JPH0330590Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention uses exhaust gas from an internal combustion engine as a driving source.
The present invention relates to a so-called turbocharger for an internal combustion engine, and more particularly to the above type of supercharger having a variable turbine nozzle consisting of a row of vanes provided at the inlet portion of an exhaust turbine.

<Conventional technology> Conventionally, a type of supercharger called a turbocharger has been used for the purpose of increasing engine output, but the supercharging effect tends to be insufficient in the low speed range of the engine. However, this has been a problem especially when supercharging an engine whose operating speed range varies widely, such as a vehicle engine. Therefore, a blade row consisting of vanes is provided on a certain circumference on the upstream side of the exhaust turbine, and each vane is tilted in a direction tangent to the circumferential line in the low speed range of the engine. It is known that by making the inclination angle variable, the flow velocity of exhaust gas flowing into the exhaust turbine can be increased and the supercharging effect in a low speed range can be improved.

<Problems to be solved by the invention> In such a supercharger, a substrate defining a part of the exhaust gas passage is used to pivotally support the vanes, and a bearing for the vanes is used. A relatively thick member is used as the substrate due to the necessity of providing it and to avoid deformation due to heat. As a result, the heat mass of the board becomes large, and the heat of the exhaust gas is transferred to the tilting mechanism of the vane, adversely affecting the bearings of the tilting mechanism, or the heat is transferred to the rotating shaft of the turbine and its lubrication system, resulting in poor lubrication. , deterioration of lubricating oil, deposition of carbon, etc. are disadvantageous.

In view of these drawbacks of the prior art, the main object of the present invention is to provide a supercharger of the above type that has a structure capable of suppressing heat transfer from the exhaust turbine region to the vane tilting mechanism or the lubrication structure. It is in.

<Means for Solving the Problems> According to the present invention, the present invention has an exhaust turbine, a compressor driven by the exhaust turbine, and a compressor located upstream of the exhaust turbine that is tiltable on a base plate. In a supercharger having a variable turbine nozzle consisting of a row of pivotally supported vanes, a heat shield is provided between the outer periphery of the base plate and the scroll casing, facing the inner surface of the scroll casing and the back surface of the exhaust turbine. A plate is sandwiched between the substrate and the heat shield plate, and the substrate and the heat shield plate are integrally connected via a bearing bushing that pivotally supports the vane, and a central portion of the casing having a bearing portion of the exhaust turbine and the substrate. This is achieved by providing a variable turbine nozzle supercharger characterized in that a gap is formed on the surface facing the heat shield plate.

<Function> In this way, for example, a heat shield plate made of a material with a relatively small heat mass is provided facing the inner part of the scroll casing and the back side of the exhaust turbine,
In addition, if a gap is formed in the center of the casing and in the opposing surface between the substrate and the heat shield plate, heat transfer from the exhaust turbine side can be suitably suppressed. Moreover, by fixing the heat shield plate to a highly rigid base plate through the bearing bush of the vane shaft, the heat shield plate and the casing can be rigidly bonded by simply having only the outer circumference of the heat shield plate in direct contact with the casing. It is possible to ensure a good bond.

<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 present invention. An exhaust turbine casing 1 with an axial opening 2 is connected to a back plate 3 by a nut 6 screwed onto a stud bolt 5 .
A compressor casing 8 having an opening 7 coaxially provided at a position opposite to the axial opening 2 is connected to a back plate 9 via an annular holding plate 11 with bolts 12. The central part of the back plate 3 on the exhaust turbine side forms a lubricating part casing 3a extending toward the compressor side.
The back plate 9 on the compressor side is the lubricating part casing 3a
It is connected to the free end of the bolt 10 by a bolt 10.

These casings 1, 8 and back plates 3, 9 form a casing for the entire supercharger, and a rotating shaft 13 is supported at the center of the casing. The exhaust turbine side of the rotating shaft 13 forms a large diameter portion 13a,
Its free end consists of a hollow enlarged diameter section 13c into which a turbine wheel 14, which may be made of ceramic, for example, is fitted. The large diameter portion 13a of the rotating shaft 13 is rotatably supported by a sliding bearing member 16 which is secured by a snap spring in a bearing hole 15 formed inside the lubricating part casing 3a.

