Process for manufacturing a hollow roller and roller bearing including such a roller

Patent metadata

Field	Value
Publication number	US-10584749-B2
Application number	US-201715833463-A
Country	US
Kind code	B2
Filing date	Dec 6, 2017
Priority date	Jun 30, 2014
Publication date	Mar 10, 2020
Grant date	Mar 10, 2020

Abstract

A process for manufacturing a hollow roller of a roller bearing including steps of: machining an outer radial cylindrical surface, with a circular cross section centered on a first axis, and machining an inner radial cylindrical surface with a circular cross section centered on a second axis. These two steps are realized on the same lathe. The hollow roller is provided with the outer radial cylindrical surface, with a diameter of at least 5 mm, and the inner radial cylindrical surface. An offset between the first axis and the second axis, measured in the hollow roller between two axial surfaces of the hollow roller, is less than 2 μm, and an inclination angle between the first axis and the second axis is less than one minute of angle. The roller bearing comprises amongst others, at least one such hollow roller.

First claim

The invention claimed is:

1. A process comprising:
mounting a rod in a first rotatable chuck of a lathe;
machining an outer cylindrical surface of the rod such that the rod has a circular cylindrical cross section centered on a first axis;
without removing the rod from the first chuck, using a drill attached to a second rotatable chuck of the lathe to drill into an axial end face of the rod to form an inner radial cylindrical surface with a circular cross section centered on a second axis, the second axis being offset from the first axis by less than 2 pm,
after using the drill to drill into the axial end face of the rod, and without removing the rod from the first chuck, using a reamer attached to the lathe to ream the inner radial cylindrical surface,
without removing the rod from the first chuck, holding the rod with the second chuck and, while holding the rod with the first chuck and the second chuck, separating the machined portion of the rod from an unmachined portion of the part to form a hollow roller of a roller bearing, and
wherein the drilling occurs over a distance from the axial end face of the rod, wherein the outer cylindrical surface is machined over the distance from the axial end face of the rod such that the cross section centered on the first axis is substantially constant along the distance and wherein the separating occurs at a location such that the hollow roller has a constant inner diameter.

2. The process according to claim 1 , wherein the first axis is an axis of rotation of the first chuck and the second axis is an axis of rotation of the second chuck.

3. The process according to claim 1 , wherein the machining of the outer surface of the rod and the machining of the inner surface of the rod are performed such that the hollow roller has a hollowness rate above 78%.

4. The process according to claim 3 , wherein an inclination angle between the first axis and the second axis is less than one minute of angle.

5. The process according to claim 4 , including installing the hollow roller and a plurality of roller elements between a bearing inner ring and a bearing outer ring to form the roller bearing.

6. A process comprising:
providing a lathe having a first holder having a first axis of rotation and a second holder facing the first holder and having a second axis of rotation, the first axis of rotation being offset from the second axis of rotation by less than 2 pm and an inclination angle between the first axis of rotation and the second axis of rotation being less than one minute of angle;
placing a rod in the first holder and machining an outer surface of the rod to form a cylindrical outer surface having an outer circular cross section centered on the first axis of rotation;
without removing the rod from the first holder, machining an inner surface of the rod using a tool rotatably supported by the second holder to form a cylindrical inner surface having an inner circular cross section centered on the second axis of rotation;
without removing the rod from the first holder, holding the rod with the second holder and separating the machined portion of the rod from an unmachined portion of the rod to form a hollow roller of a roller bearing, and
wherein the rod has an axial end face, wherein the machining of an inner surface of the rod includes drilling into the axial end face of the rod, wherein the inner surface is machined over a distance from the axial end face of the rod, wherein the outer surface is machined over the distance from the axial end face of the rod to have a constant outer diameter and wherein the separating occurs at a location such that the hollow roller has a constant inner diameter.

7. The process according to claim 6 , wherein the machining of the outer surface of the rod and the machining of the inner surface of the rod are performed such that the hollow roller has a hollowness rate above 78%.

8. The process according to claim 7 , further including, after the separating of the machined portion of the rod from the unmachined portion of the rod,
grinding the outer cylindrical surface on a centerless machining equipment, or
grinding axial surfaces of the hollow roller, or
grinding connecting or corner radii between axial and radial surfaces of the hollow roller, or
grinding a draught zone or crown between the outer radial cylindrical surface and a zone including a connecting radius.

9. The process according to claim 7 , wherein:
the machining of the outer surface of the rod is performed by a cutting insert, and
the machining of the inner surface of the rod is performed by a drill.

10. The process according to claim 7 , wherein the first holder is a first chuck and wherein the second holder is a second chuck.

11. The process according to claim 7 , wherein the machining of the inner surface of the rod is performed simultaneously with the machining of the outer surface of the rod.

12. The process according to claim 7 , wherein the machining of the inner surface of the rod is performed after the machining of the outer surface of the rod.

13. The process according to claim 7 , wherein the separating is performed at a location at which the inner surface of the rod has been machined.

14. The process according to claim 7 , including installing the hollow roller and a plurality of roller elements between a bearing inner ring and an bearing outer ring to form a roller bearing.

15. The process according to claim 7 , including installing the hollow roller and a plurality of roller elements between a bearing inner ring and an bearing outer ring to form a roller bearing.

16. A process comprising:
providing a lathe having a first holder having a first axis of rotation and a second holder facing the first holder and having a second axis of rotation;
placing a rod in the first holder and machining an outer surface of the rod to form a cylindrical outer surface having an outer circular cross section centered on the first axis of rotation;
without removing the rod from the first holder, machining an inner surface of the rod using a tool rotatably supported by the second holder to form a cylindrical inner surface having an inner circular cross section centered on the second axis of rotation;
without removing the rod from the first holder, holding the rod with the second holder and separating the machined portion of the rod from an unmachined portion of the rod to form a hollow roller of a roller bearing;
installing the hollow roller and a plurality of roller elements between a bearing inner ring and a bearing outer ring to form the roller bearing, and
wherein the rod has an axial end face, wherein the machining of an inner surface of the rod includes drilling into the axial end face of the rod, wherein the inner surface is machined over a distance from the axial end face of the rod, wherein the outer surface is machined over the distance from the axial end face of the rod to have a constant outer diameter and wherein the separating occurs at a location such that the hollow roller has a constant inner diameter.

17. The process according to claim 16 , wherein the first axis of rotation is offset from the second axis of rotation by less than 2 μm and an inclination angle between the first axis of rotation and the second axis of rotation is less than one minute of angle.

Assignees

• Skf Ab

Inventors

• Carrerot Herve
• Jorgowsky Jacky

Classifications

• F16C2220/62

  by turning, boring, drilling · CPC title

• Y10T29/49679

  Anti-friction bearing or component thereof · CPC title

• F16C33/34 Primary

  Rollers; Needles · CPC title

• B24B5/01

  for combined grinding of surfaces of revolution and of adjacent plane surfaces on work · CPC title

• F16C2220/70

  by grinding · CPC title