TURBOCHARGER

The invention relates to a turbocharger as per the preamble of claim 1.

A turbocharger of said type is known from DE 10 2006 038 830 A1. Said turbocharger has a silencer in order to be able to at least lessen the occurrence of acoustic disturbances which can occur as a result of high-frequency flow noises, which may be caused for example by geometric irregularities. In unfavorable inflow situations, however, very noticeable tones can be generated by the silencer itself. A conventional silencer is composed of an air-guiding duct which is traversed by flow and to which hydraulic buffer chambers or ducts for producing buffer volumes can be coupled. The connecting points between the air-guiding duct and the buffer chambers or the ducts have a considerable thickness and sharp edges, in particular in the case of injection-molded parts. Said noticeable tones can therefore be generated by the silencer itself at the sharp edges.

It is therefore an object of the present invention to provide a turbocharger of the type specified in the preamble of claim 1, by means of which it is possible to reduce or completely eliminate tones generated by the silencer.

Said object is achieved by means of the features of claim 1.

By eliminating a sharp-edged radially inner corner, it is possible for the generation of noticeable tones by the silencer itself to be prevented without impairing the actual function of the silencer.

Subclaims 2 to 8 relate to advantageous refinements of the invention.

Claims 9 and 10 define a silencer as an object which can be marketed separately.

The radially inner corner of the edge of the opening from the air-guiding duct to the buffer chamber may be formed for example as a rounding, as a bevel or as an inwardly directed bulge.

Here, tests carried out within the context of the invention have yielded that, surprisingly, simply machining said radially inner edge makes it possible to effectively suppress the tone generation by the silencer itself.

FIG. 1 shows an embodiment of a turbocharger 1 according to the invention which has a turbine with a turbine housing 2 and has a compressor with a compressor housing 3. The compressor housing has a compressor outlet 20 to which can be attached a silencer which will be explained in detail below on the basis of the diagrammatic illustration of FIGS. 2 to 5.

All the other components of the turbocharger 1 illustrated by way of example will not be described in detail below because they are not required for explaining the principles of the present invention. For the explanation of the reference symbols used in FIG. 1, however, reference is made to the list of reference symbols.

FIG. 2 illustrates a longitudinal section through a silencer 21 according to the invention, which silencer has a silencer housing 23 provided with a first end region 22 which can be attached in a suitable manner, for example screwed, to the compressor outlet 20.

Arranged in the silencer housing 23 is an insert part 25 which has a tubular base part 37 which is provided with a spacer 38, which in the example is in the shape of a disk, for forming a buffer chamber 24. The insert part 25 may be fixed in the silencer housing 23 by means of a suitable retaining device 39 with the interposition of a sealing ring 40. The base part 37 is provided at least with one opening, but generally with two or three openings 26, which connect an air-guiding duct 27 arranged in the base part 37 to the buffer chamber 24.

The opening 26 has an edge 28 which is provided with a radially inner corner 29. The edge 28 also has a radially outer corner 29′, wherein FIG. 2 shows that the radially inner corner 29 is to be understood to mean the corner which is arranged closer to the longitudinal central line L of the silencer housing 23 than the radially outer corner 29′.

As is also shown in FIG. 2. the silencer housing 23 in the example has an integrally formed inner pipe piece 41 which, together with an outer wall 43, forms a further buffer chamber 42.

Furthermore, the silencer housing 23 is provided, on its other end region 34, with a connecting piece 33 in which, in the example, a further insert part 35 with slots is arranged, one of which slots is denoted, representatively for all of the slots, by the reference numeral 36. Said insert part 35 likewise serves as a silencer. A line to the charge-air cooler, if one is provided, or to the engine may be connected to the connecting piece 33.

To be able to prevent the generation of disturbance noises by the silencer 21 itself, the radially inner corner 29 thereof is machined in order to eliminate a sharp-edged design. FIGS. 3 to 5 show alternatives of the detail denoted in FIG. 1 by the letter A.

FIG. 3 shows a rounding 30 of the radially inner corner 29, which rounding is provided with a selectable radius R. As shown in FIG. 3, the rounding 30 in this example points outward.

FIG. 4 shows, as a detail A-2, a bevel 31 of the radially inner corner 29.

FIG. 5 shows the detail A-3, wherein in this case, an inwardly directed bulge 32 of the radially inner corner 29 is provided, which likewise has a selectable radius R.

All of said designs can prevent the occurrence of disturbance noises, since the sharp edge of the radially inner corner 29 of the edge 28 is eliminated.

In addition to the above written disclosure of the invention, reference is hereby made explicitly to the diagrammatic illustration thereof in FIGS. 1 to 5.

1 Turbocharger/exhaust-gas turbocharger

2 Turbine housing/turbine

3 Compressor housing/compressor

4 Turbine wheel

5 Adjusting ring

6 Blade bearing ring

7 Guide blades

8 Blade shaft

9 Supply duct

10 Axial connecting piece

11 Actuating device

12 Control capsule

13 Free space for guide blades 7

14 Plunger element

15 Annular part of the turbine housing 2

16 Spacer/spacer cam

17 Compressor wheel

18 Guide grate/guide apparatus

19 Bearing housing

20 Compressor outlet

21 Silencer

22 First end region

23 Silencer housing

24 Buffer chamber/buffer volume

25 Insert part

26 Opening

27 Air-guiding duct

28 Edge

29 Radially inner corner

29′ Radially outer corner

30 Rounding

31 Bevel

32 Bulge

33 Connecting piece

34 Second end region

35 Insert part

36 Slot

37 Base part

38 Spacer

39 Retaining device

40 Sealing ring

41 Pipe piece

42 Buffer chamber

43 Outer wall

L Longitudinal central line of the silencer housing 23

R Radius