JPH033052B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to a variable displacement turbocharger that configures a variable exhaust throttle by a movable vane and a fixed vane, and more particularly, to a member that supports a drive shaft of the movable vane. The present invention relates to a variable displacement turbocharger in which a fixed vane is provided to facilitate adjustment of a gap between a movable vane and a fixed vane.

(Prior technology) The variable displacement turbocharger was developed in
As described in Publication No. 7653, a plurality of movable vanes are arranged in an annular manner at the throat facing the outer periphery of the turbine wheel to form a variable exhaust throttle, and the movable vanes are driven when the engine is operating at low speed. It was known to reduce the opening of the variable aperture. However, in such conventional variable displacement turbochargers, 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 vanes. Accurate control of the opening was difficult in the low opening range of the variable aperture.

Therefore, in Japanese Patent Application No. 124996/1988 filed on May 30, 1985, the present applicant has proposed a variable displacement turbocharger that can accurately control even the low opening of the variable throttle. This variable displacement turbocharger has a turbine housing surrounding a turbine wheel with a top plate and a back plate, a fixed vane on the top plate, and a movable vane on a drive shaft supported by the back plate. The fixed vane and the movable vane are arranged adjacent to the outside of the throat facing the outer periphery of the turbine wheel to form a variable exhaust throttle.

(Problems to be Solved by the Invention) However, in the variable displacement turbocharger according to the applicant's earlier application mentioned above, the fixed vanes are formed on the top plate, and the movable vanes are separate from the top plate. It is supported by the back plate of the body, and assembly tolerances are allowed between the top plate and the back plate, so the gap (back clearance) between the supporting end of the movable vane to the drive shaft and the fixed vane can be accurately determined. There were problems in that it was difficult to set, resulting in malfunction of the movable vane or a decrease in turbine efficiency. In other words, it is desirable that the back clearance be small in order to prevent exhaust leaks and improve turbine efficiency, but if the back clearance is small, the movable vanes may interfere with the fixed vanes when the top plate etc. are heated. This may prevent smooth operation of the movable vane.

The present invention was made in view of the above-mentioned problems, and provides a variable displacement turbocharger in which both a movable vane and a fixed vane are supported on the same base plate, allowing accurate setting of back clearance and reducing turbine efficiency. The purpose is to prevent the movable vane from malfunctioning.

(Means for Solving the Problems) The present invention includes a base plate and a top plate disposed within a turbine housing to define a space in which a turbine wheel is housed, and a compressor housing connected to the turbine housing via a center housing. A compressor impeller housed in the compressor housing and a turbine wheel housed in the space are connected by a shaft supported by the center housing, and a shaft in the space is connected to the turbine housing. An exhaust introduction passage that opens on the outer periphery of the turbine wheel is formed, and a plurality of fixed vanes and movable vanes are alternately arranged adjacent to each other at the opening of the exhaust introduction passage to the space to constitute a variable exhaust throttle. In the variable capacity turbocharger that adjusts the opening degree of the variable throttle by driving the movable vane, the movable vane is integrally coupled to a drive shaft supported by the base plate, and the fixed vane is coupled to the base plate. The gist is that it has been permanently installed.

(Function) According to the variable displacement turbocharger according to the present invention, the movable vane is attached to the drive shaft supported by the base plate, and the fixed vane is fixed to the base plate. The relative position with the fixed vane does not shift and the back clearance can be set accurately, ensuring smooth operation of the movable vane, and
Decrease in turbine efficiency can be prevented, and furthermore, the rear clearance can be easily adjusted during assembly.

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

1 to 3 show a variable displacement turbocharger according to an embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view, FIG. 2 is a cross-sectional view taken along the - arrow in FIG. It is a front view of a plate.

In the figure, reference numeral 11 denotes a compressor housing that rotatably accommodates a compressor impeller, which will be described later.
Reference numeral 2 indicates a turbine housing that rotatably accommodates a turbine wheel, which will be described later. Reference numeral 13 indicates a center housing that supports a shaft that connects the compressor impeller and the turbine wheel. are integrally joined in between. The compressor housing 11 has a back plate 14 with bolts 15 and a mounting plate 16 at the left open end in the figure.
An axial passage 1 and a scroll passage 18 are defined therein. 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 compressor impeller 21 attached to the right end of the shaft 20 in the figure communicates with the center of the scroll passage 18.
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 (not shown) opened upward that communicates with the combustion chamber of the engine (not shown). are doing.

