WO2010035570A1

WO2010035570A1 - Rolling sliding member and process for producing same

Info

Publication number: WO2010035570A1
Application number: PCT/JP2009/063113
Authority: WO
Inventors: 佐田　隆; 松山　博樹
Original assignee: 株式会社ジェイテクト
Priority date: 2008-09-29
Filing date: 2009-07-22
Publication date: 2010-04-01
Also published as: JP2010078126A

Abstract

A collar surface (15a) of an inner ring (10) of a cylindrical roller bearing (1) and a collar surface (23a) of an outer ring (20) of the bearing (1) are constituted of hard chromium deposits (15 and 25). The hard chromium deposits (15 and 25) have been subjected to plastic working to crush out cracks generated in the hard chromium deposits (15 and 25). Thus, a rolling sliding member having high wearing resistance and seizing resistance has been realized.

Description

Rolling sliding member and manufacturing method thereof

The present invention relates to a rolling sliding member and a manufacturing method thereof.

In a roller bearing in which a plurality of rollers are arranged between a pair of bearing rings, sliding contact occurs at the contact portion between the raceway surface of the bearing ring and the end face of the roller. For this reason, when the supply amount of the lubricating oil to the roller bearing is insufficient, the contact portion with the end surface of the flange surface may be worn early or seizure may occur.

Therefore, a rolling bearing has been proposed in which a hard chrome plating layer is formed on at least one of the end face and the end face of the roller, and the surface of the contact portion is hardened (see, for example, Patent Document 1).

JP 2004-332915 A

However, fine cracks occur in the hard chrome plating layer. For this reason, the rolling bearings still have a defect that the cracks are the starting point due to sliding contact under high surface pressure, and wear or the like tends to occur on the flange surface or roller end surface.

This invention is made | formed in view of such a situation, and it aims at providing the rolling sliding member which can exhibit higher abrasion resistance, and its manufacturing method.

The rolling sliding member of the present invention is a rolling sliding member in which a hard chrome plating layer that is in rolling contact and / or sliding contact with a mating member is formed on the surface of a metal base material. The crack generated in the layer is crushed by plastic working.

In the rolling sliding member of the present invention, since the crack generated in the hard chrome plating layer formed by the hard chrome plating process is crushed by plastic processing, the occurrence of wear, seizure, etc. starting from the crack Can be suppressed.
Therefore, the rolling sliding member of the present invention can exhibit high wear resistance and seizure resistance, particularly against sliding contact and rolling contact under high surface pressure.

The base material may be a base material of a bearing ring of a rolling bearing or a base material of a rolling element.
Further, the base material may be a base material of a bearing ring of a roller bearing, and a surface of the hard chrome plating layer may be a flange surface provided on the bearing ring.
Further, the base material may be a base material of a rolling element for a roller bearing, and the hard chrome plating layer may be formed on an end surface of the base material of the rolling element.

The rolling sliding member manufacturing method of the present invention is the above-described rolling sliding member manufacturing method, in which a hard base is plated on a metal base material, and the surface of the intermediate material is in rolling contact with the mating member. After forming the hard chrome plating layer in sliding contact, the hard chrome plating layer is subjected to plastic working to crush cracks generated in the hard chrome plating layer.

The rolling sliding member manufacturing method of the present invention exhibits the above-described high wear resistance and seizure resistance because the cracks generated in the hard chrome plating layer formed by the hard chrome plating process are crushed by plastic working. A rolling sliding member can be obtained.

The plastic working is preferably shot peening or burnishing using a ball or roller. Thereby, the said crack can be crushed more effectively.

According to the present invention, there is an excellent effect that a rolling sliding member having high wear resistance can be obtained.

