KR101379871B1 - Preparing method of bush bearing - Google Patents

Abstract

The present invention provides a method for producing a bush bearing including a heat treatment and a plating process, a coating process for undercoating, a lubricant coating process on an inner circumferential surface, and an outer diameter polishing process.

Description

Manufacturing method of bush bearing {PREPARING METHOD OF BUSH BEARING}

The present invention relates to a method of manufacturing a bush bearing in which an oil groove or an oil pocket is formed on an inner surface of a cylindrical body portion.

In general, sliding bearings are mainly used in the shaft rotation of industrial machinery or construction machinery, including the shaft and bush bearings. The sliding bearing described above should be excellent in abrasion resistance, corrosion resistance, etc. in consideration of poor special environments such as sand or fine mineral mixtures and seawater due to the characteristics of its use place. Accordingly, the bush bearing is configured to have abrasion resistance and corrosion resistance from harmful substances introduced between the shaft and the bush bearing by using carbon steel that can increase the hardness of the inner and outer diameters through heat treatment.

However, when the hardness of the existing carburized hardened bearings is high, but harmful substances or metal powders that are higher than the surface hardness of carburized hardened bearings such as silica sand, which are sand particles on the friction surface, wear occurs due to the harmful substances Can be.

In addition, when the deterioration of the above-mentioned harmful substances are made, the contact friction surface is damaged by being more adhered to the corresponding site, which greatly reduces the durability, and the structure of the high frequency hardened bearing is composed of martensite structure, which is weak to corrosion resistance. In a working environment with seawater, corrosion resistance is inevitably deteriorated.

An object of the present invention is to provide a method of manufacturing a bush bearing that can improve the maximum load that can be tolerated by stabilizing the microstructure of the internal material.

Moreover, an object of this invention is to provide the manufacturing method of the bush bearing which was excellent in wear resistance in consideration of the surface friction with a counterpart.

In addition, an object of the present invention is to provide a method for producing a bush bearing in which the lubricity is improved to maintain the regular oil lubrication cycle as long as possible, and the surface treatment which can always contain a certain amount of oil is performed.

The present invention provides a method for producing a bush bearing including a heat treatment and a plating process, a coating process for undercoating, a lubricant coating process on an inner circumferential surface, and an outer diameter polishing process.

In the method of manufacturing a bush bearing provided by the present invention, the structure of the bush bearing may be stabilized by heat treatment, and the strength of the bush bearing may be improved by performing a plating process after the heat treatment.

In addition, the manufacturing method of the bush bearing provided by the present invention can perform the coating process for the base coating, thereby improving the adhesion of the solid lubricant, thereby improving the lubricity.

In addition, the method of manufacturing a bush bearing provided by the present invention can prevent the surface from being damaged by friction even when there is a surface friction with the counterpart by coating a fluororesin-based solid lubricant on the inner peripheral surface of the bush bearing.

In addition, the manufacturing method of the bush bearing provided by the present invention can polish the outer diameter of the bearing to solve the dimensional defects, surface roughness defects in the previous process, and remove the contaminants attached.

1 is a flowchart illustrating a manufacturing process of a bush bearing according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the drawings.

1 is a flowchart illustrating a manufacturing process of a bush bearing according to an embodiment of the present invention.

First, a cylindrical body is formed, and a mold machining process S1 of forming an oil groove or an oil pocket on the inner circumference of the body is performed. The body of the bush bearing is machined from chrome molybdenum steel.

After performing the basic mold forming process (S1), the heat treatment and plating process (S2) is performed to stabilize the structure of the bush bearing and to improve the strength of the bush bearing. At this time, the heat treatment may be carburizing, nitriding, high frequency, and nitriding, but nitriding is more preferable. The heat treatment is first annealed to 850 ~ 900 ℃, then quenched to 800 ~ 900 ℃ second, and tempered by air cooling to 150 ~ 200 ℃.

