JPS62282128A - Variable capacity turbine - Google Patents

Abstract

PURPOSE:To prevent resistance loss with respect to fluid from increasing even though the inflow amount of fluid is small, by forming a blade profile section in which a stationary vane and a movable vane are substantially continuous when a nozzle falls in a narrowest condition. CONSTITUTION:when the rotational speed of an engine is low so that the flow rate of exhaust gas is small, a movable vane 34 is closed as shown by the solid line. In the full closed condition a pair of stationary vanes 29 and a movable vane 34 form a blade profile having its outer peripheral surface which is smoothly continuous aud therefore, fluid flowing into from a scroll passage 21 is led smoothly to a nozzle section. When the rotational speed of the engine increases so that the effect of supercharge is sufficient, the movable vane 34 is tilted inward an shown by a phantom line.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a variable displacement radial turbine, and particularly to a variable displacement turbine suitable as an exhaust turbine in a turbocharger.

<Prior art> In a radial turbine used as an exhaust turbine of a turbocharger, it is sometimes desired to maintain a supercharging effect even in a region where the engine rotational speed is low. By narrowing the passageway upstream of the wheel, the fluid inflow velocity may be increased. However, if the passage is narrowed like this,
The inlet pressure of the turbine, that is, the back pressure against the exhaust gas of the engine increases, causing a problem that reduces the efficiency of the engine.

Therefore, as described in Japanese Patent Publication No. 38-7653, a plurality of movable vanes are arranged in an annular manner at the throat facing the outer periphery of the turbine wheel, and by tilting these movable vanes, a structure is created between the vanes. If the opening area of the nozzle is changed, the supercharging effect can be ensured even in the low speed range of the engine, and the back pressure against the engine exhaust gas can be kept small in the medium to high speed range of the engine. be able to. However, according to the above configuration, since these vanes are arranged in a region where the fluid velocity is relatively high, the resistance loss of the fluid tends to be relatively large, which reduces the efficiency of the turbine. There is.

In addition, since the nozzle is formed between adjacent movable vanes, the nozzle opening area can change significantly due to a slight deviation in the tilting angle of the vane, especially in areas where the nozzle opening area is small. There is a problem with the control accuracy. Particularly when such turbines are used as exhaust turbines in turbochargers, it is difficult to reliably adjust these movable vanes because they are exposed to a high temperature exhaust gas stream. .

As disclosed in Japanese Unexamined Patent Publication No. 53-136113, there is also a structure in which the cross-sectional area of the scroll passage can be varied by tilting a flap that forms part of the wall of the scroll passage of the turbine casing. It is publicly known. Although this type of variable nozzle structure has a simple structure and can adjust the velocity of fluid flowing into the turbine wheel with relatively little resistance loss, the variable range is not necessarily wide enough. In addition, especially when the flap opening degree is large, the flow of fluid toward the turbine wheel is disturbed, resulting in uneven flow velocity distribution, which reduces the efficiency of the turbine.

<Problems to be solved by the invention> In the variable displacement turbine as described above, in order to secure supercharging capacity in the high speed range and improve supercharging efficiency in the low speed range, it is necessary to close the vanes. An important point is how to increase turbine efficiency.

In view of the problems of the prior art and the knowledge of the inventor,
The main object of the present invention is to be able to operate without increasing resistance loss to the fluid even when the number of fluid inflows is small;
Moreover, it is an object of the present invention to provide a variable capacity turbine that can be controlled with high precision.

<Means for Solving the Problems> According to the present invention, such an object includes a turbine wheel, a turbine scroll formed on the outer periphery of the turbine wheel, and a turbine scroll formed on the outer periphery of the turbine wheel. A variable capacity turbine in which variable nozzles consisting of arcuate vanes are arranged annularly on a certain outer circumference,
The arcuate vane is composed of a fixed vane and a movable vane that are divided into parts, and the movable vane tilts inward from the circumference, thereby creating an arc between the fixed vane and the movable vane that face each other. The fixed vane and the movable vane form a substantially continuous airfoil cross section when the nozzle is in its narrowest state. This is achieved by providing a variable displacement turbine with the following characteristics:

<Function> In this way, by fixing one of the vanes forming the variable nozzle and moving the other, the rigidity of the nozzle can be easily increased, and the stability of control in the low speed range can be improved. .