The part of the rotating shaft 13 on the compressor side is the small diameter part 1.
3b, and the compressor wheel 17 fitted in the small diameter portion is prevented from coming off in the axial direction outward by a nut 18 screwed into a threaded portion formed at the free end of the small diameter portion. . Small diameter part 1
A hexagonal cross-section portion 19 formed at the farthest end of 3b
This is to enable the nut 18 to be fastened without applying excessive torsional force to the rotating shaft 13, and when fastening the nut 18, the hexagonal cross section portion 19 is gripped with another tool. In this way, it functions to prevent the rotation 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 contacts the thrust metal 21 held between the back plate 9 on the compressor side and the lubricating part casing 3a via the thrust washer 20, It is designed to support the thrust force applied to the rotating shaft 13 toward the compressor. 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 into the small diameter portion 13b. Furthermore, in order to suppress the surface pressure applied to both surfaces of the thrust metal 21 during installation, a collar 22 is interposed between the thrust washer 20 and the end surface of the bushing 23 on the exhaust turbine side.
The tightening force when the nut 18 is fastened to the threaded portion of the rotating shaft 13 is the same as that of the large diameter portion 13a and the small diameter portion 13b of the rotating shaft 13.
The thrust washer 20, the collar 22, the bushing 23, and the compressor wheel 17 support the compressor 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), passes through an annular chamber 25 and through vanes 26 to the turbine wheel 14. The gas is then discharged from the axial opening 2 to an exhaust pipe (not shown).

As clearly shown in FIG. 2, the vanes 26 have an airfoil shape and are arranged on the same circumference around the outer circumference of the turbine wheel 14. These vanes 26 are provided at equal intervals in the circumferential direction and form 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 is composed of a disc-shaped shaft part 27 and a small-diameter shaft part 29 coaxially protruding from the disc-shaped shaft part 27 in the direction of the back board 3. These small diameter shaft portion 29 and disc-shaped shaft portion 27 are
It is rotatably fitted into a bearing bush 36 which is fitted through a heat shielding plate 37 which is overlapped with each other and held between the casing 1 and the back plate 3 and a substrate 28 made of a relatively rigid material. has been done.

The heat shield plate 37 may be formed by press molding or forging, for example, from a stainless steel material, and has an annular shape as a whole and is superimposed on the surface of the substrate 28 on the exhaust turbine side. The surface of the heat shield plate 37 on the turbine wheel 14 side is flat to define the exhaust gas passage, but the surface on the substrate 28 side is recessed so that only the outer peripheral edge 37a can come into contact with the substrate 28. It is like that. Furthermore, this heat shielding plate 3
The inner circumferential edge 37b of the exhaust turbine 14 reaches the back of the blade of the exhaust turbine 14. On the other hand, the inner peripheral end surface 28b of the substrate 28 is connected to the turbine wheel 14 of the back plate 3.
It is fitted into the outer circumferential surface of the protrusion protruding from the side surface with relatively little gap.

The end of the bearing bush 36 on the vane 26 side is stepped to correspond to a counterbore formed in the heat shield plate 37. On the other hand, the back plate 3 is inserted through the substrate 28.
The sidewardly projecting end is welded to the substrate around its periphery. In this way, the substrate 28 and the heat shield plate 3
7 are integrated via a bearing bush 36.

The small diameter shaft portion 29 of the vane shaft is connected to the bearing bush 36.
to the back plate 3 side with relatively no gaps,
A disk 30 is fixed to its free end. An enlarged head projection 30a is integrally provided at a position on the outside in the radial direction of the disc 30, and a recessed projection 30a is provided on the surface of the ring member 31 surrounding the annular row of these discs 30 on the turbine wheel 14 side. It is supported by the notch 31a.

The inner peripheral surface of this ring member 31 has a plurality of balls 3
3 so as to coaxially roll with the inner race 32, and the inner circumferential surface of the inner race 32 is fitted into the outer circumferential surface of an annular step formed in a part of the back plate 3. 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 is inserted into an arcuate slot 35 provided in a corresponding portion of the back plate 3.
It protrudes from the compressor towards the compressor side.

Therefore, if the operating shaft 34 is driven in the circumferential direction via a link mechanism (not shown), the ring member 3
1 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.

Furthermore, in order to prevent exhaust gas from leaking into the lubricating oil casing 3a, a seal ring 39 is attached to an annular groove recessed in the outer circumference of the hollow expanded diameter portion 13c of the rotating shaft 13. This prevents exhaust gas from leaking from the gap between the portion 13c and the corresponding hole.

