Turbine rotor for an exhaust gas turbine and method for producing the turbine rotor

Patent metadata

Field	Value
Publication number	US-9869182-B2
Application number	US-201314389028-A
Country	US
Kind code	B2
Filing date	Mar 20, 2013
Priority date	Mar 29, 2012
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A turbine rotor for an exhaust gas turbine has a turbine rotor wheel made of a highly heat-resistant metal alloy and a rotor shaft made of steel. A rotor wheel hub and a rotor shaft end are connected to each other in a metallurgical bond by way of a solder connection. The rotor shaft end and/or the rotor wheel hub is formed with a central recess, which acts as a thermal choke. A closing plug is arranged in the respective recess, forming a closed cavity with the recess and closing off the recess toward the respective end face. The solder connection is formed between the end faces of the rotor wheel hub and the rotor shaft, between the closing plug and the rotor wheel hub, and between the closing plug and the rotor shaft.

First claim

The invention claimed is:

1. A turbine rotor for an exhaust gas turbine, the turbine rotor comprising:
a turbine rotor wheel consisting of a highly heat-resistant metal alloy, said rotor wheel having a rotor wheel hub with an end face;
a rotor shaft consisting of steel, said rotor shaft having a rotor shaft end with an end face facing toward said rotor wheel hub;
one or both of said rotor shaft end and said rotor wheel hub having a central recess formed therein configured to act as a thermal choke at a transition between said rotor wheel and said rotor shaft;
a closure plug disposed in a respective said recess to form a closed hollow cavity in said recess and closing off said hollow cavity in said recess toward the respective said end face and to form a planar surface with the respective said end face; and
a brazed connection forming a metallurgical bond connecting said rotor wheel hub and said rotor shaft end to one another, said brazed connection being formed of brazing material disposed between said end face of said rotor wheel hub and said end face of said rotor shaft, between said closure plug and said rotor wheel hub, and between said closure plug and said rotor shaft.

2. The turbine rotor according to claim 1 , wherein the highly heat-resistant metal alloy of said turbine rotor wheel is a TiAl alloy or an Ni-based alloy and said steel of said rotor shaft is a low-alloy or high-alloy heat-treatment steel or an austenitic steel.

3. The turbine rotor according to claim 1 , wherein said brazed connection is a connection formed by electron-beam brazing.

4. The turbine rotor according to claim 1 , wherein said closure plug is formed with a recess on at least one side facing the respective said cavity, for increasing a volume of the respective said cavity.

5. The turbine rotor according to claim 1 , wherein said closure plug is a cylindrical plug formed, on an outer lateral surface thereof, with depressions selected from the group consisting of grooves, slots, and knurls, each having at least in some proportion an axial extent.

6. The turbine rotor according to claim 1 , wherein said central recess in the rotor shaft end and/or in said rotor wheel hub is a blind-hole bore.

7. The turbine rotor according to claim 6 , wherein the respective said blind-hole bore is formed with an offset, which widens the bore toward the respective end face and acts as a stop for the respective said closure plug.

8. A method of producing a turbine rotor, the method comprising the following method steps:
providing workpieces, including a turbine rotor wheel of a highly heat-resistant metal alloy, a rotor shaft of steel, and a closure plug;
forming a central recess into one or both of an end face of the rotor shaft and an end face of a rotor wheel hub of the turbine rotor wheel;
inserting the closure plug into the central recess of the rotor shaft end or the rotor wheel hub to form a closed, hollow cavity between the closure plug and a bottom of the recess and to form a planar surface comprised of the closure plug and a respective end face of the rotor shaft or of the rotor wheel hub;
applying a brazing material to one of the end faces of the rotor wheel hub or the rotor shaft;
bringing together and centrally aligning the turbine rotor wheel and the rotor shaft by clamping the workpieces in a suitable device, with the end faces of the rotor wheel hub and the rotor shaft lying directly opposite one another and with the brazing material positioned in a brazing gap in between;
heating up the brazing material and the end face region of the rotor wheel hub and the rotor shaft at the brazing gap with an electron beam, up to a predetermined brazing temperature lying above a melting temperature of the brazing material;
maintaining the brazing temperature over a predetermined time, by way of a controlled supply of energy by the electron beam;
cooling down the workpieces and creating the brazed connection between the turbine rotor wheel and the rotor shaft; and
releasing the turbine rotor from the device.

9. The method according to claim 8 , which further comprises, after inserting the closure plug, applying a flux to the two end faces to be connected, of the rotor wheel hub and the rotor shaft, and the closure plug.

10. A turbine rotor for an exhaust gas turbine, the turbine rotor comprising:
a turbine rotor wheel consisting of a highly heat-resistant metal alloy, said rotor wheel having a rotor wheel hub with an end face;
a rotor shaft consisting of steel, said rotor shaft having a rotor shaft end with an end face facing toward said rotor wheel hub;
one or both of said rotor shaft end and said rotor wheel hub having a central recess formed therein configured to act as a thermal choke at a transition between said rotor wheel and said rotor shaft;
a closure plug disposed in a respective said recess to form a closed cavity in said recess and closing off said recess toward the respective said end face and to form a planar surface with the respective said end face; and
a brazed connection forming a metallurgical bond connecting said rotor wheel hub and said rotor shaft end to one another, said brazed connection being formed between said end face of said rotor wheel hub and said end face of said rotor shaft, between said closure plug and said rotor wheel hub, and between said closure plug and said rotor shaft.

Assignees

• Continental Automotive Gmbh

Inventors

• Albuzat Ulrike
• Muench Guenter

Classifications

• B23K1/18

  circumferential seams, e.g. of shells · CPC title

• F05D2230/237

  Brazing · CPC title

• F05D2220/40

  in turbochargers · CPC title

• B23K2101/001

  Turbines · CPC title

• B23K1/0056

  soldering by means of beams, e.g. lasers, electron beams [EB] · CPC title