Moreover, by smoothing the outer circumferential surface of the vane especially in the low speed range, it is possible to enhance the rectifying effect and further improve efficiency.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show an engine turbocharger to which a variable capacity turbine according to the present invention is applied.

This turbocharger has a casing consisting of a compressor casing 1 forming a scroll of the compressor portion, a back plate 2 closing the back side of the compressor casing, and a casing that pivotally supports the main shaft of the turbocharger A-jar and lubricates the bearing. Lubricating part casing 3 with built-in structure
and a turbine casing 4 forming a scroll of the turbine section.

A scroll passage 5 and an axial passage 6 are formed inside the compressor casing 1, and the compressor is located in the center of the scroll passage 5 and adjacent to the inner end side of the axial passage 6. A wheel 7 is provided. The compressor wheel 7 is attached to one end of a main shaft 8 of a turbocharger rotatably supported in the center of the lubricating part casing 3 in a manner described later.

On the compressor side, the scroll passage 5 constitutes an intake outlet passage and the axial passage 6 constitutes an intake inlet.

The compressor casing 1 and the back plate 2 have a ring member 9
The compressor casing 1 is integrated by screwing bolts 10 onto the outer circumferential portion of the compressor casing 1 via the lubrication portion casing 3 to the central portion of the back plate 2.

Bearing hole 11.1 formed inside the lubricating part casing 3
2, the main shaft 8 is pivotally supported by the radial bearing metal 13 as described above. Further, a thrust bearing metal 14 is sandwiched between the back plate 2 and the end face of the lubricating part casing 3, and a collar 15, a thrust bearing metal 14, a bushing 16, a compressor wheel 7 in this order, and screwing the nut 18 onto the threaded portion 17 cut into the compressor side end of the main shaft 8, the main shaft 8 is supported in the thrust direction and the compressor wheel 7 is mounted. Note that the collar 15 functions as a spacer for setting the clamping pressure of the thrust bearing metal 14.

When tightening the nut 18, by grasping the hexagonal cross section 19 provided in the free play part of the threaded part 17 with another tool, it is possible to prevent the main shaft 8 from rotating together, and also to prevent the main shaft 8 from rotating at the same time. The inconvenience of applying excessive torsional force is avoided.

The turbine casing 4 has a scroll passage 21 therein and an inlet opening 21a thereof which opens in the tangential direction.
an axially extending outlet passage 22 and an opening 22 thereof;
A is defined.

A back plate 23 is sandwiched between the turbine casing 4 and the lubricating part casing 3, with a flange 23a projecting outward from the outer periphery of the back plate 23. The connection between the turbine casing 4 and the lubricating part casing 3 is achieved by fastening a nut 26 to a stud bolt 24 screwed onto the side of the turbine casing 4 via a ring member 25, so that the outer circumference of the turbine casing 4 is and the ring member 25, the outer periphery of the lubricating part casing 3 and the outward flange 2 of the back plate 23
3a.

A fixed vane member 27 is disposed at the center of the scroll passage 21 to partition the inside of the scroll passage into an outer circumferential passage 21b and an inflow passage 21G. This fixed vane member 27 is
A cylindrical portion 28a formed at the center, and a disk portion 2 formed radially outward from an axially intermediate portion of the cylindrical portion 28a.
8b, and a fixed vane 29 that protrudes along the axial direction from the outer circumference of the disc part toward the lubricating part casing 3, and is formed on the other end side of the main shaft 8 inside the cylindrical part 28a. The turbine wheel 30 is received therein. The cylindrical portion 28a is fitted into the inner end of the outlet passage 22 via a metal seal ring 31, and the fixed vane 28a is fitted into the inner end of the outlet passage 22 via a metal seal ring 31.
The axial ends of 9 are connected to the back plate 23 by bolts 32.

