FR3053756A1 - THERMAL PROTECTION DEVICE FOR THERMAL MOTOR TURBOCHARGER - Google Patents

Abstract

The invention relates mainly to a turbocharger assembly (11) comprising: - a compressor block (12), - a turbine block (13), - a central bearing (15) interposed between said compressor block (12) and said turbine block (13), said central bearing (15) surrounding a connecting shaft between said compressor block (12) and said turbine block (13), and - a thermal protection device (16), characterized in that said thermal protection device (16) comprises a blade (17) positioned axially between said turbine block (13) and said central bearing (15), said blade (17) being an insert fixed on said central bearing (15).

Description

Holder (s): PEUGEOT CITROEN AUTOMOBILES SA Société anonyme.

Extension request (s)

Agent (s): PEUGEOT CITROEN AUTOMOBILES SA Public limited company.

THERMAL PROTECTION DEVICE FOR A TURBOCHARGER OF A THERMAL ENGINE.

FR 3 053 756 - A1 (£ /) The invention relates mainly to an assembly for a turbocharger (11) comprising:

- a compressor block (12),

- a turbine block (13),

a central bearing (15) interposed between said compressor block (12) and said turbine block (13), said central bearing (15) surrounding a connecting shaft between said compressor block (12) and said turbine block (13), and

- a thermal protection device (16), characterized in that said thermal protection device (16) comprises a blade (17) positioned axially between said turbine block (13) and said central bearing (15), said blade (17) being an attached part fixed to said central bearing (15).

THERMAL PROTECTION DEVICE FOR A TURBOCHARGER OF A THERMAL ENGINE The present invention relates to a thermal protection device for a turbocharger of a heat engine. The invention finds a particularly advantageous, but not exclusive, application in the field of motor vehicles.

There are known powertrains comprising a supercharged engine by means of a turbocharger comprising a compressor block, a turbine block and a central bearing interposed between the compressor block and the turbine block. This central bearing surrounds the connecting shaft between the turbine and the compressor.

The compressor unit includes a compressor and a low pressure air inlet in fluid communication with an air filter adapted to purify the intake air. The compressor block also includes a high pressure supply air outlet. The compressed air at the outlet of the compressor block is then directed to an air / air heat exchanger to be cooled before admission to the engine.

Furthermore, the turbine block comprises an inlet and an outlet for the exhaust gases produced by the engine and collected by means of an exhaust manifold. At the outlet of the turbine block, the exhaust gases are directed through a catalyst and a particle filter to be decontaminated.

The temperature in the vicinity of the turbine block being high, it is known to isolate the walls of the turbine block from the surrounding environment using a heat shield. As shown in FIG. 1, the applicant has developed a heat screen 1 provided with a blade 2 separating the turbine block 3 relative to the central bearing 4.

However, between the turbocharger 5 and the heat shield 1, hot air is leaked towards supply lines 6 for water and / or oil. The maximum temperature criteria around 200 ° C are therefore likely to be exceeded, which creates a risk of coking of the oil. The leaks are due to the need to provide a functional clearance of proximity between the heat shield 1 and the connection zone 7 between the central bearing 4 and the turbine block 3.

The invention aims to effectively remedy these drawbacks by proposing an assembly for a turbocharger comprising:

- a compressor block,

- a turbine block,

a central bearing interposed between the compressor block and the turbine block, the central bearing surrounding a connecting shaft between the compressor block and the turbine block, and

- A thermal protection device, characterized in that the thermal protection device comprises a blade positioned axially between the turbine block and the central bearing, the blade being an attached part fixed to the central bearing.

It is specified that the blade is constituted by a preferably metallic plate, of small thickness. The plate can be flat or bent. It can thus be provided with a rim on the side of its upper end so as to have a bent shape. In all cases, the blade has a transverse flat part extending between the turbine block and the central bearing to provide a thermal barrier function between these two elements.

The invention thus allows, by reducing the functional clearance between the blade and the central bearing, to reduce hot air leaks to the central bearing and therefore to reduce the risk of coking of the oil. In addition, the invention also makes it possible to improve the vibratory behavior of the thermal protection device by creating a fixing element on the central bearing.

According to one embodiment, the central bearing comprises at least one fixing lug to ensure attachment of the blade on the central bearing.

In one embodiment, the thermal protection device further comprises a heat shield fixed on the blade. Such a configuration makes it possible to reduce the functional clearances on either side of the blade.

In one embodiment, the heat shield is fixed on a flange extending at the outer periphery of the blade.

In one embodiment, the assembly comprises a supply line for lubrication liquid and / or a coolant line opening into the central bearing.

According to one embodiment, a fixing of the blade is combined with the fixing of one of the pipes.

According to one embodiment, the blade is interposed axially between the lubrication liquid supply line and a fixing zone between the central bearing and the turbine block.

In one embodiment, the blade and the heat shield are made of a metallic material.

The invention also relates to a heat engine, in particular for a motor vehicle, comprising an assembly for a turbocharger as defined above.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

Figure 1, already described, is a perspective view in section of a thermal protection device for a turbocharger;

Figure 2 is a perspective view in section of an improved thermal protection device for a turbocharger according to the present invention.

Identical, similar, or analogous elements retain the same reference from one figure to another.

Figure 2 shows a turbocharger 11 of a heat engine comprising a compressor block 12 and a turbine block 13. A central bearing 15 is interposed between the compressor block 12 and the turbine block 13. This central bearing 15 surrounds a connecting shaft between the compressor block 12 and the turbine block 13.