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. 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 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. The opening end of the turbine housing 12 on the right side in the figure is closed by a vane holding member (base plate) 36 whose outer peripheral edge is sandwiched between the turbine housing 12 and the center housing 13. A top plate 38 fixed by bolts 37 fits into the inner circumference. The turbine housing 12 has a scroll passage 39 and an outlet passage 40 defined therein, and an exhaust inlet 39a opening tangentially to the scroll passage 39 and an exhaust exhaust opening opening at the left end of the exit passage 40. An outlet 40a is 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 arranged within 8a with a predetermined clearance, and the disc portion 38b divides the scroll passage 39 into an outer circumferential path 39b and an inner circumferential path 39c. As shown in detail in FIG. 3, this top plate 38 is formed with a hole 37g through which the bolt 37 described above passes, and also has a step-shaped relief part 38g that serves as a fully closed position stopper for the movable vane, which will be described later. is formed. A part of the relief portion 38g extends along the outer circumferential shape (circle) of the support end of the movable vane, and has a predetermined clearance (usually 0.25 mm) between the relief portion 38g and the support end.
It is defined by a step wall 38h having a diameter of about mm),
This step wall 38h extends along the wing shape of the movable vane and is continuous with a step wall 38i that functions as a stopper for the movable vane. In addition, the step wall is 38g
is formed so that the clearance between it and the movable vane 45 described above is larger than the back surface clearance described later. This top plate 38
is the disk portion 38b from the turbine housing 12 side.
And it is fixed to the vane holding member 36 by the aforementioned bolt 37 which passes through the vane holding member 36 and is screwed into the vane holding member 36 .

The vane holding member 36 includes a disk portion 36a through which the shaft 20 rotatably passes, and four fixed vanes 43 that extend integrally from the outer peripheral portion of the disk portion 36a toward the top plate 38 in the axial direction. It consists of This vane holding member 36 has a heat shield plate 44 on the end face on the center housing 13 side.
is fitted and a heat insulating layer 44a is formed between the disk portion 36a and the disk portion 36a.
is formed, and a stepped wall 36g (see FIG. 2) which functions as a stopper for the movable vane, which will be described later, is formed on the surface of the top plate 38 side where the fixed vane 43 is formed, along the wing shape of the movable vane. . The bolts 37 mentioned above protrude from the surface of the heat shield plate 44 on the center housing 13 side, and the protruding ends of the bolts 37 and the surface of the heat shield plate 44 on the center housing 13 side are welded to prevent the bolts 37 from loosening. Prevented.

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 partially arcuate movable vanes 45 are arranged between these fixed vanes 43, and these fixed vanes 43 and movable vanes 45 connect the outer circumferential path 39b and the inner circumferential path 39c of the scroll passage 39. A variable aperture 46 is configured in between. A substantially half-moon-shaped notch 43a is formed in the fixed vane 43 on the support end side of the movable vane 45, and receives the support end of the movable vane 45. This notch 43a is the movable vane 45
A specified back clearance (usually
It is partially defined by a partial circular arc wall 43b that is concentric with and has a substantially similar shape to the shape (circular) of the support end (approximately 0.1 [mm]), and this partial circular arc wall 43b is continuous with the step wall 36g described above. ing. Movable vane 45
are the disk portions 36a of the vane holding member 36, respectively.
A support end is fixed to a pin 47 (drive shaft) that rotatably passes through a hole formed parallel to the shaft 20, and tilts as the pin 47 rotates to change the flow path area (opening) of the variable throttle 46. degree). The movable vane 45 sets the variable aperture 46 to the minimum opening degree at a position where it abuts the step wall 38i of the top plate 38 and the step wall 36g of the vane holding member 36, and tilts inward from this position to make the movable vane 45 variable. Increase the opening degree of the diaphragm 46. Although not shown, the end of the pin 47 protruding toward the center housing 13 is connected to the actuator via a link mechanism disposed 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 a mounting stud screwed onto the turbine housing 12. is a bolt,
The shield plate 48, together with the heat shield plate 44 described above, 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 between the step walls 36g and 3 as shown in FIG.
8i, and the variable diaphragm 46 is set to the minimum opening degree. Therefore, the exhaust gas introduced from the exhaust gas introduction port 39a is transferred to the outer peripheral path 39b of the scroll passage 39.
is accelerated through the variable aperture 46 and passes through the inner circumferential path 39c.
The liquid flows into the inner peripheral path 39c and generates a swirling flow to drive the turbine wheel 41. Therefore, the compressor impeller 21 is rotated at high speed to pressurize the intake air, thereby 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 waste gate or control valve. can do. Then, as mentioned above, the turbine wheel 4
1 is driven by exhaust gas, and a compressor impeller 21 pressurizes intake air to perform supercharging.