It is principal part sectional drawing of the cylindrical roller bearing which has a rolling sliding member which concerns on one Embodiment of this invention. It is a drawing substitute photograph which shows the cross-section of the part containing a hard chromium plating layer. It is a principal part expanded sectional view which shows the cross-section of the part containing the hard chromium plating layer shown by FIG. It is process drawing which shows the manufacturing method of the rolling sliding member which concerns on one Embodiment of this invention. It is principal part sectional drawing of the cylindrical roller bearing which has a rolling sliding member which concerns on other embodiment of this invention. 3 is a drawing-substituting photograph showing the surface of the test piece of Example 1. FIG. 6 is a drawing-substituting photograph showing the surface of a test piece of Comparative Example 3. FIG. It is a schematic explanatory drawing of the block on ring test of Test Example 2. 6 is a graph showing the shape of the surface of each test piece of Example 1 and Comparative Examples 1 to 3 after execution of Test Example 2.

[Rolling sliding member]
Hereinafter, a rolling sliding member according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an essential part showing an NUP type cylindrical roller bearing 1 including an inner ring (track ring) 10, an outer ring (track ring) 20 and a cylindrical roller (rolling element) 30 as rolling sliding members.

The inner ring 10 is a combination of an inner ring body 11 formed with an inner ring raceway surface 12 and a saddle wheel 13. A first flange 14 projects from the outer peripheral side of one axial end of the inner ring 10 and a second collar 15 projects from the other axial end. The first flange 14 is formed integrally with one end of the inner ring main body 11 in the axial direction, and the second flange 15 is formed by the outer periphery of the flange 13. When the

end surfaces

33a and 33b of the cylindrical roller 30 are in sliding contact with the

flange surfaces

14a and 15a of the first and

second flange portions

14 and 15, rolling of the cylindrical roller 30 is guided. The Further, the first and

second flange portions

14 and 15 can receive a thrust load acting on the cylindrical roller bearing 1.

In this embodiment, it is assumed that a thrust load having a high surface pressure is applied to the second flange 15. For this reason, at least the flange surface 15 a of the second flange portion 15 among the

flange surfaces

14 a, 15 a of the first and

second flange portions

14, 15 is constituted by the hard chromium plating layer 17. The hard chrome plating layer 17 is formed over the entire surface of the portion corresponding to the flange surface 15a of the base material 16 of the inner ring 10 (ring wheel 13).

The outer ring 20 has an outer ring raceway surface 22 formed on the inner peripheral side of the central portion in the axial direction, a third flange portion 23 formed at one axial end portion, and a fourth flange portion 24 formed at the other axial end portion. is there. Rolling of the cylindrical roller 30 is also guided by a part of the

end surfaces

33a and 33b of the cylindrical roller 30 slidingly contacting the

flange surfaces

23a and 24a of the third and

fourth flange portions

23 and 24. Is done. Also, the thrust load acting on the cylindrical roller bearing 1 can be received by the third and

fourth flange portions

23 and 24.

In this embodiment, it is assumed that a thrust load having a high surface pressure is applied to the third flange 23. For this reason, at least the flange surface 23 a of the third flange portion 23 among the

flange surfaces

23 a, 24 a of the third and

fourth flange portions

23, 24 is constituted by the hard chromium plating layer 25. The hard chrome plating layer 25 is formed over the entire surface of the portion corresponding to the flange surface 23 a of the base material 26 of the outer ring 20.

The thickness of each of the hard

chrome plating layers

17 and 25 is usually set to 10 to 20 μm. The hard chromium plating

layers

17 and 25 are compressed and deformed in the thickness direction by plastic working. Thereby, the crack C [refer FIG. 2 (A) and FIG. 3 (A)] which arose in the hard chromium plating

layers

17 and 25 formed by the hard chromium plating process is crushed [FIG. 2 (B) and See FIG. 3B]. That is, the gap extending in the depth direction of each of the hard chromium plating

layers

17 and 25 is closed by the plastic working. As described above, since the cracks C that can be the starting point of occurrence of wear, seizure, separation, etc. in the hard

chrome plating layers

17 and 25 are crushed, the

flange surfaces

15a and 23a are cylindrical rollers under high surface pressure. Even in the case of sliding contact with 30, high wear resistance and seizure resistance can be exhibited. Examples of the plastic processing include shot peening processing and burnishing processing described later.

