JP2004232838A - Rolling sliding component and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling sliding component and its manufacturing method, capable of increasing the strength in comparison with a conventional sliding member. <P>SOLUTION: Carbide is approximately uniformly deposited onto a rolling sliding surface by performing the carburizing treatment onto a component material made out of steel including C of 0.2 wt.% or more with the specific shape. A plurality of holes are formed by eliminating the carbide by electropolishing the surface. A hole diameter is 1-3 μm, an area ratio of the holes is 10-50 %, and the holes are impregnated with a lubricant with pressure. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rolling and sliding component and a method of manufacturing the same, and more particularly, to a rolling component having a rolling surface or a sliding component having a sliding surface and a method of manufacturing the same.
[0002]
In this specification, the rolling and sliding parts refer to pure rolling contact, pure sliding contact, and parts in which rolling contact and sliding contact are mixed.
[0003]
[Prior art]
Conventionally, as a sliding part, ferritic stainless steel containing 0.04 wt% of C is subjected to vacuum carburizing treatment, and then electrolytically etched in an oxalic acid aqueous solution to be porous, and a lubricant is filled in these holes. What is filled is known (for example, refer to Patent Document 1).
[0004]
[Patent Document 1]
JP-A-2-240298 (page 9, lower right column, line 9 to page 3, upper left column, line 13)
[0005]
[Problems to be solved by the invention]
However, in the above-mentioned sliding part, the structure is made of ferrite, and a large number of holes are in communication with each other as described in page 2, lower right column, line 18 to page 3, upper left column, line 1 of Patent Document 1. Therefore, the strength is reduced, and it is difficult to apply to sliding parts and rolling bearing parts used under high surface pressure.
[0006]
An object of the present invention is to solve the above-mentioned problems and to provide a rolling / sliding component having increased strength as compared with the above-described conventional sliding component, and a method of manufacturing the same.
[0007]
Means for Solving the Problems and Effects of the Invention
The rolling / sliding component according to the invention of claim 1 is a rolling / sliding component having a rolling surface and a sliding surface, wherein the rolling / sliding component is made of steel containing 0.2% by weight or more of C, and the rolling and sliding surface has a carbide. Are formed, and a plurality of holes are formed, and the holes are filled with a lubricant.
[0008]
According to the invention of claim 1, the C content in the steel is 0.2 wt% or more, the strength is increased, and the rolling and the holes formed on the sliding surface are independent of each other and too deep. As a result, the strength of the sliding component is increased as compared with the above-described conventional sliding component because the strength of the sliding component is reduced due to the reduction in strength due to the holes. Therefore, in addition to the sliding component used at a high surface pressure, it can be used for a bearing ring or a rolling element of a rolling bearing which is often used at a higher surface pressure and requires fatigue resistance.
[0009]
A rolling and sliding component according to a second aspect of the present invention is the rolling component according to the first aspect, wherein the carbide is formed by subjecting the steel to a carburizing treatment. In this case, by setting the carburizing condition, it is easy to optimize the carbide state (size, amount) of the surface layer.
[0010]
A rolling and sliding component according to a third aspect of the present invention is the rolling or sliding component according to the first or second aspect of the present invention, wherein the diameter of the hole is 1 to 3 μm and the area ratio is 10 to 50%. In this case, lubricity can be ensured without a decrease in material strength.
[0011]
Here, the area ratio is a ratio of an area occupied by carbide in a predetermined area of a rolling and sliding surface, and the surface can be enlarged and observed, and can be measured by image processing.
[0012]
A method for manufacturing a rolling and sliding component according to the invention of claim 4 is a method for manufacturing a rolling and sliding component having a rolling surface and a sliding surface, wherein the steel is formed into a predetermined shape by steel containing 0.2 wt% or more of C. By subjecting the formed component material to carburizing treatment, the rolling, after substantially uniformly depositing carbide on the sliding surface, a plurality of holes are formed by electrolytically polishing the surface to remove the carbide, Next, a lubricant is filled in the holes.
[0013]
According to the invention of claim 4, by performing carburizing treatment on a component material formed into a predetermined shape by steel containing 0.2 wt% or more of C, carbides are substantially uniformly deposited on the rolling and sliding surfaces. After that, a plurality of holes are formed by electrolytically polishing the surface to remove carbides, and then the holes are merely filled with a lubricant. It can be manufactured at low cost.
[0014]
According to a fifth aspect of the present invention, there is provided a method of manufacturing a rolling and sliding component according to the fourth aspect, wherein an oxalic acid aqueous solution is used as an electrolytic solution for the electropolishing. In this case, the carbide can be removed preferentially.
