JPH03162588A - Formation of coating film of solid lubricant - Google Patents

Abstract

PURPOSE:To form a thin coating film of a solid lubricant having satisfactory durability and lubricity on the prescribed surface of a member by previously coating spheres with the solid lubricant and shooting the coated spheres to the prescribed surface of the member to be lubricated at a high speed. CONSTITUTION:Metal spheres 1 of <=5mm diameter are rotated in a rotating tumbler 3 and a solid lubricant such as graphite, molybdenum disulfide or tungsten disulfide of about <=5mum average particles size and a binder are fed from a spray 2 to form metal spheres 6 coated with the solid lubricant in 10mum thickness. The spheres 6 are shot to the surface of a member to be lubricated with compressed air 4 at 0.5-50m/sec speed to form a coating film of the solid lubricant on the surface of the member with part of the coating solid lubricant. A thin film having superior lubricity is formed on the surface of a metal or nonmetal member.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a thin solid lubricant film with excellent durability and good lubricity on, for example, the friction surfaces of precision bearings.

Contact surfaces of small materials used in vacuum areas, high temperature areas, corrosive atmospheres, etc. are often difficult to lubricate with conventional lubricants, so a solid lubricant film is formed on the friction surfaces of these parts. It is preferable to do so.

Also, in precision parts, the clearance between the joint surfaces is small, and therefore a thin solid lubricant film is required.

The present invention relates to a method for forming this thin film with excellent lubricity.

[Prior Art] For example, molybdenum disulfide is an excellent solid lubricant, so it is mixed with an organic or inorganic binder, spray-coated, dried or baked to harden, and is used to form a solid lubricant with a thickness of, for example, 3 to 15 μm. A method of forming a chemical film is being used.

Usually in precision bearings, the thickness of the lubricating film is 3
μ■ or less is desirable. However, with the above method, the thickness of the sprayed film varies depending on the particle size of molybdenum disulfide, and also due to variations in the properties of the pretreatment applied to the surface on which the lubricating film is to be formed. However, it is difficult to form a lubricating film that is stable and has good performance.

Sputtering, vapor deposition, and ion plating can produce thin films, but they have weak sticking properties (throwing power), making them difficult to apply to parts with complex shapes, and vacuum treatment is difficult. It is difficult to obtain a stable solid lubricant skin by heating or heat treatment.

The jet coating method is a method in which, for example, fine powder of molybdenum disulfide is sprayed onto a metal surface at high speed using high-pressure air or the like. Molybdenum disulfide, which is sprayed at high speed, is pierced by the energy of collision with the metal surface, forming a thin lubricant film. However, in order to impart high energy to the lightweight, finely powdered molybdenum disulfide with this method, it is necessary to blow at high speed, which requires a large amount of high-pressure air, and the molybdenum disulfide powder is also scattered. , not economical.

[Problems to be Solved by the Invention] The present invention solves the problem by applying a film with a thickness of 1 on the contact surface of a precision bearing, for example.
The present invention discloses a method for forming a thin solid lubricant film of 0 μm or less, for example 1 to 2 μm, and that is economical and has excellent durability and good lubricity.

[Means for Solving the Problems] The present invention involves projecting a spherical body pre-coated with a solid lubricant onto a surface on which a lubricant film is to be formed at high speed. This method forms a solid lubricant film on the surface.

Examples of solid lubricants used in the present invention include graphite, molybdenum disulfide, tungsten disulfide, boron nitride, and PTFE.
However, it is also possible to use d-compound lubricants mixed with these or other solid lubricants.

The spherical bodies used in the present invention are, for example, steel balls with a diameter of 1 mm, but spherical bodies of other sizes can also be used, and if the spherical bodies are made of a hard material with a high specific gravity, stainless steel balls or other materials may be used. It may be a spherical body made of material.

In the present invention, the metal balls are coated with a solid lubricant in advance.

For example, a solid lubricant powder with an average particle size of 5 μm or less is coated on a spherical body using a binder, but as will be described later, a solid lubricant with a large particle size can also be applied to the surface of the spherical body on which a lubricant film is formed by projection. The solid lubricant may be of other particle sizes in order to open its arms upon collision, and in the present invention, the binder holds the spherical bodies in the solid lubricant until the spherical bodies collide with the surface on which the lubricating film is to be formed. Therefore, the type and amount of binder used may be different from those used to form a conventional solid lubricant film. The coating thickness of the solid lubricant is, for example, 3 to 10μ, but other coating thicknesses may be used depending on the insertion of the solid lubricant and the spherical object projection conditions described later.

In the present invention, spherical bodies coated with a solid lubricant are projected at high speed onto the surface on which a lubricating film is to be formed. For example, the projection speed is 5
m/s, but other projection speeds may be used depending on the material forming the lubricating film, the type of solid lubricant, and the size of the spherical body. High-pressure air, other mechanical or electrical means can be used to project the sphere at high velocity. A magnetic method etc. can be used.

