1. Field of the Invention
The invention relates to a resonator for lowering airborne sound and solid-borne sound, comprising at least two annular chambers arranged between an inlet piece and an outlet piece and comprising an inner pipe, which is arranged at least between the inlet piece and the outlet piece and which has wall holes as a connection to the adjacent annular chambers.
2. Description of the Related Art
When exhaust gas turbochargers, for example, are used in conjunction with internal combustion engines, undesirable flow-generated noises result as a consequence of engine speeds, imbalances and disruptions caused by production-related warping. These flow-generated noises are lowered across a broad spectrum by appropriate resonators or dampers. In particular, the resonators or dampers are arranged between the turbocharger and the internal combustion engine or between the turbocharger and an air cooler arranged upstream of the internal combustion engine.
A resonator or tubular chamber damper is known from DE 19 55 708 B4, for example. The device disclosed therein has two adjacent annular chambers arranged between an inlet piece and an outlet piece, and an inner pipe arranged between an inlet piece and an outlet piece, said inner pipe having slit-shaped wall holes as a connection to the annular chambers surrounding the inner pipe.
In the case of the known resonator, which has essentially proved itself in practice, it is disadvantageous that when operational conditions change, i.e. the installation volume and the damping characteristics change, it must in each case be completely reconstructed, which results in particular in relatively high tool costs,.
A similar resonator is also known from DE 10 2004 049 446 A1. In this known device, the inlet piece, outlet piece, volume chamber and outlet pipe form a tubular damper unit which is formed as a single piece made of plastic. The inner pipe can be inserted into the tubular damper unit by way of the inlet piece.
The problem that the present invention seeks to solve is therefore to improve the known resonators so that they can be easily and cost-effectively adapted to different operational locations and damping conditions.
The invention relates to a resonator for lowering airborne sound and solid-borne sound. The resonator has at least first and second chambers arranged between an inlet piece and an outlet piece. An inner pipe is arranged at least between the inlet piece and the outlet piece. The inner pipe has a connection to the annular chambers. The first annular chamber has a U-shaped circumferential wall coaxial to the resonator longitudinal axis. The U-shaped circumferential wall transitions at both ends into cylindrical end pieces for accommodating the inner pipe. At least the second annular chamber has an L-shaped circumferential wall coaxial to the resonator longitudinal axis. The end of the L-shaped circumferential wall facing away from the first annular chamber transitions into a cylindrical end piece, and the end of the L-shaped circumferential wall facing the first annular chamber lies on the outer wall of the first annular chamber extending parallel to the resonator longitudinal axis.
By dispensing with the single-piece construction of the chambers and by combining the annular chambers of at least one U-shaped and one L-shaped chamber, it is possible, on the one hand, for the individual chambers to be produced more cost-effectively with lower tool costs, while on the other hand, because of their modular structure, they can be more easily and cost-effectively adapted to different installation spaces and different damping conditions. In particular, the width parallel to the resonator longitudinal axis of the first and third annular chambers with an L-shaped wall can be easily modified. Another simple and cost-effective variation of the damping characteristics can be achieved via the number and geometry of the wall holes in the inner pipe which are assigned to the annular chambers. In principle, the intended damping results from the volumes of the annular chambers and from the size of the wall holes in the inner pipe that connect the inner space of the inner pipe with the volume chambers. To achieve damping across a broad spectrum, it is advantageous to design the annular chambers with differing volumes and corresponding wall holes in the inner pipe and to coordinate these with one another. Appropriate adaptation of the wall holes to the volumes of the volume chambers results in the known action mechanisms of the Helmholtz type and/or in the manner of λ/4 resonators, which serve to lower noise for the entire arrangement.
The chosen construction of the annular chambers and of the inner pipe achieves especially high production flexibility, since the manufacturing methods are not bound to any particular tools or molds and they can be rapidly and simply adapted. Manufacturing methods not bound to any particular tools or molds include processes such as welding, lasering, cutting, pressurization of semi-finished pipes, blow molding techniques, deep drawing, etc. For instance, the first and third annular chambers can be formed as a single piece, e.g. by pressurization, then in a subsequent work step, they can be separated into the first and third annular chamber by cutting or another separation process.
