JP2000205199A - Turbocharger - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce noise of a turbocharger without increasing space and cost. SOLUTION: In the turbocharger according to the present invention, a sound absorbing block 9 also serving as an abradable layer is disposed on the inner surface of a compressor casing 1, and the sound absorbing block 9 is extended to the upstream side of the impeller 2. Sound absorbing block 9
Is preferably formed of a foamable ceramic. According to this, the generation of the intake noise when performing suction with the impeller 2,
The radiation is suppressed, the intake noise is effectively reduced, and the noise of the turbocharger can be reduced. Since it is also used as an abradable layer, cost is prevented from increasing, and there is no increase in space because it is integrated with the compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger for a vehicle or the like, and more particularly to a structure for reducing noise during driving.

[0002]

2. Description of the Related Art A known turbocharger for a vehicle is provided with a muffler which also functions as a filter at a suction portion of a compressor in order to reduce noise during operation, thereby reducing intake noise caused by suction.

[0003]

However, in this case, since a silencer is provided separately from the turbocharger, the entire device becomes large, and the space is increased and the cost is increased.
If such a silencer is not provided, no noise measures are taken, or at best sound insulation measures are taken to prevent external leakage of sound inside the vehicle hood, and many effects cannot be expected.

[0004]

According to the present invention, there is provided a turbocharger in which a sound absorbing block serving also as an abradable layer is disposed on the inner surface of a compressor casing, and the sound absorbing block extends to the upstream side of the impeller.

The sound absorbing block is preferably made of a foamable ceramic.

[0006]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a compressor section of a turbocharger according to the present invention. Such a turbocharger is for a vehicle. As shown, the compressor casing 1
The impeller 2 is rotatably provided therein, and the impeller 2 is rotationally driven by a turbine on the left side in the drawing via a turbine shaft 3. Such a compressor is of a centrifugal type, and the intake air is sucked in the axial direction from the suction port 4 by the rotation of the impeller 2,
When passing through the impeller 2, the flow is bent at a right angle and discharged radially outward, and after passing through a diffuser 5 as an annular flow path, is sent to a scroll 6. The impeller 2 is an open impeller having a plurality of blades 8 erected on the outer peripheral surface of a hub 7.

A sound absorbing block 9 serving also as an abradable layer is provided on the inner surface of the compressor casing 1. That is,
The sound absorbing block 9 comes into contact with the rotating impeller 2 and is shaved.
The gap (shroud gap) with the impeller 2 is minimized.
Thereby, when the intake air passes through the impeller 2, the leakage of the intake air is prevented as much as possible, and the fluid performance of the compressor is improved. Here, the sound absorbing block 9 is integrally formed of a foamable (porous) ceramic.

The sound absorbing block 9 is formed in a cylindrical shape having a predetermined thickness, and is fitted to the inner peripheral portion of the compressor casing 1 and fixed with a plurality of screws 10. The compressor casing 1 can be divided in the axial direction at the position of the diffuser 5,
Of these, the axially forward (right side in the figure) inlet casing 12
The sound absorbing block 9 is fitted from behind (left side in the figure). A flange 11 is formed at the rear end of the sound absorbing block 9, which serves as a screwing portion and forms a partitioning portion of the diffuser 5. The flange 11 is fitted flush with the step 13 of the inlet casing 12. Although the head of the screw 10 is exposed in the diffuser 5, a flat head screw is used as the screw 10 and the head is buried in the flange portion 11, so that the exposed surface is substantially flat. The sound absorbing block 9 may be fixed by shrink fitting, press fitting, sintering, or the like, in addition to such screwing.

The sound absorbing block 9 extends to the upstream side of the impeller 2 and also partitions the suction port 4. That is, at least the leading edge position P of the blade 8
It extends further upstream, and covers almost the entire suction port portion of the compressor casing 1 here. The inlet-side end of the sound absorbing block 9 is tapered so that the intake of air is smoothly introduced.

According to this, since the sound absorbing block 9 is provided, generation and emission of intake sound when suction is performed by the impeller 2 are suppressed, the intake sound can be effectively reduced, and the noise of the turbocharger can be reduced. . In particular, in the related art, a high-frequency sound of about 7 kHz tends to be generated depending on the number of blades, and this is significantly suppressed by providing the sound absorbing block 9. Since the sound absorbing block 9 is provided inside the compressor casing 1, direct sound silencing is possible, and the sound absorbing effect is extremely high. Also, since it is also used as an abradable layer, the number of parts is kept to a minimum, and an increase in cost is prevented. Of course,
There is no increase in space because it is integrated with the compressor.

[0012] Conventionally, a ceramic sprayed as an abradable layer is seen, but with this, the layer thickness is thin (about 0.5 to 1 mm), and no sound deadening effect can be expected. In the present invention, a thicker sound absorbing block is provided, which is formed into a foamed structure, and is extended to the upstream side of the impeller, so that a high sound absorbing effect can be expected. In particular, the extension portion 14 on the upstream side of the impeller eliminates the resonance sound at the suction port 4, and at the same time, prevents the generation of wind noise at the suction port 4, and tries to go outside through the suction port 4 from the impeller 2. Sound can also be eliminated.

As described above, the embodiments of the present invention are not limited to those described above. For example, a turbocharger can be used for ships and the like. The sound-absorbing block can also be made of another material, or can have a divided structure.

[0014]

In summary, according to the present invention, an excellent effect that the noise of the turbocharger can be reduced without increasing the space and the cost is exhibited.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment according to the present invention.

[Explanation of symbols]

 1 compressor casing 2 impeller 9 sound absorbing block

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H034 AA02 AA17 BB03 BB06 CC03 CC04 DD05 DD22 DD24 EE06 EE12 3H035 DD03 DD05

Claims (2)

[Claims] 1. A turbocharger wherein a sound absorbing block serving also as an abradable layer is disposed on an inner surface of a compressor casing, and the sound absorbing block extends to an upstream side of an impeller. 2. The turbocharger according to claim 1, wherein said sound absorbing block is made of foamable ceramic.