Compressor Housing of a Radial Compressor

Abstract

A compressor housing (16) of a radial compressor at least two housing portions (10, 12, 14) at least partially of plastic material and defines compressor impeller installation space (48) and a spiral duct (46) that surrounds it radially on the outside with regard to a rotational axis (18) of an impeller. A securement structure (50) encloses the compressor impeller installation space (48) at least partially in an annular manner and is arranged in radial direction between the impeller installation space (48) and the spiral duct (46). The securement structure includes a separate burst-protection ring (50) with a tubular wall section (34) enclosing the impeller installation space (48) circumferentially.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC 119 to German Patent Application 102011017052.9 filed in Germany on Apr. 14, 2011, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The invention relates to a compressor housing of a radial compressor, in particular of a turbocharger of an internal combustion engine, in particular of a motor vehicle, with at least two housing components consisting at least partially of synthetic material, wherein a compressor impeller installation space and a spiral duct surrounding it radially on the outside with regard to a rotational axis of a compressor impeller are provided, and a securement structure enclosing the compressor impeller installation space at least partially in an annular manner is disposed in radial direction between the compressor impeller installation space and the spiral duct.

BACKGROUND OF THE INVENTION

A radial compressor housing in particular for a turbocharger featuring at least two housing components is known from WO 2009/065881 A1. A compressor impeller installation space and a spiral duct are provided. The housing components are made of synthetic material. The radial compressor housing can be made of synthetic material in an easy and cost-effective way. The wall thicknesses can be optimized depending on the material used and the weight. Radial compressors have to guarantee an adequate operational safety. Due to the high impeller speeds of turbochargers there is a risk that, when the compressor impeller is damaged, metal shards penetrate the housing of the compressor and damage components in the engine compartment of the internal combustion engine. To avoid this, a securement structure encloses the compressor impeller installation space partially in a ring-shaped manner. The securement structure is undetachably connected with one of the housing components. The securement structure consists of a plurality of ribs which are integrally molded to an exterior side of an external wall surrounding the compressor impeller installation space. If parts break away from the compressor impeller, stiffening measures of the ribs shall prevent the housing from being penetrated.

SUMMARY OF THE INVENTION

An objective underlying the invention is to design a compressor housing as mentioned above that can be manufactured easily and which is robust. It should be optimized with regard to the material used and the weight. Furthermore, the operational safety shall be enhanced particularly in the case when parts break away from the compressor impeller.

This is solved according to the invention by the fact that the securement structure features a separate burst-protection ring with a tubular wall section enclosing the compressor impeller installation space circumferentially and which is disposed in the compressor housing and fixed in its position.