According to one embodiment of the invention, a third annular chamber that has an L-shaped circumferential wall coaxial to the resonator longitudinal axis is provided, which L-shaped circumferential wall, at its end facing away from the first annular chamber, transitions into a cylindrical end piece. With its end facing towards the U-shaped chamber, the L-shaped circumferential wall of the L-shaped annular chamber lies on the outer wall of the first annular chamber, said outer wall running parallel to the resonator longitudinal axis. This represents a relatively simple way to produce a resonator with three annular chambers in which the central annular chamber coaxial to the resonator longitudinal axis has a U-shaped circumferential wall and the two outer annular chambers each have an L-shaped circumferential outer wall.
According to another embodiment of the invention, the cylindrical end piece of the circumferential wall of the respective annular chamber is designed to accommodate the inner pipe. In principle, however, the cylindrical end piece of the respective L-shaped annular chamber can also be designed to accommodate the inlet piece or the outlet piece. In this case, the inlet piece and/or the outlet piece is then designed to accommodate the inner pipe.
According to another embodiment of the invention, the wall holes are designed as slits assigned to the annular chambers. The dimensions, arrangement and number of the slits are determined according to the required damping characteristics. This makes it possible also to adapt the inner pipes to changed conditions in a relatively simple and cost-effective manner.
According to another embodiment of the invention, at least one end of the inner pipe located outside the annular chambers is designed as part of the air or gas supply system. In this connection, the end of the inner pipe arranged outside of the annular chambers can be angled, with a connection flange being provided at the free end of the inner pipe.
For predetermined installation volumes, the modular design of the resonator allows the annular chambers and the inner pipe, with its wall holes, to be matched to the required damping characteristics in a relatively simple and cost-effective manner.
The resonators can be made of plastic, steel or other acceptable materials, or combinations thereof.
Further features and advantages of the invention result from the following specific description and the drawings.
A resonator 1 for lowering airborne and solid-borne sound essentially comprises a first annular chamber 2, a second annular chamber 3 and an inner pipe 4.
The first annular chamber 2 is arranged coaxial to a resonator longitudinal axis 5 and has an essentially U-shaped circumferential wall 6 which at both ends transitions into cylindrical end pieces 7, 8. The U-shaped wall 6 has an outer wall 9 running parallel to the resonator longitudinal axis 5, said outer wall being limited by two ring-shaped side walls 10, 11 arranged perpendicular to the resonator longitudinal axis 5. The outer wall 9 transitions into the end pieces 7, 8 by way of the side walls 10, 11.
The second annular chamber 3 has an L-shaped circumferential wall 12 coaxial to the resonator longitudinal axis 5, which L-shaped circumferential wall, at its end facing away from the first annular chamber 2, transitions into a cylindrical end piece 13. At its end 14 facing the first annular chamber 2, the L-shaped wall 12 lies on the outer wall 9 of the first annular chamber 2. The L-shaped wall 12 of the second annular chamber 3 has an outer wall 15 running parallel to the resonator longitudinal axis 5 with the end 14 facing the first annular chamber. In the direction of the end piece 13 of the second annular chamber, the outer wall 15 is limited by a side wall 16 running perpendicular to the resonator longitudinal axis 5, which side wall transitions into the end piece 13 of the second annular chamber 3. The second side wall of the second annular chamber 3 is thus formed by the second side wall 11 of the first annular chamber 2.
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The inner pipe 4 has wall holes 23 as a connection to the annular chambers 2, 3, 17. The wall holes 23 are designed as slits in the exemplary embodiments of
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The embodiments discussed in the specific description and shown in the figures obviously represent merely illustrative embodiments of the present invention. In the light of the present disclosure a person skilled in the art has a broad spectrum of optional variations available. In particular, additional annular chambers or other volume chambers can be added. It is also possible to reverse the position of the inlets and outlets in order to reverse the flow direction. Finally, it is also possible to divide up the inner pipe and to form a gap instead of a slit-shaped wall hole.
Number | Date | Country | Kind |
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20 2013 103 960.8 | Sep 2013 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2014/068621 | 9/2/2014 | WO | 00 |