Borgwarner Inc.

B{dot Over (o)}rgwarner, Inc.

David Michael Decker

Stephen I Roby

Dietmar Metz

Steve Roby

Steven Roby

A turbocharger including, a turbine wheel (), a shaft () attached to the turbine wheel (), and a compressor wheel () disposed on the shaft () opposite the turbine wheel (). The compressor wheel () includes a back wall () and an axial bore () and a pilot washer () is located adjacent the compressor wheel back wall (). The pilot washer () has an inner diameter () and an outer diameter (), and includes a conical pilot ring () that extends into the axial bore () of the compressor wheel (). The pilot washer () includes a slit () extending from the inner diameter () to the outer diameter (). A nut () is threaded to the shaft () and is operative to provide an axial clamping force on the compressor wheel (), thereby causing the pilot washer () to contract onto the shaft () as the pilot ring () extends into the bore ().

Compressor wheel with balance correction and positive piloting

Articles that are cast from a particular titanium alloy can achieve a relatively high fatigue strength. The titanium alloy is an (&#x3b1;+&#x3b2;) titanium alloy that has a nominal composition of about 5.5 to about 6.63 mass percent aluminum, about 3.5 to about 4.5 mass percent vanadium, about 1.0 to about 2.5 mass percent chromium, maximum of 0.50 mass percent iron, about 0.15 to about 0.25 mass percent oxygen, about 0.06 to about 0.12 mass percent silicon, and at least 80 mass percent titanium or the balance titanium (Ti) with the exception of some allowable impurities. In one exemplary application, this titanium alloy may be used to cast a turbocharger compressor wheel.

Fatigue resistant cast titanium alloy articles

An air boost device such as a turbocharger, wherein the compressor wheel thereof is re-designed to permit die inserts (), which occupy the air passage and define the blades () during a process of forming a wax pattern () of a compressor wheel, to be pulled without being impeded by the blades. This modified blade design enables the automated production of wax patterns () using simplified tooling. The compressor wheel improves low cycle fatigue, withstands high temperatures and temperature changes, and permits operation at high boost pressure ratio while, on the other hand, having low weight, low inertial drag, and high responsiveness.

Turbocharger including cast titanium compressor wheel

A compressor wheel () for an air boost device and a method for designing the wheel are provided. The compressor wheel () comprises a hub () and a plurality of blades () connected to the hub (). The plurality of blades () have a ratio (f/N) of natural frequency to maximum rotational speed of less than 4.0 and are made from a titanium alloy. The plurality of blades () can comprise a plurality of full blades () and a plurality of splitter blades ().

Low blade frequency titanium compressor wheel

A vane () is provided which reduces leakage of gas in a variable geometry turbocharger () from the high pressure side of the vane () to the low pressure side of the vane (). The vane () can have a channel () along a gas bearing surface () for reducing the leakage. The channel () can be defined at least in part by sideplates (). The sideplates () can be integrally cast with the rest of the vane (). At least one of the sideplates () can have a hole therein for a vane shaft () which allows movement of the vane () for gas flow control. The sideplates () can have edges () that conform to the shape of the gas bearing surface ().

Turbocharger vane

Titanium aluminide (TiAl) rotor shaft assembly () of a type used in a turbocharger has a TiAl rotor () with an axially protruded portion () that is fixedly joined to a recessed portion () of a metal shaft () by the synergistic combination of an interference fit, such as a heat shrinkage fit, further supported by a brazed joint () in which a thin layer of a brazing material () is interposed between the surface of the protruded portion () and the recessed surface (). Optionally, one or both of the jointed surfaces have braze channels () to facilitate braze flow within the joint. Methods for producing the rotor shaft assembly () and a turbocharger having the rotor shaft assembly () are provided.

