JPS61268804A - Variable turbine nozzle type supercharger - Google Patents

Abstract

PURPOSE:To prevent vibration of a vane, by a method wherein, in a supercharger having a variable turbine nozzle placed on the upper stream side of an exhaust turbine, the vane of the variable turbine nozzle is situated in a position radially offset from the central line of the slanted shaft of the vane. CONSTITUTION:An exhaust turbine is formed such that a turbine wheel 14 is engaged with a hollow enlarged part 13c of the end part of a rotary shaft 13 rotatably supported to the central part of a casing 1 by means of a bearing member 16. In the exhaust turbine, exhaust gas from an engine enters an annular chamber 25 through an inlet and flows to the turbine wheel 14 through a vane 26 of a vane train to rotate the turbine wheel. The vane 26 has a disc- shaped shaft part 27, and the slanted angle of the vane 26 is varied through rotation of a small shaft part 29, projected from the shaft part 27, through the medium of a ring member 31 and the like by means of a control shaft 34. In which case, the vane 26 is so positioned that it is radially offset from an inclination center C and is forced into internal contact with the outer periphery of the disc-shaped shaft part 27.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a supercharger for an internal combustion engine, called a turbocharger, which uses the exhaust gas of the internal combustion engine as a driving source, and particularly relates to a supercharger for an internal combustion engine, which uses the exhaust gas of the internal combustion engine as a driving source. The present invention relates to a supercharger of the above type having a variable turbine nozzle consisting of a row of vanes provided.

<Conventional technology> Conventionally, a type of supercharger called a turbocharger has been used for the purpose of increasing engine output.
The supercharging effect tends to be insufficient in the low speed range of the engine, which is a problem especially when supercharging engines whose operating speed ranges vary widely, such as vehicle engines. . Therefore, a row of vanes is provided on the circumference on the upstream side of the exhaust turbine, and each vane is tilted so that it can be tilted in a direction tangent to the circumferential line in the low speed range of the engine. By making the angle variable,
It is known that the flow rate of exhaust gas flowing into the exhaust turbine can be increased to improve the supercharging effect in the low speed range.

<Problems to be Solved by the Invention> However, it has been found that in such a variable turbine nozzle type supercharger, vibrations of the vanes are likely to occur during operation. The reason for this is that in order to make the inclination angle of the vane variable, the shaft connected to the proximal end of the vane can be operated through an appropriate adjustment mechanism, but such an operation mechanism This is thought to be because the direction of the moment force applied to the shaft portion changes depending on the inclination angle of the vane, whereas there is some degree of play or elastic coupling.

In other words, a vane placed in the flow of exhaust gas is subjected to an aerodynamic force as a combination of lift and drag, and generally the center of tilt of the vane does not coincide with the point of application of the aerodynamic force applied to the vane. Therefore, a moment about the tilting axis of the vane is generated. Furthermore, since the direction of such a moment differs depending on the inclination angle of the vane, undesirable vibrations may occur in conjunction with the operating mechanism for adjusting the tilting angle of the vane.

Such vibrations not only impair the durability of the supercharger, but also
This should be avoided as much as possible as it causes noise.

In view of the drawbacks of the prior art, the main object of the present invention is to provide an improved variable turbine nozzle supercharger that can effectively prevent vibration of the vanes of the variable turbine nozzle.

<Means for Solving the Problems> According to the present invention, such an object is achieved by:
A supercharger having a compressor driven by the exhaust turbine, and a variable turbine nozzle consisting of a row of vanes located upstream of the exhaust turbine and tiltably supported on a base plate, wherein the vanes are This is achieved by providing a variable turbine nozzle type supercharger characterized in that the variable turbine nozzle type supercharger is provided at a position offset in the radial direction with respect to the center line of its tilting axis. In particular, it is preferable that the vane be located inside the outer peripheral edge of the shaft portion adjacent to the base end portion of the vane.

<Function> In this way, by providing the vanes at positions offset in the radial direction with respect to their tilting axes, the aerodynamic moment force acting on the vanes is always in the same direction regardless of the vane's inclination angle. Undesirable vibrations of the vanes can be effectively avoided. Also, the vane,
If the vane is provided inside the outer circumferential edge of the shaft adjacent to the base end, the problem of creating a gap between the base end surface of the vane and the substrate can be solved.