[0015]
According to a sixth aspect of the present invention, in the method for manufacturing a rolling and sliding component according to the fourth or fifth aspect, the lubricant is filled in the hole by impregnating the molten lubricant with pressure in the hole. Things. In this case, by applying pressure, a sufficient amount of lubricant can be filled in the micropores, the holding force of the lubricant increases, and stable lubrication performance can be exhibited. Also, a relatively hard lubricant can be filled in the micropores.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the rolling and sliding parts according to the present invention and a method for manufacturing the same will be described in detail.
[0017]
A rolling and sliding component according to the present invention is a rolling and sliding component having a rolling surface and a sliding surface, and is made of steel containing 0.2% by weight or more of C, and the rolling and sliding surface remove carbides. A plurality of holes formed as described above are provided, and these holes are filled with a lubricant.
[0018]
The reason why the C content in the steel forming the rolling and sliding parts is limited to 0.2 wt% or more is that if the C content in the steel is 0.2 wt% or more, quenching and tempering or carburizing and quenching are performed. This is because the structure of the steel becomes a mixture of martensite, austenite and carbide by the quenching and tempering, and the strength becomes higher than that of the steel having the ferrite structure. In addition, carbides are present in the steel in a substantially uniform and independent state, and rolling is performed by removing the carbides, and the holes formed in the sliding surface are also independent of each other and rolling so as not to be too deep. It is necessary that the C content of the sliding surface be 0.8 wt% or more. For that purpose, carburizing treatment is performed using steel having a C content of 0.2 wt% or more and less than 0.8 wt%. Is preferred. This is because such steel can easily precipitate carbides of any size and amount by changing the conditions of the carburizing treatment. In addition, when steel having a C content of 0.8 wt% or more is used, carburizing is not essential, and when carburizing is not performed, spheroidizing annealing is preferably performed. As such steels, bearing steels such as high carbon chromium bearing steel and case hardened steel are mainly used. In the case of high carbon chromium bearing steel, material cost is reduced because it is widely used for bearings. Among the high carbon chromium bearing steels, JIS SUJ2 is particularly preferable because it is mass-produced.
[0019]
Further, it is preferable that the hole diameter of the holes is 1 to 3 μm and the area ratio is also 10 to 50%. If the pore diameter is less than 1 μm, it is difficult to fill the lubricant into the pores even if the lubricant is pressurized and impregnated, and if it exceeds 3 μm, the vibration during use increases. If the area ratio is less than 10%, the lubricating effect is insufficient, and if it exceeds 50%, the strength is reduced.
[0020]
Further, as the lubricant, nylon 11 and nylon 12 (both having a melting point of 180 ° C.), polyethylene (with a melting point of 130 ° C.), polypropylene (with a melting point of 150 ° C.) and the like are used. In addition, a mixture of these resins with MoS ₂ or the like generally used as a solid lubricant may be used. The amount of the solid lubricant in the mixture of the resin and the solid lubricant is preferably 5 to 40% by weight based on the entire mixture. The reason for setting the amount of the solid lubricant to 5 to 40% by weight is that if the amount is less than 5% by weight, the effect of improving the lubricity is small, and if it exceeds 40% by weight, the lubricant is difficult to be uniformly mixed with the resin.
[0021]
The method for producing a rolling and sliding component according to the present invention is a method for producing a rolling and sliding component having a sliding surface, wherein the rolling and sliding component is formed into a predetermined shape from steel containing 0.2% by weight or more of C. After rolling, the carbide is substantially uniformly deposited on the sliding surface by subjecting the component material to carburizing treatment, a plurality of holes are formed by electrolytically polishing the surface to remove the carbide, and then forming the plurality of holes. The inside is filled with a lubricant.
[0022]
The reason for limiting the C content in the steel forming the component material is as described above.
As such steels, bearing steels such as high carbon chromium bearing steel and case hardened steel are mainly used. In the case of high carbon chromium bearing steel, material cost is reduced because it is widely used for bearings. Among the high carbon chromium bearing steels, JIS SUJ2 is particularly preferable because it is mass-produced.
[0023]
In the production method according to the present invention, the carburizing treatment is performed by heating at 840 to 870 ° C. for 3 hours or more in a carburizing atmosphere having a carbon potential of 1.2% or more, for example. After this carburizing treatment, the steel is rapidly cooled.
[0024]
In the carburizing treatment, the carbon potential is set to 1.2% or more. If the carbon potential is less than 1.2%, the bearing steel having a carbon content of about 1 wt% is hardly carburized, and the area ratio of the carbide is reduced. May not be as desired, and the carbide may not be made finer, and the pore diameter and area ratio of the holes formed by removing the carbide may not be as desired. Because there is. This carbon potential is preferably set to 1.2 to 1.4%. When the carbon potential exceeds 1.4%, there is a problem that a large amount of soot is generated.