Titanium aluminide wheel and steel shaft connection thereto

A rotor shaft assembly () of a type used in a turbocharger, manufactured by mounting a powder compact () of a titanium aluminide rotor () to a pre-formed steel shaft (), and sintering the combination, which provides a strong metallurgical bond between the shaft () and rotor (). There is provided a rotor shaft assembly () and an inexpensive and efficient method of its manufacture, for an assembly capable of withstanding the high forces and fluctuating temperatures within a turbocharger.

Metal injection molded turbine rotor and metal shaft connection attachment thereto

A method of making an air boost device, wherein a compressor wheel incorporated therein is re-designed to permit die inserts (), which occupy the air passage and define the blades () during a process of forming a wax pattern () of a compressor wheel, to be pulled without being impeded by the blades. This modified blade design enables the automated production of wax patterns () using simplified tooling. These wax patterns () can be used in a large-scale investment casting process, and produce an economical cast titanium compressor wheel which performs aerodynamically at high boost pressure/RPM.

Method of making turbocharger including cast titanium compressor wheel

The difficulty of working with titanium has inhibited the adoption of titanium compressor wheels in automotive air boost devices. The invention provides an economical process for the manufacture of titanium compressor wheels. A hybrid process is disclosed, wherein a forging process is used to produce a near net shape pattern including filled in areas ( ) which must be subsequently machined or milled away to produce the net shape compressor wheel. Using the hybrid or two-step process, the technical complexity and time investment in each step is greatly reduced, flaws as associated with the casting technique are eliminated, the process allows itself to be fully automated, the dimensional accuracy of the final product is greater than with conventional techniques, and the strength of the compressor wheel is increased as compared to cast product.

Process for manufacturing forged titanium compressor wheel

A compressor wheel is re-designed to permit die inserts ( ), which occupy the air passage and define the blades ( ) during a process of forming a wax pattern ( ) of a compressor wheel, to be pulled without being impeded by the blades. This modified blade design enables the automated production of wax patterns ( ) using simplified tooling. These wax patterns ( ) can be used in a large-scale investment casting process, and produce an economical cast titanium compressor wheel which performs aerodynamically at high boost pressure/RPM. The compressor wheel improves low cycle fatigue, withstands high temperatures and temperature changes, and permits operation at high boost pressure ratio while, on the other hand, having low weight, low inertial drag, and high responsiveness. An economical method for operating an internal combustion engine, comprising providing the engine with an easily manufactured, long-life titanium compressor wheel and driving the titanium compressor wheel at high RPM for increasing combustion air throughput and density.

Cast titanium compressor wheel

A compressor wheel is re-designed to permit die inserts ( ), which occupy the air passage and define the blades ( ) during a process of forming a wax pattern ( ) of a compressor wheel, to be pulled without being impeded by the blades. This modified blade design enables the automated production of wax patterns ( ) using simplified tooling. These wax patterns ( ) can be used in a large-scale investment casting process, and produce an economical cast titanium compressor wheel which performs aerodynamically at high boost pressure/RPM. The compressor wheel improves low cycle fatigue, withstands high temperatures and temperature changes, and permits operation at high boost pressure ratio while, on the other hand, having low weight, low inertial drag, and high responsiveness. The invention further concerns an economical method for operating an internal combustion engine, comprising providing said engine with an easily manufactured, long-life titanium compressor wheel and driving the titanium compressor wheel at high RPM for increasing combustion air throughput and density.

Cost considerations have prevented the use of titanium compressor wheels ( ) in automotive air boost devices. A hybrid process is disclosed, wherein a wax pattern used in the investment casting process is intentionally designed not to produce a final (net shape) compressor wheel, but rather, is designed to produce a near net shape pattern including filled in areas ( ) which must be subsequently machined or milled away to produce the desired non-pullable shape compressor wheel. Surprisingly, when forming a titanium compressor wheel using the hybrid or two-step process, the technical complexity of each step (pattern forming and machining) is substantially lower, distortion of the wax blades ( ) during pattern casting is reduced, casting of titanium is simplified, the process allows itself to be fully automated, and the dimensional accuracy of the final product is greater than with conventional techniques.

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Arden, NC, United States of America

David Michael Decker