Embodiments The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

1 and 2 show the entire supercharger according to the invention. An exhaust turbine casing 1 having an axial opening 2 is connected to a back plate 3 via an annular retaining plate 4 by means of nuts 6 screwed onto stud bolts 5 .

a compressor casing 8 having an opening 7 coaxially arranged in an opposite position to said axial opening 2;
is connected to the back plate 9 with bolts 12 via an annular retaining plate 11 similar to that described above. Exhaust turbine side back plate 3
The central part of the lubricating part casing 3a extends toward the compressor, and a back plate 9 on the compressor side is connected to the free end of the lubricating part casing 3a by bolts 10.

The casing 1.8 and the back plate 3.9 form a casing for the entire supercharger, and a rotating shaft 13 is supported in the center of the casing. The exhaust turbine side of the rotating shaft 13 forms a large diameter section 13a, and the free end thereof forms a hollow enlarged diameter section 1.
3C, and a turbine wheel 14, which may be made of ceramic, for example, is fitted from the free end of the enlarged diameter section. The large diameter portion 13a of the rotating shaft 13 is rotatably supported in a bearing hole 15 formed inside the lubricating part casing 3a by a sliding bearing member 16 which is secured by a snap ring.

The portion of the rotating shaft 13 on the compressor side forms a small diameter portion 13b, and the compressor wheel 17 fitted in the small diameter portion is prevented from being handled outward in the axial direction by a threaded portion formed at the free end of the small diameter portion. This is done by a nut 18 screwed into the. The hexagonal cross-section portion 19 formed at the farthest end of the small diameter portion 13b is for tightening the nut 18 without applying excessive torsional force to the rotating shaft 13. When fastening, the hexagonal cross section portion 19 is held with another tool to prevent the rotating shaft 13 from rotating together.

The stepped portion between the large diameter portion 13a and the small diameter portion 13b of the rotating shaft 13 comes into contact with a thrust metal 21 held between the back plate 9 on the compressor side and the lubricating part casing 3a via a thrust washer 20. , so as to be able to support the thrust force applied to the rotating shaft 13 toward the compressor side. On the other hand, the compressor side surface of the thrust metal 21 is in contact with the end surface of the bushing 23 fitted in the small diameter portion 13b. Furthermore, in order to suppress the surface pressure applied to both sides of the thrust metal 21 during installation, a thrust washer 20 is installed.
A collar 22 is interposed between the end face of the bushing 23 on the exhaust turbine side, and a nut 18 is inserted into the threaded portion of the small diameter portion 13b.
The tightening force when the
and the stepped portion between the small diameter portion 13b and the thrust washer 20
It is supported between the collar 22, the bushing 23, and the combinator wheel 17.

Exhaust gas from an engine (not shown) is introduced through an inlet opening 24 oriented tangentially to the casing 1 (see FIG. 2) and passes through an annular chamber 25 to the vane 2.
6 to the turbine wheel 14 and is discharged through the axial opening 2 into an exhaust pipe (not shown).

As best shown in FIG. 2, the vanes 26 have a different shape and are disposed on the same circumference at the outer periphery of the turbine wheel 14. These vanes 26 are provided at equal intervals in the circumferential direction, and make approximately the same angle with respect to the circumferential direction, and this inclination angle is variable. That is, the base of the vane 26 on the back plate 3 side forms a disc-shaped shaft part 27, and further comprises a small-diameter shaft part 29 that coaxially projects from the disc-shaped shaft part 27 in the direction of the back board 3. .

These small-diameter shaft portion 29 and disk-shaped shaft portion 27 are fitted into corresponding holes drilled in a substrate 28 held between the casing 1 and the back plate 3, so that the small-diameter shaft portion 29 is relatively In contrast, the disc-shaped shaft portion 27 is fitted with a gap as large as that of the corresponding hole. An annular groove 27a is formed in the outer periphery of the disc-shaped shaft portion 27, and a seal ring 36 fitted in the groove prevents exhaust gas from leaking from the hole in the substrate 28. Note that the board 28 is held between the casing 1 and the back plate 3, and is screwed onto the back plate 3 with bolts 37.

Further, as clearly shown in FIGS. 5 and 6, in the case of this embodiment, the vane 26 is offset in the radial direction with respect to its tilting center C, and the disc-shaped shaft portion 27 is It is provided so as to be inscribed in the outer peripheral edge.

The small-diameter shaft portion 29 passes through the substrate 28 toward the back plate 3, and has a disk 30 fixed to its free end. Disk 30
An enlarged head projection 30a is integrally protruded at a position on the outside in the radial direction. Supported.

The outer circumferential surface of the ring member 31 is coaxially and movably combined with the outer race 32 via a plurality of balls 33, and the outer circumferential surface of the outer race 32 has an annular shape protruding toward the back plate 3 side of the base plate 28. It is fitted into the inner peripheral surface of the protrusion 28a. Further, one end of an operating shaft 34 is fitted into a proper position of the ring member 31, and the other end of the operating shaft protrudes toward the compressor side from an arcuate slot 35 provided in a corresponding portion of the back plate 3.