According to the invention, a burst-protection ring is therefore provided with a tubular wall section that encloses the compressor impeller installation space circumferentially in a closed manner. Thus, the wall section forms circumferentially a preferably complete protection that prevents in particular parts breaking away from the compressor impeller from penetrating radially to the exterior. The separate burst-protection ring can be in particular optimally adapted to the shape and/or size of the compressor housing. The burst-protection ring can also be optimized for different requirements of the radial compressor with regard to its shape, size and/or material. For example, radial compressors can be designed for higher compressor impeller speeds than with known compressor housings made of synthetic material which are subjected to corresponding higher loads. As the burst-protection ring is disposed between the compressor impeller installation space and the spiral duct, it does not expand towards the exterior. In this way, the installation space needed for the compressor housing is smaller. Furthermore, the burst-protection ring cannot be seen from the outside which is optically appealing. The separate burst-protection ring can be made of the same material as the compressor housing, or it can be made of other materials. The tubular shape of the burst-protection ring stabilizes the compressor housing. It furthermore enhances the disruptive strength. A burst-protection ring which is realized separately from the housing components simplifies the manufacture of the housing components unlike the compressor housings known from prior art where the housing components must be equipped with complex shapes that form the safety structure. During installation, the burst-protection ring can simply be connected with one of the housing components before the housing is closed with the second housing component during assembly. When connecting the housing components by ultrasonic welding, the separate burst-protection ring can influence positively the developing inherent vibrations. Advantageously, the burst-protection ring dampens the inherent vibrations. As the burst-protection ring is fixed in the compressor housing in its position, this further enhances the stability of the compressor housing. Furthermore, rattling of the burst-protection ring is prevented during operation of the radial compressor. The burst-protection ring in conjunction with the circumferential wall section ensures an additional stability against a radial expansion of the wall surrounding the compressor impeller installation space. The developing heat during the operation of the radial compressor can cause a stronger expansion of the synthetic material of the compressor housing than of the material of the compressor impeller. If the compressor impeller is in particular made of metal, its thermal expansion is lower than that of the compressor housing made of synthetic material. Due to the different expansion, the radial distance between a radial outer side of the compressor impeller and a radial inner side of the wall, which defines the compressor impeller installation space, can be enlarged. This may result in a reduced efficiency of the radial compressor. The burst-protection ring can prevent the compressor housing from being radially expanded. In this way, the efficiency is less affected when the radial compressor is heated up. Advantageously, the burst-protection ring is made of a material that can absorb the kinetic energy generated by fractions possibly thrown off the compressor impeller. The compressor housing made of synthetic material in conjunction with the burst-protection ring can under severe stress pass a burst-protection test, also known as containment test, than conventional compressor housings made of synthetic material. The burst-protection ring can also be called containment ring.

In an advantageous embodiment, the burst-protection ring may be disposed in an annular space surrounding the compressor impeller installation space radially outside and which is defined by at least two of the housing components. The annular space may preferably be accessible from the outside prior to the assembly of the housing components. This makes it easy to introduce the burst-protection ring into the annular space during the assembly of the compressor housing. It can also be secured against loss at one of the housing components. When assembling both housing components, the annular space may be closed. This makes it easy to fix the burst-protection ring in the annular space. Additional fasteners are not required. The separate burst-protection ring may be disposed advantageously in an annular space which already exists in the compressor housing.

Advantageously, the burst-protection ring may be fixed in the compressor housing by means of a form-fit connection, in particular by clamping ribs and/or snap-in hooks and/or beads, and/or by means of a force-fit connection, in particular by pressing on or by pressing in the burst-protection ring, and/or by means of a cohesive connection, in particular by a glued connection, an injection connection or a welded connection. Such connections make it possible to fix the burst-protection ring easily, reliably and in a stable manner in the compressor housing. Before assembly of the housing, the burst-protection ring can be easily fixed by means of the connection at one of the housing components. Thus, it is easy to realize a loss prevention device. Both housing components can then be connected with each other. Form-fit connections can be easily realized in particular by connecting bars and grooves which can cooperate in a form-fit manner when inserting or placing the burst-protection ring on a corresponding housing part. In particular, clamping ribs and/or snap-in hooks and/or beads that already exist in the compressor housing can be used. Form-fit connections can be easily realized in a stable manner. If required, they can be loosened again easily. The advantage of force-fit connections is that they can be realized easily and in a stable manner. Additional connection components such as, in particular, ribs, snap-in hooks or beads at the burst-protection ring and at the corresponding housing component are not required. The manufacturing costs for the burst-protection ring and the housing components can be reduced accordingly. Cohesive connections allow to realize easily an additional sealing function. Cohesive connections enable in particular to seal easily gaps between the burst-protection ring and the corresponding housing component.

Furthermore, the burst-protection ring can advantageously be made at least in the wall section of a ductile material, in particular metal, synthetic material, carbon fibers, ceramics, aramid fibers or a material mix. Ductile material can feature a high impact strength, a high elongation at break and/or a high vibration damping. Ductile material can give the burst-protection ring, in particular the wall section, optimal characteristics with regard to elasticity, ductility, and deformability. In this way, the burst-protection ring can easily and reliably absorb the energy of thrown-off fractions. It can thus prevent fractions from penetrating.

