Method of manufacturing a sliding camshaft

Patent metadata

Field	Value
Publication number	US-9828650-B2
Application number	US-201615015739-A
Country	US
Kind code	B2
Filing date	Feb 4, 2016
Priority date	Feb 4, 2016
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A method of manufacturing a sliding camshaft for an internal combustion engine includes providing the sliding camshaft from a steel alloy having a carbon content between 0.25% and 0.60%. The sliding camshaft is then processed with a carbon infusing heat treatment process, such as carburization or carbonitriding. After the sliding camshaft has been processed with the carbon infusing heat treatment process, the sliding camshaft is then processed with a quenching heat treatment process, such as a mar-quenching heat treatment process.

First claim

The invention claimed is:

1. A method of manufacturing a sliding camshaft for an internal combustion engine, the method comprising:
providing the sliding camshaft from a steel alloy having a carbon content between 0.25% and 0.60% by weight;
processing the sliding camshaft with a carbon infusing heat treatment process; and
processing the sliding camshaft with a quenching heat treatment process after the sliding camshaft has been processed with the carbon infusing heat treatment process;
wherein processing the sliding camshaft with the quenching heat treatment process is further defined as processing the sliding camshaft with a mar-quenching heat treatment process, which includes:
heating the sliding camshaft to a quenching temperature;
submersing the sliding camshaft in a bath of oil; and
pre-heating the bath of oil to a temperature of at least 200° C. prior to submersing the sliding camshaft in the bath of oil.

2. The method set forth in claim 1 wherein the steel alloy includes between 0.5% and 2% by weight Chromium, between 0.5% and 2.0% by weight Manganese, between 0% and 3.5% by weight Nickel, between 0% and 0.8% by weight Molybdenum, between 0% and 0.1% by weight Silicon, a maximum of 0.1% by weight Sulfur, and a maximum of 0.05% by weight Phosphorous.

3. The method set forth in claim 1 wherein processing the sliding camshaft with the carbon infusing heat treatment process includes heating the sliding camshaft to a carburizing temperature in the presence of a carbon bearing material.

4. The method set forth in claim 3 wherein the carburizing temperature is between 900° C. and 1100° C.

5. The method set forth in claim 3 wherein processing the sliding camshaft with the carbon infusing heat treatment process includes maintaining the temperature of the sliding camshaft at the carburizing temperature in the presence of the carbon bearing material for a pre-determined period of time.

6. The method set forth in claim 5 wherein the pre-determined period of time is between 3 hours and 6 hours.

7. The method set forth in claim 1 wherein the carbon infusing heat treatment process is either a gas carburizing process, a low pressure carburizing process, or a carbonitriding process.

8. The method set forth in claim 1 wherein the quenching temperature is between 150° C. and 300° C.

9. The method set forth in claim 1 wherein pre-heating the bath of oil to a temperature of at least 200° C. is further defined as pre-heating the bath of oil to a temperature between 230° C. and 270° C.

10. The method set forth in claim 1 wherein processing the sliding camshaft with the mar-quenching heat treatment process includes maintaining the sliding camshaft in the bath of oil until the temperature of the sliding camshaft is uniform throughout all sections of the sliding camshaft and substantially equal to the temperature of the bath of oil.

11. The method set forth in claim 10 further comprising cooling the sliding camshaft to an ambient temperature after all sections of the sliding camshaft have cooled to the temperature of the bath of oil.

12. A method of manufacturing a sliding camshaft for an internal combustion engine, the method comprising:
providing the sliding camshaft from a steel alloy having a Carbon content between 0.25% and 0.60% by weight, a chromium content between 0.5% and 2% by weight, a Manganese content between 0.5% and 2.0% by weight, a Nickel content between 0% and 3.5% by weight, a Molybdenum content between 0% and 0.8% by weight, a Silicon content between 0% and 0.1% by weight, a maximum Sulfur content of 0.1% by weight, and a maximum Phosphorous content of 0.05% by weight;
processing the sliding camshaft with a carbon infusing heat treatment process;
wherein processing the sliding camshaft with the carbon infusing heat treatment process includes maintaining the temperature of the sliding camshaft at the carburizing temperature in the presence of the carbon bearing material for a pre-determined period of time of between 3 hours and 6 hours; and
processing the sliding camshaft with a mar-quenching heat treatment process after the sliding camshaft has been processed with the carburizing heat treatment process;
wherein processing the sliding camshaft with the mar-quenching heat treatment process includes heating the sliding camshaft to a quenching temperature of between 150° C. and 300° C., and then submersing the sliding camshaft in a bath of oil pre-heated to a temperature of between 230° C. and 270° C.

13. The method set forth in claim 12 wherein processing the sliding camshaft with the carbon infusing heat treatment process includes heating the sliding camshaft to a carburizing temperature of between 900° C. and 1100° C., in the presence of a carbon bearing material.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Li Huaxin
• Clever Glenn E

Classifications

• C21D9/30 Primary

  for crankshafts; for camshafts · CPC title

• C22C38/44

  with molybdenum or tungsten · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• C21D6/004

  containing Cr and Ni · CPC title

• C21D6/005

  containing Mn · CPC title