COVER

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and all the benefits of U.S. Provisional Application No. 61/934,057, filed on January 31, 2014, and entitled "Method of Retaining A Noise

Attenuation Device In A Compressor Cover," which is incorporated herein by reference.

BACKGROUND

Field of the Disclosure

This disclosure relates to a method of retaining a noise attenuation device in a compressor cover air inlet of a turbocharger. More particularly, this disclosure relates to a compressor housing, a method, and a device regarding using a staking tool that deforms compressor cover material to retain the noise attenuation device.

Description of Related Art

Advantages of turbocharging include increased power output, lower fuel consumption and reduced pollutant emissions. The turbocharging of engines is no longer primarily seen from a high-power performance perspective, but is rather viewed as a means of reducing fuel consumption and environmental pollution on account of lower carbon dioxide (CO2) emissions. Currently, a primary reason for turbocharging is using exhaust gas energy to reduce fuel consumption and emissions. In turbocharged engines, combustion air is pre- compressed before being supplied to the engine. The engine aspirates the same volume of air- fuel mixture as a naturally aspirated engine, but due to the higher pressure, thus higher density, more air and fuel mass is supplied into a combustion chamber in a controlled manner. Consequently, more fuel can be burned, so that the engine's power output increases relative to the speed and swept volume. In exhaust gas turbocharging, some of the exhaust gas energy, which would normally be wasted, is used to drive a turbine. The turbine includes a turbine wheel that is mounted on a rotatable shaft and is rotatably driven by exhaust gas flow. The turbocharger returns some of this normally wasted exhaust gas energy back into the engine, contributing to the engine's efficiency and saving fuel. A compressor, which is driven by the turbine, draws in filtered ambient air, compresses it, and then supplies it to the engine. The compressor includes a compressor impeller that is mounted on the same rotatable shaft so that rotation of the turbine wheel causes rotation of the compressor impeller.

Turbochargers typically include a turbine housing connected to the engine's exhaust manifold, a compressor housing connected to the engine's intake manifold, and a bearing housing coupling the turbine and compressor housings together.

This disclosure focuses on the compressor end of a turbocharger. The compressor is designed to help increase the pressure and density of air in the engine air intake manifold to allow the engine cylinders to ingest a greater mass of air during each intake stroke. The compressor includes a tubular air inlet that allows airflow to the compressor wheel. Usually, the inner wall of the inlet is tapered, which may be molded as an integral inner wall or provided as a wall of an insert in the inlet.

An annular baffle is one type of insert. UK Patent 2,256,460 shows an example with a portion of the inlet defined by an annular baffle mounted on the compressor housing. The frustoconical baffle may be mounted by fixing screws or bolts, by press fitting into the housing or by snap fitting engagement. Noise can be reduced due to changes in the direction of the path of the airstream. This baffle attenuates noise.

SUMMARY

This disclosure relates to a method of retaining a noise attenuation device in a compressor cover air inlet diameter of a turbocharger. A method and a device include using a staking tool that deforms compressor cover material, such as metal, to retain a noise attenuation device.

The staking tool and an impact pedestal (press) can deform the compressor cover material (i.e. metal) around the noise attenuation device and secure the noise attenuation device in place. The staking tool includes indenters extending from an end.

A compressor housing with a secured noise attenuation device may have a first shoulder in an air inlet section of a compressor cover with the noise attenuation device seated on the first shoulder and a second shoulder in the compressor cover of a larger diameter than the first shoulder that is deformed to secure the noise attenuation device in the compressor cover.

A method of retaining a noise attenuation device in a compressor cover having a first shoulder and second shoulder at an air inlet section may include the steps of mounting the compressor cover, with the air inlet section preferably facing upwardly; placing or dropping the noise attenuation device into the air inlet section against the first shoulder; applying an impact load with a staking tool; and deforming compressor cover material of the second shoulder around the noise attenuation device with impact of indenters of the staking tool securing the noise attenuation device in place in the compressor cover.

This method of retaining a noise attenuation device to a compressor cover negates the use of additional operations, such as machining screw threads, drilling and pinning, and applying adhesive, which are all current methods of retaining noise attenuation devices.

Advantages of retaining a noise attenuation device with a staking tool to deform compressor cover material include simplicity of design, less machining, speed of assembly, fewer parts, and no cure time for adhesives. Parts cannot work loose, and there are fewer parts that can vibrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present disclosure will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Figure 1 is a perspective view of a noise attenuation device secured in a compressor cover of a compressor housing of a turbocharger;

Figure 2 is a perspective view of a noise attenuation device;

Figure 3 is a cross section of the perspective view of the noise attenuation device of Figure 2;

Figure 4 shows cross-sectional view of a compressor cover with two shoulders;

Figure 5 shows an expanded side view of a staking tool moving toward a noise attenuation device to be seated in a compressor cover on a compressor housing;

Figure 6 is a cross-sectional view of a portion of a noise attenuation device moving toward a compressor cover of a compressor housing;

Figure 7 is a cross-sectional view of a mounting face of a noise attenuation device seated on a shoulder of compressor cover; Figure 8 is a perspective view of a staking tool with an indenter moving toward a noise attenuation device seated on a shoulder;

Figure 9 shows a cross-sectional view of an indenter of a staking tool being pressed into a shoulder adjacent to a noise attenuation device; Figure 10 is a cross-sectional view of the deformation of the compressor cover securing the noise attenuation device;

Figure 11 shows a perspective view of staking tool with indenters; and

Figure 12 shows a perspective view of an indenter on the staking tool.