The compressor block 12 includes a compressor and a low pressure air inlet in fluid communication with an air filter adapted to purify the intake air. The compressor block 12 also includes a high pressure supply air outlet. The compressed air at the outlet of the compressor block 12 is then directed to an air / air heat exchanger to be cooled before admission to the engine.

Furthermore, the turbine unit 13 includes an inlet and an outlet for the exhaust gases produced by the engine and collected by means of an exhaust manifold. At the outlet of the turbine block 13, the exhaust gases are directed through a catalyst and a particle filter to be decontaminated.

The turbocharger 11 is equipped with a thermal protection device 16 provided with a blade 17 made of a thermally conductive material, for example metal. This blade 17 is positioned axially between the turbine block 13 and the central bearing

15. The blade 17 is an attached part fixed to the central bearing 15 into which opens a line 20 for supplying lubrication liquid, in particular oil. The central bearing 15 may also include a coolant line.

In this case, the blade 17 is interposed axially between the oil line 20 and a fixing zone 22 between the central bearing 15 and the turbine block 13. This fixing zone 22 may be constituted by radial beads. 25 formed in the central bearing 15 and the turbine block 13 and enclosed by a clamp 27.

The blade 17 is preferably positioned on one side of the fixing zone 22 in a groove 29 of the central bearing 15 receiving one end of the clamping collar 27 so as to create a baffle for the hot air and thus limit the heating of the central bearing 15. The fixing of the blade 17 can be combined with the fixing of one of the pipes.

The blade 17 is for example constituted by a thin metal plate. The plate may be flat or provided with a flange 40 on the side of its upper end so as to have a bent shape, as in the example shown in FIG. 2. In all cases, the blade 17 has a flat transverse part s extending between the turbine block 13 and the central bearing 15 to provide a thermal barrier function between these two elements. By transverse orientation is meant an orientation substantially perpendicular to an axis X of the turbocharger

11. The blade 17 is also open in its lower part to allow it to be mounted around the central bearing 15. The blade 17 may thus for example have an overall semi-circular shape.

The blade 17 is fixed on the central bearing 15 by means of a lug 33 for fixing the central bearing 15. This lug 33 has a first portion fixed, for example by riveting or welding, on a pad 36 of the central bearing 15, and a second bent portion to which the blade 17 is fixed.

The attachment of the tab 33 to the blade 17 can be achieved by punching by form cooperation between these two elements and / or by riveting. Other types of attachment are of course conceivable. The type of fixing chosen depends on the application.

Advantageously, the blade 17 is provided at its outer periphery with a flange 40 extending axially relative to the axis X of the turbocharger 11. In this case, the flange 40 is directed axially towards the compressor block 12 .

A heat shield 42 made of a thermally conductive material, for example metal, is fixed on this flange 40 so as to cover the assembly formed by the central bearing 15 and the turbine block 13. The heat shield 42 s 'extends substantially in an axial direction relative to the X axis.

For this purpose, the flange 40 may be provided with nuts, for example riveted in the flange 40, intended to receive fixing screws for fixing the heat shield 42 on the blade 17. Such a configuration makes it possible to reduce the functional clearances on either side of the blade 17. Other fixing means are of course conceivable.

In all cases, there is preferably provided a removable link to gain access to the elements of the turbocharger 11 in the context of maintenance operations. As a variant, the heat shield 42 could however be in one piece with the blade 17.

The invention thus allows, by reducing the functional clearance between the blade and the central bearing, to reduce hot air leaks to the central bearing 15 and therefore to reduce the risk of coking of the oil. In addition, the invention also makes it possible to improve the vibratory resistance of the thermal protection device 16 by creating a fixing element on the central bearing 15.

Claims (9)

1. Turbocharger assembly (11) comprising: - a compressor block (12), - a turbine block (13), a central bearing (15) interposed between said compressor block (12) and said turbine block (13), said central bearing (15) surrounding a connecting shaft between said compressor block (12) and said turbine block (13), and - a thermal protection device (16), characterized in that said thermal protection device (16) comprises a blade (17) positioned axially between said turbine block (13) and said central bearing (15), said blade (17) being an attached part fixed to said central bearing (15). 2. Assembly according to claim 1, characterized in that said central bearing (15) comprises at least one lug (33) for fixing to secure said blade (17) on said central bearing (15). 3. Assembly according to claim 1 or 2, characterized in that said thermal protection device (16) further comprises a thermal screen (42) fixed on said blade (17). 4. The assembly of claim 3, characterized in that said heat shield (42) is fixed on a flange (40) extending at the outer periphery of said blade (17). 5. An assembly according to any one of claims 1 to 4, characterized in that it comprises a pipe (20) for supplying lubrication liquid and / or a coolant pipe opening into said central bearing (15) . 6. An assembly according to claim 5, characterized in that a fixing of said blade (17) is combined with the fixing of one of said pipes. 7. An assembly according to claim 5 or 6, characterized in that said blade (17) is interposed axially between said line (20) for supplying lubrication liquid and a fixing zone (22) between said central bearing (15) and said turbine block (13). 8. An assembly according to claim 3, characterized in that said blade (17) and said heat shield (42) are made of a metallic material. 9. Heat engine, in particular for a motor vehicle, characterized in that it comprises an assembly for a turbocharger (11) as defined in one 5 any of the preceding claims. 1/1