In another advantageous embodiment, the burst-protection ring can at least participate in forming a wall section of the spiral duct. In this way, the burst-protection ring can participate in designing one part of the flow contour in the spiral duct. The housing components and the burst-protection ring can be assembled in a modular way to form the spiral duct. The flow contour in the spiral duct can be optimized by the shape and/or size of the burst-protection ring. Furthermore, the burst-protection ring can enhance the stability of the walls of the spiral duct.

The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying Figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.

Features of the present invention, which are believed to be novel, are set forth in the drawings and more particularly in the appended claims. The invention, together with the further objects and advantages thereof, may be best understood with reference to the following description, taken in conjunction with the accompanying drawings. The drawings show a form of the invention that is presently preferred; however, the invention is not limited to the precise arrangement shown in the drawings.

FIG. 1 is a schematic axial cross section of a compressor housing of a radial compressor according to a first example of an embodiment, wherein a burst-protection ring is disposed in an annular space which surrounds a compressor impeller installation space; and

FIG. 2 is a schematic axial cross section of a compressor housing according to a second example of an embodiment which resembles the compressor housing in FIG. 1, wherein the burst-protection ring here forms part of a wall of a spiral duct.

Identical components in the figures have the same reference numerals. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.

DETAILED DESCRIPTION

Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of apparatus components related to a compressor housing of a radial compressor. Accordingly, the apparatus components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

FIG. 1 shows a housing 16 made of three housing components, that is an upper section 10, a bottom section 12, and a middle section 14, for a radial compressor of an exhaust gas turbocharger of an internal combustion engine, The exhaust gases of the internal combustion engine drive a turbine impeller which is connected to a compressor impeller not shown in FIG. 1 for co-rotation. The compressor impeller pivots in the housing 16 around a rotational axis 18 indicated in FIG. 1. The rotation of the compressor impeller aspirates combustion air in an intake tract of the internal combustion engine and compresses it to a higher turbo pressure under which the combustion air is supplied to cylinders of the internal combustion engine

When used herein, terms such as “axial”, “radial”, “circumferentially”, and “in circumferential direction” are to be understood as relative to the rotational axis 18.

A middle section 14 is disposed between the upper section 10 and the bottom section 12. The upper section 10, the bottom section 12, and the middle section 14 are made of thermoplastics. Two annular joining areas 20 and 22 are formed at the upper section 10. A corresponding end face 24 of the middle section 14 abuts on the joining area 20. An end face 26 of the bottom section 12 abuts on the joining area 22. The joining area 20 and the end face 24 as well as the joining area 22 and the end face 26 each form weld zones.

A curvature 28 extending in an annular manner and enlarging in circumferential direction is formed at the upper section 10 in FIG. 1 and is open at the bottom. At the radially inside placed end of the curvature 28 abuts a curved section 32 on a contact area 30. The curved section 32 is adapted to the enlarged shape of the curvature 28. It is integrally molded to the middle section 14. The middle section 14 comprises furthermore an axial section 34 with a curve 36 towards a radial section 38. The curved section 32 is integrally molded to the section 38.

The bottom section 12 is designed substantially as an annular curvature 40 that enlarges in circumferential direction. A bushing 42 extending axially towards the upper section 10 is attached to the radial exterior side. The end face 26 is located at the free end of the bushing 42. An axial section 44 of the upper section 10 abuts on the internal wall of the bushing 42. The housing 16 is in this area double-walled. The bottom section 12 is—at its bottom side facing away from the upper section 10—designed to receive a housing bottom not shown in the drawing.

The curvature 28 at the upper section 10, the curved section 32 at the middle section 14, and the curvature 40 at the bottom section 12 form a spiral duct 46.