On the other hand, in this variable displacement turbocharger, a fixed vane 43 is integrally formed on the end surface of the vane mounting member 36 on the top plate 38 side, and a movable vane 45 is provided with a pin that passes through a hole 36b formed in the vane mounting member 36. 47 is fixedly installed. Therefore, the relative position between the fixed vane 43 and the movable vane 45 is not affected by assembly tolerances of parts, and the back clearance between the fixed vane 43 and the movable vane 45 can be set accurately. It is also easy to adjust the rear clearance. Therefore, the back clearance can be set to the optimum value,
Exhaust leakage can be minimized to prevent a decrease in turbine efficiency, and interference due to thermal expansion during hot conditions can be prevented to ensure smooth operation of the movable vanes.

Furthermore, in this variable displacement turbocharger, the vane mounting member 3 of the top plate 38 is
A concave relief portion 38g for guiding the movable vane 45 is formed on the end face of the movable vane 45, and this relief portion 38g is defined by a step wall 38h having a clearance between it and the outer peripheral edge of the support end of the movable vane 45. There is.
The step wall 38h is formed such that the clearance between it and the outer periphery of the support end of the movable vane 45 is larger than the back clearance. Therefore, even if the relative positions of the top plate 38 and the vane mounting member 36 deviate due to assembly tolerances, the movable vane 45 will not interfere with the step wall 38h of the top plate 38, and the movable vane 45 will not operate smoothly. Secured.

(Effects of the Invention) As explained above, according to the variable displacement turbocharger according to the present invention, since the base plate supports both the fixed vane and the drive vane that constitute the variable exhaust throttle, the fixed vane and the movable vane The back clearance can be set accurately to improve turbine efficiency without interfering with the smooth operation of the movable vane, and furthermore, the back clearance can be easily adjusted during assembly.

[Brief explanation of drawings]

1 to 3 show a variable displacement turbocharger according to an embodiment of the present invention, in which FIG. 1 is a longitudinal view, FIG. 2 is a sectional view taken along the - arrow in FIG. 1, and FIG. 3 is a top view. It is a plate front view. 11... Compressor housing, 12... Turbine housing, 13... Center housing,
20...shaft, 21...complex impeller, 36...vane holding member (base plate),
36g...Step wall, 38...Top plate, 3
8g... Relief portion, 38h... Step wall, 39... Scroll passage (exhaust introduction passage), 41... Turbine wheel, 43... Fixed vane, 45... Movable vane, 46... Variable throttle, 47... Pin (drive shaft).

Claims (1)

[Scope of Claims] 1. A base plate and a top plate are disposed within a turbine housing to define a space in which a turbine wheel is housed, and a compressor housing is coupled to the turbine housing via a center housing, so that the compressor A complex impeller housed in a housing and a turbine wheel housed in the space are connected by a shaft supported by the center housing, and an opening is provided in the turbine housing on the outer periphery of the turbine wheel in the space. a plurality of fixed vanes and movable vanes are alternately arranged adjacent to each other at the opening of the exhaust introduction passage to the space to form a variable exhaust throttle; The variable displacement turbocharger adjusts the degree by driving the movable vane, characterized in that the movable vane is integrally coupled to a drive shaft supported by the base plate, and the fixed vane is fixed to the base plate. Variable displacement turbocharger. 2. The variable displacement turbocharger according to claim 1, wherein the base plate and the top plate are joined by bolts passing through the top plate and the base plate from the top plate side.