As shown in FIG. 2, four fixed vanes 29 are formed on the outer periphery of the fixed vane member 27 so as to concentrically surround the turbine wheel 30. These fixed vanes 29 each have a partial arc shape, and are provided at equal widths and equal intervals along the circumferential direction. The space between the fixed vanes 29 and the earth is opened and closed by a movable vane 34 fixed to the free end of a pin 33 rotatably attached to the back plate 23. These movable vanes 34 are
It has an arc shape with the same curvature as the two fixed vanes, and is located on approximately the same circumference. In addition, these movable vanes 3
4 is located close to the circumferential end edge of the corresponding fixed vane 29 (it is pivoted in the left position and can be tilted only towards the inside of the circumference, and is in the fully open state). In this case, both the vanes 29 and 34 are formed in a continuous airfoil shape.Therefore, these fixed vanes 29 and
The corresponding movable vanes 34 form the leading and trailing edge portions of the four vanes for the fluid flowing in the outer peripheral path 21b of the scroll passage 21, respectively. The bins 33 that support these movable vanes 34 are each connected to an actuator having an appropriate structure (not shown) through appropriate links @35, and the inclination angle of these movable vanes 34 is controlled by a separate control signal. is adjusted.

Further, a shield plate 36 extending to the back of the turbine wheel 30 is sandwiched between the back plate 23 on the turbine side and the lubricating part casing 3, so that the heat of the exhaust gas flowing through the exhaust turbine part is transferred to the lubricating part casing 3. This prevents the heat from being transmitted to the inside of the coushing 3.

In addition, in order to prevent exhaust gas from the turbine side from leaking toward the inside of the lubricating part casing 3, an annular groove that functions as a labyrinth groove is provided in the part of the main shaft 8 that passes through the center hole 37 of the lubricating part casing 3. The groove 38 is stepped.

Next, the lubrication system of this turbocharger will be explained.

A lubricating oil introduction hole 40 is bored in the upper end of the lubricating part casing 3 in FIG.
The oil is supplied to the radial bearing metal 13 and the thrust bearing metal 14 through a lubricating oil passage 41 bored inside the radial bearing metal 13 and thrust bearing metal 14. The lubricating oil discharged from each lubricating part is discharged from a lubricating oil outlet 42 defined in the lubricating part casing 3, and is collected in an oil sump (not shown).

In particular, in order to prevent the lubricating oil supplied to the thrust bearing metal 14 from adhering to the outer circumferential surface of the bushing 16 and flowing into the compressor side, the outer circumferential surface of the bushing 16 is inserted into the center of the back plate 2 through the seal ring 43. It passes through the hole 44, and a guide plate 45 is sandwiched between the back plate 2 and the thrust bearing metal 14, with a bushing 16 inserted through the hole provided at the center thereof. Further, the lower end portion of this guide plate 45 is formed into a curved shape.

Therefore, the lubricating oil flowing out from the thrust bearing metal 14 is thrown off by the centrifugal force from the outer peripheral surface of the bushing 16, is caught by the guide plate 45, and is returned to the oil sump.

Next, the operation of this embodiment will be explained.

When the engine speed is low and the exhaust gas flow rate is relatively small, the movable vane 34 is closed, as shown by the solid line in FIGS. 2 and 3, so that the fixed vane 29 is The gap between the nozzle formed in the lap between the edge and the return edge of the movable vane 34 is set to the smallest gm
Make it so that it is in. Therefore, the exhaust gas is throttled and accelerated to the maximum extent by this nozzle, and the fixed vane member 27
Since the exhaust flow reaches the turbine wheel 30 after becoming a swirling flow in the inflow passage 21C between the exhaust flow and the turbine wheel 31, the exhaust flow is speeded up by hO and drives the turbine wheel 31, and in the low speed range of the engine. It is also possible to ensure the supercharging effect.

When the rotational speed of the engine increases and the supercharging effect becomes sufficient, the movable vane 3
4 inward, fixed vane 29 and movable vane 3
The size of the nozzle defined between 4 and 4 is increased. As a result, the exhaust flow is not accelerated and reaches the turbine wheel 30 with relatively little resistance in the flow path, making it possible to reduce the exhaust back pressure to the engine.