A burst-protection ring 50 which forms a compressor impeller installation space 48 is inserted in a force-fit manner to the radial outer wall of the axial section 34. The burst-protection ring 50 is made of aluminum. The housing 16 is stiffened thanks to the burst-protection ring 50. If parts break away from the compressor impeller, precautions have been taken by the burst-protection ring 50 which shall prevent the housing 16 from being penetrated.

The burst-protection ring 50 is located in a circumferential annular space 52. The annular space 52 is formed between the upper section 10 and the middle section 14. The annular space 52 encloses the axial section 34 radially outside. It is separated from the axial section 34 via the wall of the middle section 14 with respect to fluid mechanics. The burst-protection ring 50 is disposed between the compressor impeller installation space 48 and the spiral duct 46.

The burst-protection ring 50 features a tubular wall section 54 that is coaxial to the compressor impeller installation space 48. The wall section 54 encloses the compressor impeller installation space 48 circumferentially in a closed manner. The burst-protection ring 50 is fixed in its position by means of a force-fit connector assembly on the axial section 34 of the middle section 14 in the housing 16.

For manufacturing the housing 16, the upper section 10, the bottom section 12, and the middle section 14 are made of synthetic material in separate processes. The burst-protection ring 50 is made of aluminum as a separate component.

The burst-protection ring 50 is placed in a force-fit manner in axial direction on the axial section 34 of the middle section 14. In this way, it is secured against loss at the middle section 14. The middle section 14 together with the burst-protection ring 50 is inserted in axial direction into the upper section 10 so that the joining area 20 of the upper section 10 and the joining area 22 of the middle section 14 abut each other and the contact area 30 of the curved section 32 abuts against the end of the curvature 28.

The bottom section 12 is then placed in axial direction on the upper section 10 so that the end face 26 of the bottom section 12 abuts against the end face 22 of the upper section 10. The joining area 20 and the end face 24 as well as the joining area 24 and the end face 26 are then welded with each other by means of ultrasonic welding. During the welding process, the burst-protection ring 50 acts as vibration damping.

The compressor impeller is now disposed in the compressor impeller installation space 48 in a manner that is of no interest here.

FIG. 2 shows a second example of an embodiment of a housing 116. Those elements that are similar to those in the first example of an embodiment in FIG. 1 have the same reference numerals with the difference that the value 100 is added. The second example of an embodiment differs from the first example of an embodiment in that the curved section 132 that defines also the spiral duct 146, and the radial section 138 are parts of the burst-protection ring 150 instead of being integrally molded to the middle section 114, as is the case in the first example of an embodiment. The curved section 132 and the radial section 138 are integrally molded to the side of the coaxial wall section 154 of the burst-protection ring 150 that faces the bottom section 112. Thus, the burst-protection ring 150 also forms the radial wall section 138 of the spiral duct 146.

The curve 136 of the middle section 114 ends in radial direction approximately at the height of the radial outer interior side of the annular space 152. That end of the curve 136 supports the radial section 138 of the burst-protection ring 150 at its backside in radial direction that faces away from the spiral duct 146. The burst-protection ring 150 features between the coaxial wall section 154 and the radial section 138 a curve 158 that fits closely to the radial outer surface of the curve 136 of the middle section 114.

Furthermore, a plurality of ribs 156 is integrally molded to the radial outer circumferential side of the coaxial wall section 154 and the curve 158 of the burst-protection ring 150. The ribs 156 achieve a further stiffening of the burst-protection ring 150 and therefore of the housing 116.

In all the above described examples of an embodiment of a housing 16; 116 of a radial compressor of a turbocharger, the following modifications are among others possible:

The invention is not limited to housing 16; 116 of a radial compressor of a turbocharger of a motor vehicle. Rather, it can also be used with different radial compressors, for example with industrial engines.