The heat treatment condition is a nitride heat treatment, the thickness of the compound layer is about 15 ~ 60㎛, the surface hardness including the compound layer is about 1000HV. Of course, if the surface hardness of the bushing bearing is excessively strong compared to the surface hardness of the counterpart, the surface of the counterpart may suffer from abrasion. Therefore, it is better to adjust the surface hardness of the counterpart to be similar to or slightly higher than the counterpart hardness of the counterpart. desirable.

When wear resistance is particularly important according to the use environment, the process of performing the plating process and then the heat treatment may exhibit superior characteristics than the nitriding heat treatment. Plating is carried out Ni-P plating, and then the first and second heat treatment. If the usage environment of the bush bearing is required to be higher than wear resistance, it is preferable that the heat treatment is performed after tungsten or ceramic plating instead of Ni-P plating.

Next, the undercoat coating process (S3) is performed. Coating process (S3) is a process for improving that the solid lubricant does not adhere well to the surface of the bush bearing due to the high hardness and high roughness of the surface of the bush bearing. Manganese phosphate is coated to improve lubrication and wear resistance of bush bearings. First, the bush bearings finished up to the heat treatment step (S2) are subjected to pretreatment such as sanding or acid treatment to increase the adhesion of the solid lubricant, followed by preliminary degreasing and main degreasing using an alkaline solution, followed by washing with water. After the surface adjustment process, the phosphate film is applied. The film thickness is applied to about 5㎛ and then washed with water.

Next, a fluororesin-based solid lubricant coating step (S4) is performed on the inner circumferential surface of the bush bearing. Solid lubricant coating process (S4) is performed by degreasing and drying process, applying a solid lubricant and then heat curing treatment. The thickness is preferably about 17 μm, so that a certain amount can be evenly coated. It is desirable for the coating to maintain concentricity without biasing either side of the inner circumferential surface.

Finally, the outer diameter polishing step S5 of the bush bearing is performed. This is a process for correcting problems that may occur in the outer diameter portion during the heat treatment and plating process (S2), undercoat coating process (S3), solid lubricant coating process (S4). During various processes to improve the wear resistance, strength and lubricity of the inner circumferential surface of the bush bearing, the outer diameter may be changed in dimensions, the surface roughness may be deteriorated, and various contaminants may be attached to the outer diameter. This can cause various problems in assembling the bush bearing. In addition, unexpected failures or damages may occur when the bush bearings are used in actual use. External grinding is used to prevent dimensional correction, residual stress, surface roughness, and remove contaminants.

Claims (8)

A shaping process for forming oil grooves or oil pockets in the inner circumference of the body;
Heat treatment and plating process;
Coating film forming process for base coating;
Solid lubricant coating process; And
External diameter polishing step; manufacturing method of the bush bearing comprising a. The method according to claim 1,
The heat treatment is carried out by any one of carburizing, nitriding and high frequency heat treatment. 3. The method of claim 2,
In the nitriding heat treatment, the thickness of the compound layer is 15 to 60 µm, and the surface hardness including the compound layer is 900 to 1100 HV. The method according to claim 1,
Heat treatment is a method of manufacturing a bush bearing, characterized in that the first heat treatment at 850 ~ 900 ℃, quenched at 800 ~ 900 ℃, air-cooled to 150 ~ 200 ℃. The method according to claim 1,
The plating step is a method for producing a bush bearing, characterized in that any one of Ni-P plating, tungsten plating, or ceramic plating is selectively made. The method according to claim 1,
The film forming process for the base coating is subjected to a pretreatment, preliminary degreasing, main degreasing, washing with water, surface adjustment, coating and drying. The method according to claim 1,
The film forming step for coating the base material is a method of manufacturing a bush bearing, characterized in that the film is formed by using a manganese phosphate. The method according to claim 1,
The solid lubricant coating process includes a degreasing process and a drying process, followed by applying a solid lubricant, followed by heat curing.

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