On the other hand, the intake air sucked in through the opening 7 is compressed by the compressor wheel 17 and placed in the return chamber 50.
Then, it is supplied to the intake system of the internal combustion engine from the intake outlet 51 shown in FIG. Further, on the side of the compressor wheel 17, a seal ring 40 similar to that described above is installed in an annular groove formed in the outer circumference of the bushing 23, and compressor is removed from the gap between the outer circumferential surface of the bushing 23 and the corresponding hole. The negative pressure generated on the back surface of the bushing wheel 17 prevents lubricating oil from leaking to the outside of the lubricating part casing 3a.

During operation of the supercharger, the vicinity of the annular chamber 25 and the vane 26 through which exhaust gas flows becomes quite high temperature, and the heat of the exhaust gas is transferred to the structure for tilting the vane 26 or to the lubrication system described later. The problem is that it may have an adverse effect. However, in this embodiment, since the heat shielding plate 37 having a relatively small heat mass is used, the heat transfer to the portions that are easily affected by heat is suitably suppressed. In particular, only the outer peripheral edge 37a abuts on the board 28, and the heat shield plate 37 and the board 28 are only partially connected by the bearing bush 36. Moreover, a hollow part 38 is formed in the gap between the substrate 28 and the heat shield plate 37, and the center part of the heat shield plate is not in contact with the end surface of the lubricating oil casing 3a on the turbine wheel 14 side, so that heat can be transferred. The effect of suppressing this can be further enhanced.

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 sliding bearing member 16 and the thrust metal 21 pass through the lubricating oil passage.
is supplied to. 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 peripheral surface of the bushing 23 and flowing into the compressor side, the bushing 2
An annular groove 44 is cut on the outer periphery of 3, and
A bushing 23 is inserted into a hole provided in a guide plate 43 interposed between the back plate 9 and the thrust metal 21. 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 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 prevented from flowing out toward the compressor wheel 17 side. The oil is received by the guide plate 43 and returned to the oil sump. Therefore, the lubricating oil thrown away by the centrifugal force is scattered in the empty chamber 42 and the seal rings 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.

<Effects of the invention> As described above, according to the invention, with an extremely simple structure, it is possible to effectively prevent the heat of exhaust gas from being transmitted to parts that are easily affected by heat, and it is possible to Since problems regarding adhesion and thermal deformation do not occur, the reliability of the supercharger is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a variable turbine nozzle type supercharger based on 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. 1... Casing, 2... Opening, 3... Back plate, 3a... Lubricating part casing, 5... Stud bolt, 6... Nut, 7... Opening, 8... Casing, 9... Back Plate, 10... Bolt, 11...
... Holding plate, 12 ... Bolt, 13 ... Rotating shaft, 1
3a...large diameter part, 13b...small diameter part, 13c...
Hollow expanded diameter portion, 14... Turbine wheel, 15...
... Bearing hole, 16 ... Bearing member, 17 ... Compressor wheel, 18 ... Nut, 19 ... Hexagonal section, 20 ... Thrust washer, 21 ... Thrust metal, 22 ... Collar, 23 ... Bushing, 24...opening, 25...annular chamber, 26...
Vane, 27...Disc-shaped shaft portion, 28...Substrate, 2
8a...Outer peripheral edge, 28b...Inner peripheral end surface, 29...
Small diameter shaft portion, 30... disc, 30a... enlarged head protrusion,
31...Ring member, 31a...Notch, 32...
...Inner race, 33...Ball, 34...Operation shaft, 35...Slot, 36...Bearing bush,
37... Heat shielding plate, 37a... Outer periphery, 37b...
... Inner peripheral part, 38 ... Hollow part, 39, 40 ... Seal ring, 41 ... Lubricating oil inlet, 42 ... Vacant chamber, 43 ... Guide plate, 44 ... Annular groove, 50 ...
...Annular chamber, 51...Intake outlet.

Claims (1)

[Claims for Utility Model Registration] 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 pivotably supported on a base plate. In the turbocharger, a heat shielding plate facing the inner surface of the scroll casing and the back surface of the exhaust turbine is sandwiched between the outer peripheral part of the substrate and the scroll casing, and the heat shielding plate and the heat shielding plate are are integrally connected via a bearing bushing that pivotally supports the vane, and a gap is formed in a central portion of a casing having a bearing portion of the exhaust turbine and a surface facing the substrate and the heat shield plate. A variable turbine nozzle type supercharger characterized by: