substantially parallel to the exhaust passage. in a variable capacity turbine in which a drive shaft passing through the partition wall is coupled to the movable vane to drive the movable vane, the end opposite to the end of the movable vane on the coupling side with the drive shaft; The gist is that the edge of the side end is tapered so as to reduce in the width direction of the movable vane from the coupling part of the drive shaft toward the tip of the movable vane.

(Function) According to the variable displacement turbine according to the present invention, the edge of the movable vane at the side end opposite to the end connected to the drive shaft is reduced in the width direction from the joint to the drive shaft toward the tip. The movable vane is formed into a tapered shape, and a gap is formed between the connecting end of the movable vane and the picture wall. Therefore, even if the drive shaft of the movable vane is tilted, the parallelism of the painting wall is decreased, or the painting wall is distorted due to thermal effects, the movable vane will not bite into the painting wall and will smoothly move. This ensures proper operation.

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

1 to 3 show a variable capacity turbine according to an embodiment of the present invention applied to a turbocharger, and
The figure is a vertical cross-sectional view of the turbocharger, and Figure 2 is I of Figure 1.
A sectional view taken along arrows I-II, and FIG. 3 is an enlarged sectional view of main parts.

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 (1) 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 communicates with the center of the scroll passage (18), and a shaft (20) is attached to the right end of the shaft (20) in the part where these passages (17) and (18) communicate. A compressor impeller (21) is rotatably housed. 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 (20) in the figure is the back plate (14).
) is rotatably penetrated through the bush (26) 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 (3G) 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 (3od) communicating with the horizontal hole (30b) and opening at the sides 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 (3) supply lubricating oil supplied from a lubricating oil supply source to bearings (24), (
25) and (29) for lubrication and cooling, and then the lubricating oil is returned to the oil pan and recovered. In addition, (32) is a cooling water quarter jacket formed on the turbine housing (12) side of the oil supply passage (30) and oil drain passage (31), and this water jacket (32) has a water inlet at the bottom and a water inlet at the top. The drain is open. This water 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 (base plate) whose outer peripheral edge is sandwiched between the turbine housing (12) and the center housing (13), whose opening end on the right side in the figure
36), and the vane holding member (36)
(top brake secured by bolts (37) to
(3B) is fitted to the inner circumference. The turbine housing (12) has a scroll passage (39) and an outlet passage (40) defined therein, and a scroll passage (39).
) is an exhaust inlet port (39a) that opens tangentially to the
) and an exhaust outlet (40a) that opens at the left end of the outlet passage (40). Scroll passage (39)
The central part of the shaft (20) communicates with the right end of the outlet passageway (40), and a turbine wheel (4
1) are arranged rotatably.

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 axially central portion of the outer periphery of (a). Cylindrical part (38
The above-mentioned turbine wheel (41) is rotatably disposed within a) with a predetermined clearance, and the disc portion (38b) connects the scroll passage (39) with the outer peripheral path (39).
b) and an inner circumferential path (39c).

As shown in FIG. 3, this top plate (38) has a step wall (38h) formed on the end face of the disk portion (38b), which serves as a fully closed position stopper for the movable vane, which will be described later. This step wall (38h) partially extends along the blade shape of the outer peripheral edge of the movable vane. This top plate (
38) is a disk portion (
38b) and the aforementioned bolt (37) which passes through the vane retaining member (36) and is screwed into the vane retaining member (36).
It is fixed to the vane holding member (36) by.

The vane holding member (36) includes a disk portion (36a) through which the shaft (20) rotatably passes, and the disk portion (36a).
It consists of four fixed vanes (43) that extend integrally from the outer peripheral part of the top plate (38) in the axial direction toward the top plate (38). The disk portion (36a) is located parallel to the disk portion (38b) of the aforementioned top plate (38). A heat shield plate (44) is fitted onto the end face of the vane holding member (36) on the center housing (13) side, and a heat insulating layer (44a) is formed between the vane holding member (36) and the disc portion (38a).
Additionally, the top plate (
A stepped wall (368N, see FIG. 2) which functions as a stopper for the movable vane (described later) is formed on the side surface of the movable vane along the wing shape of the movable vane. Note that the above-mentioned bolts (
37) protrudes, and the protruding end of this bolt (37) is welded to the surface of the heat shield plate (44) on the center housing (13) side, thereby preventing the bolt (37) from loosening.

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 (
The fixed vane (43) and the movable vane (45) create a variable throttle (4) between the outer circumferential path (39b) and the inner circumferential path (39c) of the scroll passage (39).
6) is configured. The movable vane (45) has a pin (47) (drive shaft) fixed to the base end thereof, which rotatably passes through the disk portion (3aa) of the vane holding member (36).

