MECHANICAL SYSTEM COMPRISING A SHAFT COUPLED TO A BEARING, AND METHOD FOR MANUFACTURING SUCH A SYSTEM

• US 20200132111A1
• Filed: 07/03/2018
• Published: 04/30/2020
• Est. Priority Date: 07/03/2017
• Status: Active Grant

• Current Assignee: HEF USA
• Original Assignee: HEF USA
• Inventors: DIEW, Mohamadou Bocar, GACHON, Yves Rene Alexis, PROST, Fabrice
• Granted Patent: US 11,624,399 B2
• Time in Patent Office: Days
• CPC Class Codes: F02F 3/00 Pistons
• CPC Class Codes: F05C 2201/0448 Steel
• CPC Class Codes: F16C 11/02 Trunnions; Crank-pins fastening crank-pins to webs, crank-pins integral with cranks F16C3/06, F16C3/22
• CPC Class Codes: F16C 2202/04 Hardness
• CPC Class Codes: F16C 2202/50 Lubricating properties
• CPC Class Codes: F16C 2204/10 Alloys based on copper
• CPC Class Codes: F16C 2206/04 Diamond like carbon [DLC]
• CPC Class Codes: F16C 2223/30 Coating surfaces in general B05C, C23C
• CPC Class Codes: F16C 2240/44 Hole or pocket sizes
• CPC Class Codes: F16C 2360/22 Internal combustion engines in general F02B
• CPC Class Codes: F16C 33/043 Sliding surface consisting mainly of ceramics, cermets or hard carbon, e.g. diamond like carbon [DLC]
• CPC Class Codes: F16C 33/1065 Grooves on a bearing surface for distributing or collecting the liquid
• CPC Class Codes: F16C 9/04 Connecting-rod bearings; Attachments thereof
• CPC Class Codes: F16J 1/16 with gudgeon-pin; Gudgeon-pins

Abstract

The present invention relates to a mechanical system (1), comprising a bearing (4) and a shaft (10) coupled to the bearing (4), especially for an internal combustion engine, being subjected to average contact pressures of less than 200 MPa. The shaft (10) has at least one area (12) provided with an anti-seizing surface coating (20), having a surface hardness at least twice that of the bearing (4), and a microtexturation (30) comprised of a set of individual microcavities (31), distributed in said area (12). The invention also relates to a method for manufacturing such a mechanical system (1).

Claims

1. A mechanical system (1) comprising a bearing (4) and a shaft (10) coupled to the bearing (4), equipping an internal combustion engine, and subjected to mean contact pressures less than 200 MPa, wherein the shaft (10) comprises at least one area (12) provided with:

an anti-seizure surface coating (20), having a surface hardness at least twice that of the bearing (4), and

a microtexturing (30) formed by a set of separated microcavities (31, 32, 33, 34, 35), distributed within said area (12).

2. A mechanical system (1) according to claim 1, wherein the anti-seizure surface coating (20) of the shaft (10) has a surface hardness at least three times that of the bearing (4).

3. A mechanical system (1) according to claim 2, wherein the anti-seizure surface coating (20) of the shaft (10) has a surface hardness at least six times that of the bearing (4).

4. A mechanical system (1) according to claim 1, wherein each of the microcavities (31, 32, 33, 34, 35) having has a greatest length of between 15 and 100 micrometers, and a depth of between 50 nm and 100 μ

m.

5. A mechanical system (1) according to claim 4, wherein each of the microcavities (31, 32, 33, 34, 35) has a form ratio less than or equal to 1, defined as the ratio between the depth and the greatest length.

6. A mechanical system (1) according to claim 1 wherein the microcavities (31, 32, 33, 34, 35) are distributed within said area (12) with a surface density of between 5 and 30%, that surface density being defined as the ratio of the total area covered by the microcavities (31, 32, 33, 34, 35) to the total area of said area (12) including those microcavities (31, 32, 33, 34, 35).

7. A mechanical system (1) according to claim 1, wherein the microcavities (31, 32, 33, 34, 35) are distributed within said area (12) in a predetermined pattern so as to form a rectangular, square, triangular, or hexagonal network of microcavities on the surface, with spacing between the center of a microcavity and the centers of neighboring microcavities within a single pattern that are between 1 and 10 times the value of one of the longitudinal dimensions of the microcavities.

8. A mechanical system (1) according to claim 1, wherein the microcavities (31, 32, 33, 34, 35) are distributed within said area (12) in a random pattern, with spacing between the center of a microcavity and the centers of neighboring microcavities that are randomly between 0.1 and 10 times the value of one of the longitudinal dimensions of the microcavities.

9. A mechanical system (1) according to claim 1, wherein the shaft (10) has a cylindrical outer surface (11) fully covered by the surface coating (20) and the microtexturing (30).

10. A mechanical system (1) according to claim 1, wherein the shaft (10) has a cylindrical outer surface (11) comprising a single localized area (12) covered by the surface coating (20) and the microtexturing (30), that area (12) at least partially covering the portion of the surface (11) intended to rub against the bearing (4).

11. A mechanical system (1) according to claim 1 wherein the shaft (10) has a cylindrical outer surface (11) comprising several distinct areas (12) covered by the surface coating (20) and the microtexturing (30), those areas (12) at least partially covering the portion of the surface (11) intended to rub against the bearing (4).

12. A method for manufacturing a mechanical system (1),

manufacturing a mechanical system (1) comprising a bearing (4) and a shaft (10) coupled to the bearing (4), equipping an internal combustion engine, and subjected to mean contact pressures less than 200 MPa, wherein the shaft (10) comprises at least one area (12) provided with:

an anti-seizure surface coating (20), having a surface hardness at least twice that of the bearing (4), and

a microtexturing (30) formed by a set of separated microcavities (31, 32, 33, 34, 35), distributed within said area (12);

coating the shaft (10) by applying the anti-seizure surface coating (20) within said area (12) of the shaft (10), and

microtexturing the shaft (10) by forming all of the microcavities (31, 32, 33, 34) within said area (12) of the shaft (10).

13. A method according to claim 12, wherein the coating step is carried out before the microtexturing step.

14. A method according to claim 12, wherein the microtexturing step is carried out before the coating step.

15. A method according to claim 12, wherein the microtexturing step is carried out with a microtexturing installation maintaining constant settings.

16. A method according to claim 12, wherein the microtexturing step is carried out with a microtexturing installation successively configured with two different settings, or is successively carried out with two microtexturing installations having different settings, so that all of the microcavities (31, 32, 33, 34, 35) comprise at least a first type of microcavities (31) and a second type of microcavities (34;

35) having different geometries.