The terms upper section 10; 110 and bottom section 12; 112 refer only to the exemplary orientation of the housing 16; 116 in FIGS. 1 and 2. The housings 16; 116 can also be oriented differently in the space, for example such that the upper section 10; 110 is located spatially at the bottom and the bottom section 12; 112 spatially at the top.

Instead of aluminum, the burst-protection rings 50; 150 can also be made of a different, preferably ductile material, in particular of a metal, synthetic material, carbon fiber, ceramics, aramid fibers or a material mix.

The burst-protection rings 50; 150 may also be fixed in the housing 16; 116 in a different way instead of pressing them on the axial section 34; 134. For example, the burst-protection rings 50; 150 may be fixed in the housing 16; 116 by means of another force-fit connection, a form-fit connection, for example by means of clamping ribs and/or snap-in hooks and/or beads and/or by means of a cohesive connection, for example by means of a glued connection, an injection connection or a welded connection.

In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.

Claims

1. A compressor housing (16; 116) of a radial compressor or turbocharger comprising:

at least two housing components (10, 12, 14; 110, 112, 114) comprising a molded synthetic material;

a compressor impeller installation space (48; 148) defined by said housing components and arranged in said housing;

a spiral duct (46; 146) defined by said housing and arranged within said housing radially spaced outwardly from and circumferentially surrounding said compressor impeller installation space (48; 148) relative to a rotational axis (18; 118) of a compressor impeller;

a securement structure (50; 150, 156) circumferentially surrounding and enclosing said compressor impeller installation space (48; 148) at least partially in an annular manner,

wherein said securement structure (50; 150, 156) is arranged in radial direction between said compressor impeller installation space (48; 148) said the spiral duct (46; 146);

wherein said securement structure includes a separate burst-protection ring (50; 150) having a tubular wall section (34; 134) enclosing said compressor impeller installation space (48; 148) circumferentially and enclosed completely within said compressor housing (16; 116), said burst-protection ring (50; 150) with tubular wall section (34; 134) secured in a fixed position within said housing.

2. The compressor housing according to claim 1, wherein

said burst-protection ring (50; 150) is arranged within and enclosed within an annular space (52; 152) defined within said housing, said annular space surrounding said compressor impeller installation space (48; 148) radially outside,

wherein said annular space is defined by and enclosed by at least two of said housing components (10, 14; 110, 114).

3. The compressor housing according to claim 1, wherein

said burst-protection ring (50; 150) is securely fixed in position within said compressor housing (16; 116) by a form-fit connection,

wherein said form-fit connection is any of: by clamping ribs and/or snap-in hooks and/or beads, and/or by means of a force-fit connection,

wherein said forcer fit connection is any of: by pressing on or by pressing in the burst-protection ring, and/or cohesive connection,

wherein said cohesive connection is any of: a glued connection, an injection connection or a welded connection.

4. The compressor housing according to claim 1, wherein

said tubular wall section (34;134) of said burst-protection ring (50; 150) is made of a ductile material selected from the set consisting of: metal, synthetic material, carbon fibers, ceramics, aramid fibers or a material mix.

5. The compressor housing according to claim 1, wherein

said burst-protection ring (150) forms a portion of a wall section defining said spiral duct (146).

6. The compressor housing according to claim 2, wherein

said burst-protection ring (50; 150) is securely fixed in position within said compressor housing (16; 116) by a form-fit connection,

wherein said form-fit connection is any of: by clamping ribs and/or snap-in hooks and/or beads, and/or by means of a force-fit connection,

wherein said forcer fit connection is any of: by pressing on or by pressing in the burst-protection ring, and/or cohesive connection,

wherein said cohesive connection is any of: a glued connection, an injection connection or a welded connection,

wherein said tubular wall section (34;134) of said burst-protection ring (50; 150) is made of a ductile material selected from the set consisting of: metal, synthetic material, carbon fibers, ceramics, aramid fibers or a material mix, and

wherein said burst-protection ring (150) forms a portion of a wall section defining said spiral duct (146).