Method for journal finishing of crankshafts, camshafts, and journals

• US 10,639,763 B2
• Filed: 11/14/2017
• Issued: 05/05/2020
• Est. Priority Date: 11/14/2017
• Status: Active Grant

• Current Assignee: Ford Motor Company
• Original Assignee: Ford Motor Company
• Inventors: Kopmanis, Michael A.
• Primary Examiner(s): Rose, Robert A
• Application Number:
  US15/813,076
• Publication Number:
  US 20190143472A1
• Time in Patent Office: 903 Days
• Field of Search: 451 49, 451 62, 451 57, 451450, 451 53, 451124, 451127, 451173
• CPC Class Codes: B24B 19/125 electrically controlled, e.g. numerically controlled
• CPC Class Codes: B24B 35/00 Machines or devices designed for superfinishing surfaces on work, i.e. by means of abrading blocks reciprocating with high frequency
• CPC Class Codes: B24B 5/42 for grinding crankshafts or crankpins
• CPC Class Codes: B24B 55/02 Equipment for cooling the grinding surfaces, e.g. devices for feeding coolant cooling or lubricating during dressing operation B24B53/095; incorporated in grinding wheels B24D
• CPC Class Codes: B24D 5/06 with inserted abrasive blocks, e.g. segmental
• CPC Class Codes: B24D 7/06 with inserted abrasive blocks, e.g. segmental
• CPC Class Codes: B24D 9/08 Circular back-plates for carrying flexible material

Abstract

A method of grinding a surface of a crankshaft is provided. The method includes grinding the surface of the crankshaft by a grinding wheel, and polishing the surface of the crankshaft ground by the grinding wheel by oscillating a polishing wheel in a transverse direction perpendicular to a longitudinal direction of the crankshaft.

Claims

1. A method of grinding a surface of a workpiece, the method comprising:

grinding the surface of the workpiece by a grinding wheel; and

polishing the surface of the workpiece ground by the grinding wheel by oscillating a polishing wheel at a frequency between 2-25 Hz in a transverse direction perpendicular to a longitudinal direction of the crankshaft.

2. The method according to claim 1, further comprising oscillating the polishing wheel at a stroke between 0.05-1.0 mm.

3. The method according to claim 1, further comprising applying a coolant during the polishing.

4. The method according to claim 3, wherein the coolant includes 6% water.

5. The method according to claim 1, wherein the polishing wheel is a cubic boron nitride (CBN) wheel.

6. The method according to claim 5, wherein the polishing wheel has a grain size between 15-76 microns.

7. The method according to claim 5, wherein the polishing wheel has 400 grit.

8. The method according to claim 5, wherein the polishing wheel is a vitrified CBN wheel.

9. The method according to claim 5, wherein the polishing wheel is a resin-bonded CBN wheel.

10. The method according to claim 1, wherein the polishing wheel removes stock material from the crankshaft at a depth of 20 microns.

11. The method according to claim 1, further comprising performing the grinding by plunge-grinding.

12. The method according to claim 11, wherein the plunge-grinding is performed by using a CBN wheel.

13. The method according to claim 11, wherein the CBN wheel for the plunge-grinding has a grain size of 151 microns.

14. The method according to claim 11, wherein the CBN wheel has 120 grit.

15. The method according to claim 1, wherein the surface is a surface of a main bearing journal or a pin journal of a crankshaft.

16. A method of grinding and polishing a surface of a crankshaft, the method comprising:

grinding the surface of the crankshaft by a grinding wheel; and

polishing the surface of the crankshaft ground by the grinding wheel by oscillating a vitrified or resin-bonded cubic boron nitride (CBN) wheel having a grain size no greater than 46 microns at a frequency between 2-25 Hz in a transverse direction perpendicular to a longitudinal direction of the crankshaft.

17. A method of grinding and polishing main bearing journals and pin journals of a crankshaft, the method comprising:

grinding the surface of the crankshaft by a grinding wheel; and

oscillating a polishing wheel at a stroke between 0.05-1.0 mm and a frequency between 2-25 Hz in a transverse direction perpendicular to a longitudinal axis of the crankshaft to polish the surface ground by the grinding wheel.

18. The method according to claim 17, wherein the polishing wheel has a grain size no greater than 46 microns.