This movable vane (45), as shown in detail in FIG.
A boss portion (45a) is provided coaxially with the pin (47) on the vane holding member (36) side at the base end, and a vane holding member is provided on the edge of the top plate (38) side from the base end toward the tip. Tapered part (45b) that slopes toward the member (36) side
is formed. The height of the boss portion (45a) of the movable vane (45) is set so that the edge on the vane holding member (36) side can come into contact with the step wall (36g) during hot and cold conditions. (38g) is formed smaller,
Similarly, the inclination of the tapered portion (45b) is set so that the tip edge on the top plate (38) side can come into contact with the step wall (38h) even when cold, and these boss portions (45a)
By forming the taper part (45b) as described above, each step wall (36g) at the minimum opening of the variable aperture (46)
, (38h) prevents galling (described later) while suppressing leakage of exhaust gas from between. This movable vane (45) tilts with the rotation of the bottle (47) to change the flow path area (opening degree) of the variable throttle (46), and is attached to the step wall (36g) of the vane holding member (36). The variable diaphragm (46) is set to the minimum opening degree at the abutting position, and the opening degree of the variable diaphragm (46) is increased by tilting inward from this position.

Although not shown, the pin (47) is attached to the center housing (1
3) The end protruding toward the side is connected to the actuator via a link mechanism arranged between the center housing (13) and the vane holding member (36).

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 (
12), and the shield plate (48), together with the aforementioned heat shield plate (44), prevents heat from the exhaust gas 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) moves toward the step wall (38g) as shown in FIG.

(38i), and the variable diaphragm (46) is set to the minimum opening degree. Therefore, the exhaust gas introduced from the exhaust inlet port (39a) is
9b) through the variable aperture (46) and is accelerated to the inner circumferential path (
39c) and generates a swirling flow within the inner circumferential path (39c) to drive the turbine wheel (41). Therefore, the compressor impeller (21) is rotated at high speed to pressurize the intake air, 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, it is possible to ensure an appropriate supercharging effect depending on the operating condition, and the flow resistance of the exhaust gas is also reduced.Since the opening area can be made large, the exhaust back pressure of the engine can be reduced without the need for a special wastegate or control valve. can do. Then, as described above, the turbine wheel (41) is driven by the exhaust gas, and the compressor impeller (21) pressurizes the intake air to perform supercharging.

On the other hand, this variable capacity turbocharger has pins (47
) and the vane holding member (36) that supports both ends of the heat shield plate (
44) and the top plate (38) have different temperatures between the outer and inner circumferential portions, and these bearing portions and the top plate (38) are prone to thermal strain. In particular, the vane holding member (36) is a heat shield plate (44).
Since the pin (47) is at a high temperature compared to Displace. However, since a tapered part (45b) is formed at the edge of the movable vane (45) on the top plate (38) side and there is a gap between the movable vane (45) and the top plate (38), the top plate ( 38) or the pin (47) is distorted, the movable vane (45) will not move against the top plate (38) or the vane mounting member (36).
) to ensure smooth operation.

(Effects of the Invention) As explained above, according to the variable displacement turbine according to the present invention, the movable vane is formed such that the edge opposite to the edge coupled to the drive shaft is tapered and inclined. Therefore, even if the picture wall surrounding the movable vane or the like is thermally distorted, the movable vane will not bite into the surrounding wall surface, ensuring smooth operation.

[Brief explanation of the drawing]

1 to 3 show a variable displacement turbine according to an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of a turbocharger, FIG. 2 is a sectional view taken along the line II-II in FIG. Third
The figure is an enlarged sectional view of the main part. 12... Turbine housing 36... Vane holding member 38... Top plate 38h... Step wall 39...
...Scroll passage (exhaust introduction passage) 41...Turbine wheel 43...Fixed vane 45...Movable vane 45
a...Boss part 45b...Tapered part 46...
・Variable aperture 47...Pin (drive shaft) Fig. 2

Claims (1)

[Claims] An exhaust passage that guides exhaust gas to the turbine wheel is formed in the turbine housing, and movable vanes are tiltably arranged between substantially parallel opposing walls of the exhaust passage to constitute a variable exhaust throttle. and in a variable capacity turbine in which a drive shaft passing through the partition wall is coupled to the movable vane to drive the movable vane, an edge of the movable vane at a side end opposite to a coupling side end to the drive shaft; 1. A variable capacity turbine, characterized in that the blade is tapered so as to decrease in the width direction of the movable vane from the joint portion with the drive shaft toward the tip of the movable vane.