[Production method of rolling sliding member]
Next, a method for manufacturing a rolling sliding member according to an embodiment of the present invention will be described with reference to FIG. 4 taking the outer ring 20 of the cylindrical roller bearing 1 shown in FIG. 1 as an example.
In this manufacturing method, first, forging, turning, heat treatment, and grinding are performed in this order on a material made of SUJ2, which is a bearing steel, and the base material of the outer ring 20 having the third and

fourth flange portions

23, 24. 26 is formed. The outer peripheral surface, end surface, raceway surface 22 and flange surface 24a of the fourth flange portion 24 are subjected to the grinding process. Further, the grinding process is also applied to a portion corresponding to the flange surface 23 a of the third flange portion 23 of the base material 26.

Next, hard chrome plating is applied to the surface of the base material 26 corresponding to the flange surface 23a of the third flange portion 23 to form a hard chromium plating layer 25 that is in sliding contact with the end surface 33a of the cylindrical roller 30. To do.
The hard chrome plating layer 25 can be formed by electrolytic hard chrome plating.

Thereafter, the cracks in the hard chrome plating layer 25 are crushed by plastic working. Examples of this plastic working include shot peening using fine particles and burnishing using balls or rollers. Among these, shot peening using fine particles is preferable from the viewpoint of easy processing. The shot peening process using fine particles can be performed, for example, by projecting steel beads having a particle size of 30 to 100 μm onto the hard chromium plating layer 25 at a projection pressure of 0.3 to 0.5 MPa.
Then, the target outer ring 20 can be obtained by superfinishing the portion corresponding to the raceway surface 22 of the base material 26.

In the embodiment described above, the hard chromium plating layers 17 and 25 subjected to plastic working are formed on the second flange 15 of the inner ring 10 and the third flange 23 of the outer ring 20, respectively. Instead, as shown in FIG. 5, hard chromium plating layers 34 and 35 may be formed on both end surfaces 33 a and 33 b of the base material 32 of the cylindrical roller 30. In short, the hard chrome plating layer may be formed in a portion to which a thrust load is applied.

Further, the present invention can be applied to a tapered roller bearing in addition to various cylindrical roller bearings such as NU type, NJ type, N type, NF type, and NH type.
Further, the present invention can be applied to a member that causes rolling contact such as a cam follower, and a member that causes both rolling contact and sliding contact such as a gear.

Next, the rolling sliding member of the present invention will be described with reference to examples and comparative examples.
[Example 1 and Comparative Examples 1 to 3]
A block heat-cured to a Rockwell C hardness of 60 to 63 made of SUJ2 was prepared, and this block was ground to obtain a test piece of Comparative Example 1 (surface roughness Ra: 0.22 μm). .

The same test piece as Comparative Example 1 was produced, and the surface thereof was lapped to obtain the test piece of Comparative Example 2 (surface roughness Ra: 0.01 μm).

The same test piece as Comparative Example 2 was prepared, and the hard chromium plating layer was formed on the lapping surface by electrolytic hard chromium plating, and the test piece of Comparative Example 3 (Vickers hardness of the plating layer: 920 to 950, Surface roughness Ra: 0.02 μm).

The same specimen as Comparative Example 3 was prepared, and WPC treatment (registration) was performed by projecting fine particles (steel beads) with a particle size of 30 to 100 μm onto the hard chromium plating layer at a projection pressure of 0.3 to 0.5 MPa. (Trademark) [fine particle peening] was performed, and cracks generated in the hard chromium plating layer were crushed by plastic deformation. The block after the shot peening process was used as the test piece of Example 1 (Vickers hardness of the plating layer: 1030 to 1080, surface roughness Ra: 0.10 μm).

[Test Example 1]
Observation of Test Piece Surface The surfaces of the test pieces of Example 1 and Comparative Example 3 were observed with an electron microscope. A drawing-substituting photograph showing the surface of the test piece of Example 1 is shown in FIG. Moreover, the drawing substitute photograph which shows the surface of the test piece of the comparative example 3 is shown in FIG. In the drawing, (B) is an enlarged view of the surface of the test piece shown in (A).