[0025]
The reason why the carburizing treatment temperature is set at 840 to 870 ° C. is that if the carburizing temperature is lower than the lower limit, the necessary carburizing as described in the case of the carbon potential cannot be performed. This is because the crystal grain size of the surface layer portion becomes excessively large, the pores formed by precipitation of giant carbides and removal of the carbides become large, and the strength decreases.
[0026]
The reason why the treatment time of the carburizing treatment is set to 3 hours or more is that, when the treatment time is less than 3 hours, general rolling, rolling of sliding parts, and carburizing depth required for strengthening the surface layer portion on the sliding surface cannot be obtained. It is. The surface layer generally has a range from the surface to a depth of about 0.5 mm. The heating time is preferably set to 3.5 to 5 hours. If the heating time exceeds 5 hours, the heat treatment cost becomes high, and the carbides become large.
[0027]
In the production method according to the present invention, the electropolishing for removing carbides is preferably performed using an aqueous solution of oxalic acid of 5 to 15% by weight as an electrolytic solution at 1 to 6 V for 30 to 60 minutes using the component material as an anode. When electrolytic polishing is performed under such conditions, carbides can be preferentially removed by etching.
[0028]
In the manufacturing method according to the present invention, the filling of the lubricant into the holes is preferably performed by impregnating the holes with the molten lubricant under pressure.
[0029]
Hereinafter, embodiments of the present invention will be described.
[0030]
Example 1
A sliding component material having a sliding surface and a rolling component material having a rolling surface were formed using JIS SUJ2. Then, the sliding part material and the rolling part material are carburized by heating at 850 ° C. for 3 hours in an atmosphere having a carbon potential of 1.3%, then oil-cooled to 80 ° C., and further cooled to 160 ° C. for 2 hours. Tempering treatment for heating for an hour was performed.
[0031]
Then, the sliding component material and the rolling component material are electrolytically polished in a 10 wt% oxalic acid aqueous solution at 5 V for 60 minutes, and the carbide on the sliding surface and the rolling surface is preferentially melted and removed to remove the sliding surface and the rolling surface. Were formed with a plurality of holes. The hole diameter of the holes was 3 μm, and the area ratio of the holes was 20%.
[0032]
Thereafter, nylon 11 heated and melted at 200 ° C. was impregnated with pressure of 15 MPa into the holes of the sliding surface of the sliding component material and the rolling surface of the rolling component material. Thus, sliding parts and rolling parts were manufactured.
[0033]
Example 2
The steps from forming a sliding component material having a sliding surface and a rolling component material having a rolling surface using JIS SUJ2 to forming a plurality of holes in the sliding surface and the rolling surface are described in the first embodiment. Is the same as The hole diameter of the holes was 3 μm, and the area ratio of the holes was 25%.
[0034]
Thereafter, a mixture of polyethylene and MoS ₂ (the content of MoS _{2 in} the mixture is 30 wt%) is heated to 150 ° C. and kneaded, and the kneaded material is used as the sliding surface of the sliding component material and the rolling component material. Was impregnated under pressure at a pressure of 15 MPa. Thus, sliding parts and rolling parts were manufactured.
[0035]
The strength of the sliding parts and the rolling parts manufactured according to Examples 1 and 2 was higher than that of the above-described conventional parts. Further, the sliding surfaces of these sliding components have sufficient sliding performance (for example, self-lubricating performance). In addition, the rolling surface of the rolling component has sufficient self-lubricating performance, and has a strength that can be applied to a bearing ring or a rolling element of a rolling bearing.

Claims (6)

Rolling, rolling and sliding parts having a sliding surface,
A plurality of holes formed by removing carbides are provided on the rolling and sliding surface, the rolling being made of steel containing 0.2 wt% or more of C and filled with a lubricant in these holes, Sliding parts. The rolling and sliding component according to claim 1, wherein the carbide is formed by subjecting the steel to a carburizing treatment. 3. The rolling / sliding part according to claim 1, wherein the hole has a diameter of 1 to 3 [mu] m and an area ratio of 10 to 50%. Rolling, rolling having a sliding surface, a method of manufacturing a sliding component,
Carbide is applied to a component material formed into a predetermined shape with steel containing 0.2% by weight or more of C to deposit the carbide substantially uniformly on the rolling and sliding surfaces, and then the surface is electrolytically polished. Forming a plurality of holes by removing carbides, and then filling the holes with a lubricant. 5. The method according to claim 4, wherein an oxalic acid aqueous solution is used as the electrolytic solution for the electropolishing. 6. The method for manufacturing a rolling and bearing part according to claim 4, wherein the hole is filled with a lubricant by impregnating the hole with a molten lubricant.