Therefore, the operating shaft 3 is connected via a link mechanism (not shown).
4 in the circumferential direction, the ring member 31 rotates, and the small diameter shaft portion 29 of the vane 26 is rotated via the enlarged head projection 30a received in the notch 31a, thereby adjusting the inclination angle of the vane 26. can do.

Since the vanes 26 are exposed to the exhaust gas flow, they become quite hot during operation of the supercharger, and the disk-shaped shaft portion 27 and the substrate 2
Seizure between the disc-shaped shaft part 27 and the corresponding hole becomes a problem, but in this embodiment, a sufficient gap is secured between the disc-shaped shaft part 27 and the corresponding hole. Since the seal ring 36 is inserted into the annular groove 27a recessed on the outer periphery of the vane 27, the exhaust gas does not leak from the hole in the substrate 28, and therefore the high temperature exhaust gas does not change the angle of inclination of the vane 26. The risk of invading the adjusting mechanism and damaging its operation is also eliminated.

Further, in order to prevent exhaust gas from leaking into the lubricating oil casing 3a, the hollow enlarged diameter portion 13c of the rotating shaft 13 is
A seal ring 39 is attached to an annular groove recessed in the outer circumferential portion of the seal ring 39 to prevent leakage of exhaust gas from the gap between the enlarged diameter portion 13c and the corresponding hole. Also compressor wheel 1
Also on the side 7, a seal ring 40 similar to that described above is installed in an annular groove formed on the outer periphery of the bushing 23, and a seal ring 40 similar to that described above is attached to the rear surface of the compressor wheel 17 from the gap between the outer circumferential surface of the bushing 23 and the corresponding hole. The negative pressure generated in the lubricating part casing 3a prevents the lubricating oil from leaking to the outside of the lubricating part casing 3a.

Next, the lubrication system in this embodiment will be explained. A lubricating oil introduction hole 41 is formed in the upper end of the lubricating casing 3a in FIG. The lubricating oil is supplied to the sliding bearing member 16 and the thrust metal 21 through the lubricating oil passage. The lubricating oil discharged from each lubricating part is transferred to a cavity 42 defined in the lubricating part casing 3a.
and is collected in an oil sump (not shown).

In particular, in order to prevent the lubricating oil supplied to the thrust metal 21 from adhering to the outer circumferential surface of the bushing 23 and flowing into the compressor side, an annular groove 44 is formed on the outer circumference of the bushing 23.
is cut out, and the back plate 9 and the thrust metal 21
The bushing 23 is inserted into a hole provided in a guide plate 43 sandwiched between the bushing 23 and the guide plate 43. Further, the lower end portion of the guide plate 43 is formed in a curved shape.

Therefore, the lubricating oil flowing out from the thrust metal 21 is
The lubricating oil is prevented from flowing out toward the compressor wheel 17 along the outer circumferential surface of the bushing 23, and the lubricating oil thrown away from the outer circumferential surface of the bushing 23 by centrifugal force is caught by the guide plate 43 and sent to the oil sump. It will be returned. Therefore, the lubricating oil thrown away by the centrifugal force is scattered in the empty chamber 42 and the seal ring 39.40
It is possible to avoid a situation where the lubricating oil enters the vicinity of the lubricating oil, and it is possible to effectively prevent the lubricating oil from leaking out of the empty chamber 42.

On the other hand, the intake air taken in through the opening 7 is compressed by the compressor wheel 17, reaches the annular chamber 50, and is supplied to the intake system of the internal combustion engine from the intake outlet 51 shown in FIG.

Figures 3 and 4 illustrate the direction of aerodynamic forces in conventional vane structures.

As shown in FIG. 3, the streamline direction F of the flow of exhaust gas
When the vane 126 is inclined in the first direction,
The aerodynamic force R applied to the vane 126 is applied to the third
A moment force is generated in the clockwise direction in the figure. However, as shown in FIG. 4, when the vane 126 is inclined in the second direction with respect to the streamline direction F of the exhaust gas, the aerodynamic force R acting on the vane 126 is Generates a moment force M in the counterclockwise direction. Therefore, the direction of the moment force applied to the vane changes depending on the inclination angle of the vane, which is undesirable because it causes the vibrations described above.

