Composite rotor for exhaust-gas turbochargers having titanium aluminide wheels

• US 20070033937A1
• Filed: 08/04/2006
• Published: 02/15/2007
• Est. Priority Date: 08/10/2005
• Status: Abandoned Application

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Fledersbacher, Peter, Scheydecker, Michael, Baur, Hartmut
• Application Number:
  US11/499,337
• Publication Number:
  US 20070033937A1
• Time in Patent Office: Days
• US Class Current: 60/605.100
• CPC Class Codes: F01D 5/02 Blade-carrying members, e.g. rotors rotors of non-bladed type F01D1/34; stators F01D9/00 ; selecting particular materials F01D5/28
• CPC Class Codes: F02C 6/12 Turbochargers, i.e. plants for augmenting mechanical power output of internal-combustion piston engines by increase of charge pressure
• CPC Class Codes: F05D 2220/40 in turbochargers

Abstract

A rotor for exhaust-gas turbochargers having a turbine wheel (3) made of a metal aluminide, a hollow shaft (2) made of steel or of a nickel-based alloy, and a compressor wheel (1), the compressor wheel (1) having a journal (5), which partially extends into the hollow shaft (2) made of steel or of nickel-based alloy and which forms a positive connection (6) with the same, as well as a method for manufacturing rotors for exhaust-gas turbochargers having a turbine wheel (3), a metal hollow shaft (2), and a compressor wheel (1), including the steps of substance-to-substance bonding of the turbine wheel (3) and of the metal hollow shaft (2), positively connecting the compressor wheel and the metal hollow shaft (2), the positive connection (6) being produced by a journal (5) of the compressor wheel (1) projecting into metal hollow shaft (2), and by the inside of the metal hollow shaft.

Claims

1. A rotor for exhaust-gas turbochargers comprising:

a turbine wheel made of a metal aluminide,

a hollow shaft made of steel or of a nickel-based alloy, and

a compressor wheel, the compressor wheel having a journal partially extending into the hollow shaft to form a positive connection with the hollow shaft.

2. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the positive connection is produced by edge forming or round kneading or by mechanical interlocking.

3. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein, for the positive connection, the journal and the hollow shaft are threadless.

4. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the hollow shaft on a side of the compressor wheel has at least one slot for corresponding driving elements on the journal.

5. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the compressor wheel lacks any recesses or material accumulations for balancing the rotor.

6. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the positive connection is designed to be releasable between the compressor wheel and the shaft.

7. The rotor for exhaust-gas turbochargers as recited in claim 6 wherein the connection is releasable by heating the hollow shaft and by cooling the compressor wheel made of aluminum alloy to a temperature difference of at least 300°

C.

8. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the connection between the hollow shaft and the turbine wheel is a substance-to-substance bond.

9. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the turbine wheel is made of a titanium aluminide.

10. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the connection between the hollow shaft and the turbine wheel is a welded connection.

11. The rotor for exhaust-gas turbochargers as recited in claim 1 wherein the compressor wheel is made of an aluminum alloy or of titanium aluminide.

12. A method for operating a rotor as recited in claim 1 comprising:

operating the rotor in in an exhaust gas system of a motor vehicle internal combustion engine at rotational speeds above 80,000 rpm.

13. A method for manufacturing rotors for exhaust-gas turbochargers having a turbine wheel, a metal hollow shaft, and a compressor wheel, the method comprising the steps of

substance-to-substance bonding of the turbine wheel and of the metal hollow shaft,

positively connecting the compressor wheel and the metal hollow shaft via a connection produced by a journal of compressor wheel projecting into the metal hollow shaft and contacting an inside of the hollow metal shaft.

14. The method as recited in claim 13 wherein the positive connection is produced by a mechanical action on an outside of the hollow shaft in the region of the journal.

15. The method as recited in claim 13 wherein the positive connection is produced by edge forming or round kneading of the metal hollow shaft.

16. The method as recited in claim 13 wherein the positive connection is produced by shrinking of the hollow shaft onto the journal.

17. The method as recited in claim 16 wherein, at a coldest operating point, the positive connection exhibits an overlap of the hollow shaft and the journal of 0.01 to 0.1 mm.

18. The method as recited in claim 13 wherein, during the process of forming the positive connection, a centering or a balancing of the rotor is carried out with respect to its longitudinal axis.

19. The method as recited in claim 13 wherein the turbine wheel and the metal hollow shaft are joined to one another in a friction-welding installation, and, subsequently thereto, the positive connection is produced between the metal hollow shaft and the compressor wheel in a same clamping installation or a same system.