As clearly shown in FIG. 3, in the fully open state, the pair of fixed vanes 29 and the movable vanes 34 have a smoothly continuous outer peripheral surface in the shape of an airfoil, and the outer peripheral path 21b of the scroll passage 21 The fluid flowing in from the nozzle can be guided very smoothly to the nozzle part.

<Effects of the Invention> As described above, according to the present invention, it is possible to minimize the resistance loss of the fluid flowing into the turbine especially when the flow rate is small, and moreover, it is possible to suppress harmful stress on the movable vane due to turbulence etc. Since this can be avoided, controllability of a turbocharger etc. can be improved, and turbine efficiency can be improved, and particularly when applied to a turbocharger, it can have a great effect on improving engine performance.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a turbocharger to which a variable displacement turbine according to the present invention is applied. FIG. 2 is a view taken from line If-n in FIG. 1 when looking at the turbine casing side. Figure 3 is an enlarged view of the vane section. 1... Compressor casing 2... Back plate End... Lubricating part casing 4.
... Turbine casing 5 ... Scroll passage 6 ... Axial passage 7
...Compressor wheel 8...Main WB 9...Ring member 10.
...Bolt 11.12...Bearing hole 13...
Radial bearing metal 14... Thrust bearing metal 15... Collar 16... Bushing 17.
...Threaded portion 18...Nut 19...Hexagonal cross section 21...Scroll passage 21a...Inlet opening 21b...Outer circumference path 21c...Inflow path 2
2...Exit passage 22a...Exit opening 23...
Back plate 23a...Flange 24...To stand pole 1 25...Ring part side 26...Nut 27.
...Fixed vane member 28a...Cylindrical portion 28b...Disc portion 29...Fixed vane 30...Turbine wheel 31...Seal ring 32...Bolt 33...
Pin 34... Movable vane 35... Link mechanism 36... Shield plate 37... Center hole
38... Annular groove 40... Lubricating oil introduction hole 41...
・Lubricating oil passage 42...Lubricating oil discharge hole 43...Seal ring 44...Center hole 45...Guide plate patent applicant: Honda Motor Co., Ltd. Representative Patent attorney: Yo Oshima - No. 2 Figure 27a 1 Procedural amendment (spontaneous) May 28, 1988 Patent Application No. 125002 of 1988 2 Name of the invention Variable capacity turbine 3 Relationship with the case of the person making the amendment Patent applicant address Tokyo Minami Aoyama 2-1-1 Name (5
32) Honda Motor Co., Ltd. 4, Agent Address: 102 Iidabashi'l-, Chiyoda-ku, Tokyo
8-66, Number of inventions increasing due to amendment 0 8, ? LT+17) rlqM basket smoke z,
, , , , -,f,:L'. (Contents of the amendment) (1) The scope of claims from page 1, line 5 to page 1, line 19 of the specification is amended as follows. "It has a turbine wheel and a turbine scroll formed around the outer periphery of the turbine wheel, and a variable nozzle consisting of an arcuate vane is annularly disposed on a certain circumference outside the outer periphery of the turbine wheel. A variable @ side turbine, wherein the arcuate vane is composed of a fixed vane and a movable vane that are divided into parts, and when the movable vane tilts, the space between the fixed vane and the movable vane that face each other is The fixed vane and the movable vane form a substantially continuous airfoil cross section when the nozzle is in its narrowest state. A variable displacement turbine characterized by:

Claims (1)

[Scope of Claims] A turbine wheel comprising a turbine wheel and a turbine scroll formed around the outer periphery of the turbine wheel, and a variable nozzle consisting of an arcuate vane is provided on a certain circumference outside the outer periphery of the turbine wheel. A variable capacity turbine arranged in an annular shape, wherein the arcuate vane is composed of a fixed vane and a movable vane that are formed in segments, and the movable vane tilts inward from the circumference so that the vanes are mutually separated. The opening area of a nozzle defined between the fixed vane and the movable vane that face each other is adjusted, and the fixed vane and the movable vane are generally continuous when the nozzle is in its narrowest state. A variable capacity turbine characterized in that the turbine is configured to form an airfoil-shaped cross section.