Furthermore, since the outer peripheral contour of the vane 126 protrudes from the outer peripheral edge of the shaft portion 127, the proximal end surface of the vane 126 and the substrate 28
In order to perform relative movement between the base end surface of the vane 126 and the surface of the substrate 28, it is necessary to provide a certain amount of space between the proximal end surface of the vane 126 and the surface of the substrate 28 to smooth the relative movement between these two parts. . However, a problem arises in that exhaust gas leaks from this gap, reducing the efficiency of the exhaust turbine.

5 and 6 show the structure of a vane according to the present invention, in which the vane 26 is aligned with its tilting center line C, in contrast to the known type of vane structure shown in FIGS. 3 and 4. The difference is that it is located at an offset position. Therefore, as shown in FIG. 5, when the vane 26 is inclined in the first direction with respect to the streamline direction F of the exhaust gas, the aerodynamic force R acting on the vane 26 is: A moment force is generated in the clockwise direction indicated by arrow M. As shown in FIG. 6, even when the vane 26 is inclined in the second direction with respect to the streamline direction F of the exhaust gas, the aerodynamic force R acting on the vane 26 is A moment force M in the clockwise direction is generated in the same manner as above. Therefore, in the case of the vane structure according to the present invention, the direction of the moment force applied to the vane is constant regardless of the angle of inclination of the vane, so the possibility of generating undesirable vibration in the operating mechanism for tilting the vane is eliminated. be done.

Further, as shown in the above embodiment, by providing the rear end edge of the vane 26 close to the outer peripheral edge of the disc-shaped shaft portion 27, the proximal end surface of the vane 26 and the substrate 28 on the downstream side of the vane can be
It is possible to completely eliminate the clearance between the surface of the

<Effects of the Invention> As described above, according to the present invention, undesirable vibrations of the vanes can be effectively avoided simply by properly installing the vanes. This can have a great effect of improving the reliability and durability of the machine.

Further, by providing the vane in a direction closer to the turbine wheel than the center of its rotation axis, the trailing edge of the vane can be brought closer to the inlet of the exhaust turbine.

Therefore, when the vane is tilted, fluctuations in the gap between the trailing edge of the vane and the inlet of the exhaust turbine can be minimized, and the trailing edge of the vane can be brought into close contact with the disc-shaped shaft. Therefore, the secondary effect of improving the efficiency of the exhaust turbine due to any of the factors, such as improving the inflow efficiency on the downstream side of the vane, can also be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a variable turbine nozzle supercharger according to the present invention. FIG. 2 is an end view of the supercharger of FIG. 1 with a portion cut away and seen from the exhaust turbine side. FIGS. 3 and 4 are explanatory diagrams showing the direction of aerodynamic forces applied to conventional vanes. FIGS. 5 and 6 are explanatory diagrams showing aerodynamic forces applied to the vane according to the present invention. 1... Casing 2... Opening 3... Back plate 3a... Lubricating part casing 4... Holding plate 5... Stud bolt 6... Nut
7... Opening 8... Casing 9.
... Back plate 10 ... Bolt 11 ... Holding plate 1
2... Bolt 13... Rotating shaft 13a...
Large diameter part 13b... Small diameter part 13C... Hollow enlarged diameter part 14... Turbine wheel 15... Bearing hole
16... Bearing member 17... Compressor wheel 18... Nut 19... Hexagonal cross section 20.
... Thrust washer 21 ... Thrust metal 22 ... Collar 23 ...
Bushing 24... Opening 25... Annular chamber
26... Vane 27... Disc-shaped shaft portion 27a
... Annular groove 28 ... Substrate 28a ... Annular protrusion 29 ... Small diameter shaft portion 30 ... Disc 30a
... Enlarged head protrusion 31... Ring member 31a...
Notch 32...Outer race 33...Ball 34...Operation shaft 35...Slot 3
6... Seal ring 37... Bolt 39.
40... Seal ring 41... Lubricating oil inlet 42
... Vacancy 43 ... Guide member 44 ... Groove 50
...Annular chamber 51...Intake outlet 126...
Vane 127...Shaft Applicant: Honda Motor Co., Ltd. Agent: Patent Attorney: Yo Oshima - Figure 3, Figure 5, Figure 4, Figure 6

Claims (2)

[Claims] (1) A supercharger having an exhaust turbine, a compressor driven by the exhaust turbine, and a variable turbine nozzle consisting of a row of vanes located upstream of the exhaust turbine and tiltably supported on a base plate. A variable turbine nozzle supercharger characterized in that the vane is provided at a position offset in the radial direction with respect to the center line of the tilting shaft. (2) The variable turbine nozzle type supercharger according to claim 1, wherein the vane is located inside the outer peripheral edge of the shaft portion adjacent to the base end portion of the vane. .