From the results shown in FIGS. 6 and 7, the test piece of Comparative Example 3 subjected to hard chrome plating has large cracks on the surface (FIG. 7), but the hard chrome plating layer was subjected to shot peening. It can be seen that in the test piece of Example 1, the cracks on the surface have disappeared or have been refined (FIG. 6).

[Test Example 2]
Sliding Wear Test A sliding wear test of the test pieces of Example 1 and Comparative Examples 1 to 3 was performed by a block-on-ring test (see FIG. 8). The block on ring test was performed as follows.
A part of SUJ ring 11 having a Rockwell C hardness of 60 to 63 and a surface roughness Ra of 0.2 μm is placed in an oil bath (VG68 mineral oil, bath temperature: 40 ° C.). 11 was rotated in the direction of the arrow for 30 minutes at a sliding speed of 0.3 m / s. Then, the test piece 12 is arranged on the rotating ring 11 and a load is applied from above the test piece 12 so as to obtain a contact surface pressure of 443 MPa to bring the test piece 12 and the ring 11 into contact with each other. It was.
The shape of the surface of the test piece was measured using a stylus type surface roughness measuring machine. A graph showing the shape of the surface of each test piece of Example 1 and Comparative Examples 1 to 3 is shown in FIG. In the figure, (A) is the shape of the surface of the test piece of Example 1, (B) is the shape of the surface of the test piece of Comparative Example 1, and (C) is the shape of the surface of the test piece of Comparative Example 2. , (D) shows the shape of the surface of the test piece of Comparative Example 3. Table 1 shows the wear depth of each test piece shown in the graph shown in FIG.

From the results shown in FIG. 9 and Table 1, the wear depth of the test piece of Example 1 is 0.2 μm or less (below the measurement limit), compared with the wear depth of the test pieces of Comparative Examples 1 to 3. I understand that it is small. In particular, the wear depth of the test piece of Example 1 is smaller than the wear depth of the test piece of Comparative Example 3 (FIG. 9D) subjected to hard chrome plating. As shown in FIG. 1, it is understood that high wear resistance can be obtained by subjecting the hard chromium plating layer to shot peening and crushing the crack generated on the surface by plastic deformation.

DESCRIPTION OF SYMBOLS 1 Cylindrical roller bearing, 10 Inner ring (track ring), 11 Inner ring main body, 14 1st collar part, 14a Saddle face, 15a saddle face, 16 Inner ring base material, 17 Hard chromium plating layer, 20 Outer ring (track ring), 23a鍔 surface, 24a 鍔 surface, 25 hard chrome plating layer, 26 outer ring base material, 30 cylindrical roller (rolling element), 32 cylindrical roller base material, 33a end surface, 33b end surface, 34 hard chrome plating layer, 35 hard chrome plating Layer, C crack

Claims

A rolling sliding member in which a hard chromium plating layer that is in rolling contact and / or sliding contact with a mating member is formed on the surface of a metal base material,
A rolling sliding member, wherein a crack generated in the hard chromium plating layer is crushed by plastic working.
The rolling sliding member according to claim 1, wherein the base material is a base material of a bearing ring of a rolling bearing or a base material of a rolling element.
The rolling sliding member according to claim 1, wherein the base material is a base material of a bearing ring of a roller bearing, and a surface of the hard chrome plating layer is a flange provided on the bearing ring.
The rolling sliding member according to claim 1, wherein the base material is a base material of a rolling element for a roller bearing, and the hard chromium plating layer is formed on an end surface of the base material of the rolling element.
It is a manufacturing method of the rolling sliding member according to claim 1,
After applying a hard chrome plating to a metal base material and forming a hard chrome plating layer in rolling contact and / or sliding contact with the mating member on the surface of the intermediate material, plastic processing is applied to the hard chrome plating layer. A method for producing a rolling sliding member, characterized by crushing a crack generated in the hard chromium plating layer.
The method of manufacturing a rolling sliding member according to claim 5, wherein the plastic working is shot peening or burnishing using a ball or a roller.