DETAILED DESCRIPTION OF THE EMBODIMENTS A turbocharger is generally known and includes a turbine and a compressor, wherein a compressor impeller is rotatably driven via a rotatable shaft by a turbine wheel. The rotatable shaft is supported in a bearing housing between a turbine housing connected to an engine's exhaust manifold and a compressor housing 12 connected to the engine's intake manifold.

The term compressor housing 12, as generally understood and used herein, broadly means the component that houses the compressor impeller and includes the compressor cover 14 with an air inlet section 16. Figure 1 shows a noise attenuation device 20 secured in a compressor cover 14 of a compressor housing 12. Figure 4 shows a compressor cover 14 with a hollow, cylindrical air inlet section 16 at the outermost portion of the cover 14 where air flows in. As shown in Figures 4 and 6 through 10, the air inlet section 16 has an outer wall 22 with a first shoulder 24 and a second shoulder 26 formed on an inner surface of the outer wall 22.

The compressor housing 12 has a compressor cover 14 with the first shoulder 24 as an inner diameter of the air inlet section 16 of the outer wall 22 where the noise attenuation device 20 is seated and the second shoulder 26 in the compressor cover 14 of a larger diameter that is deformed to secure the noise attenuation device 20 in the compressor cover 14. The second shoulder is located axially outward (e.g., further away from the compressor wheel) relative to the first shoulder 24. The noise attenuation device 20 has an annular mounting face 30 that seats on the first shoulder 24. When the second shoulder 26 is deformed, the mounting face 30 is contacted and engaged by the deformed portions of the second shoulder 26. The noise attenuation device 20 is preferably pressed steel that tapers inward or funnels inward from the mounting face 30 to complement the inner wall 32 of the compressor cover 14.

A method of retaining a noise attenuation device 20 in a compressor cover air inlet diameter of a turbocharger includes using a staking tool 40 (Figs. 11 and 12) that deforms compressor cover material (i.e. metal) to retain the noise attenuation device 20 within the air inlet 16. The noise attenuation device 20 is preferably a simple pressed steel design having mounting face 30 as shown in Figures 2 and 3, which can locate on a complementary compressor cover shoulder 24 as shown in Figure 7.

The compressor cover 14 has the first shoulder 24 that locates the noise attenuation device 20 (a loose tolerance is initially acceptable) and the second shoulder 26 that forms a diameter as a shelf for the indenters 42 of the staking tool 40 to locate and press. These shoulders 24 and 26 are preferably machined as inner diameters of the air inlet 16 as part of the outer wall 22 of the compressor cover 14. No other special machining of the compressor cover 14 is required to retain the noise attenuation device 20.

The staking tool 40 and an impactor (i.e. pedestal and/or press) can cause deformation of the compressor cover material around the noise attenuation device 20 and secure the noise attenuation device 20 in place. As shown in Figures 11 and 12, the staking tool 40 may be a hardened steel cylindrical tube with axially-protruding indenters 42 located at one end of the tube around the diameter of the tube. The indenters 42 can vary in number, shape, and pitch, wherein more indenters 42 are preferred for a larger diameter. In the illustrated embodiment, eight indenters 42 are equidistantly spaced around the circumference of the tube end. The indenters 42 are shaped to obtain the correct geometry in the compressor cover 14. For example, each indenter 42 has an outer surface 42a that forms an extension of the tube outer surface, and a concavely curved inner surface 42b. The indenter outer surface 42a and inner surface 42b intersect at a line edge 42c.

The staking tool 40 is preferably mounted vertically on a support shaft mechanism, such as a spindle. The spindle can be connected to a pedestal-type impactor, such as a lever operated, spring-loaded device for applying a specific impact load to the staking tool 40. Easy placement of the compressor cover 14 and the noise attenuation device 20 into the compressor cover 14 and then operating a lever, manually or automated, to actuate the staking tool 40 allow for speedy assembly. Figure 5 shows the staking tool 40 moving toward a noise attenuation device 20 to be seated and retained in a compressor cover 14 of a compressor housing 12. The staking process preferably includes mounting the compressor cover 14 with the air inlet section 16 facing upwardly so the noise attenuation device 20 can be simply dropped into the air inlet section 16.

Figure 6 shows a portion of a noise attenuation device 20 being moved toward a first shoulder 24 of a compressor cover 14. The noise attenuation device 20 can be placed adjacent to the first shoulder 24 for assembly, such as by dropping the noise attenuation device 20 into place on the first shoulder 24 of the compressor cover 14 in the air inlet section 16, which is preferably facing upwardly as shown in Figures 5 through 10.

Figure 7 shows a mounting face 30 of a noise attenuation device 20 being seated on a first shoulder 24 of compressor cover 14. The staking tool 40 moves toward the second shoulder 26 with the seated noise attenuation device 20 as shown in Figure 8. The indenters 42 align with the second shoulder 26.

Figure 9 shows an indenter 42 of a staking tool 40 being pressed into the second shoulder 26 adjacent to a noise attenuation device 20. The impact on the staking tool 40 forces the indenters 42 into the compressor cover material, and the staking tool 40 locally deforms the compressor cover material in a radially inward direction. The deformed material engages the mounting surface 30 to secure the noise attenuation device 20 in place in the compressor cover air inlet diameter.

Figure 10 shows the resulting deformation of the compressor cover 14 at the second shoulder 26 securing the noise attenuation device 20 to the outer wall 22 of the compressor cover 14.

Minimal load is applied on the noise attenuation device 20 away from the indenters 42 with this method of retention. When the material of the compressor cover 14 is deformed by the staking tool 40, the noise attenuation device 20 is securely fixed to the compressor cover 14 as only two parts without need for other operations, such as using adhesives.

The invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of words of description rather than limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.