When a spherical body collides with a surface forming a lubricant film, part of the solid lubricant coating the spherical body penetrates the surface and forms a solid lubricant film, and the other part of the solid lubricant coats the spherical body. Peel from. The separated solid lubricant and spherical bodies are collected.

By the above method, a thin film of lubricant with excellent lubrication performance is formed on the surface of metal or non-metal. At the same time, the shot peening effect also improves the lubricity of metal and nonmetal surfaces.

[Action] A mass point with mass m and velocity υ collides with energy of 1 no 2 mυ2. In the jet coating method mentioned above, fine powder of solid lubricant is blown onto the metal surface using high-pressure air and pierced into the metal surface, forming a film of solid lubricant. Because of its low velocity, it must be sprayed at extremely high speeds to form a film.

In the present invention, the spherical body coated with solid lubricant is l/2 m
Collision with energy υ2. During a collision, a coating of solid lubricant is sandwiched between the spherical body and the surface forming the lubricating film. This sandwiched coating is driven into the surface forming a lubricating film by the impact energy of the spherical bodies. The mass of the spherical body is much larger than the mass of the solid lubricant fine powder, and therefore the energy of the collision is also much larger. In the present invention, the solid lubricant is driven into the surface on which the lubricant film is to be formed using the large collision energy of the spherical bodies, so it is easier to form the solid lubricant film than with wide jet coating.

In the present invention, the thickness of the solid lubricant film can be accurately adjusted by adjusting the projection conditions of the coated spherical bodies, resulting in a solid lubricant film with excellent performance even if it is thin.6 There is little variation in film thickness.

The solid lubricant film of the present invention does not utilize the bonding force of an organic or inorganic binder, so there is no need to form a base film such as a chemical conversion film on the surface on which the lubricant film is to be formed as a pretreatment, and the material is maintained with high dimensional accuracy, and the performance of the lubricant film is not impaired due to the nature of the pretreatment.

In the solid lubricant film of the present invention, the particle size of the solid lubricant in the film is homogenized by the fold opening caused by the collision of the spherical bodies, resulting in a film with good performance.

In the present invention, a solid lubricant film can be formed even on a member with a complex shape by adjusting the position and direction of projection of the coated spherical body, and the solid lubricant film can be formed on a member with a complex shape. Since no heating is performed, the solid lubricant does not change in quality, and a film with stable lubrication performance is always obtained.

[Example] An example in which the solid lubricant film of the present invention is formed on a JIS, SUJ2 bearing, shaft, and ball will be described.

As a spherical body, the diameter is 1. A 0 mm stainless steel ball was used.

The solid lubricant is molybdenum disulfide with an average particle size of 3 μm.
Using an epoxy resin as a binder, metal spheres were coated to a thickness of 3 μm using the tumbler apparatus shown in FIG.

The coated metal spheres were dried by heating.

The device shown in Figure 2 was used to project the coated metal sphere at a distance of 2m/2m.
30 minutes with a metal ball on the surface where the lubricating film is to be formed.
The amount of projection was "gr/cm".

By this method, a solid lubricant film with a thickness of 2 μm was formed on the surface of the member.

The performance of this solid lubricant film was tested using a pin-on-plate friction tester. The results are shown in FIG. 3 in comparison with Comparative Example 0 (sample material).The test conditions are as follows.

B) Test material Example of the present invention: The solid lubricant film described above was formed on the surface of a JIS, SUJ-2 steel ball having a diameter of 6III1 by the method of the present invention.

Comparative Example 1: A solid lubricant film of molybdenum disulfide was formed on the surface of a steel ball having the same dimensions and material as the inventive example by rubbing. Comparative Example 2: A solid lubricant film of molybdenum disulfide was formed on the surface of a steel ball having the same dimensions and material as the inventive example by spraying with compressed air.

口）Test conditions The above ball was tested without rotation.

Plate: JIS, SPCC material Load: 3kg Trajectory diameter: 31. I13+m Rotational speed: 180 rpm+m As seen in FIG. 3, the life of the test material on which the solid lubricant film of the present invention was formed was significantly extended compared to Comparative Examples 1 and 2.

[Effects of the Invention] According to the present invention, a solid lubricant film having a thickness of 10 μm or less can be formed on the friction surface of a precision member with high dimensional accuracy.

The solid lubricant film formed by this method has excellent durability and lubricity, and the film formation is more economical and simpler than the jet coating method.

[Brief explanation of the drawing]

Fig. 1 shows an example of a tumbler equipped with a solid lubricant coating. Fig. 2 shows an example of a device for projecting a spherical body coated with a solid lubricant. FIG. 3 is a diagram showing an example of the performance of a solid lubricant film. l: Spherical body coated with solid lubricant 2: Solid lubricant spray 3: Rotating tumbler device 4: High pressure air 5: Nozzle 6: Spherical body coated with solid lubricant 7: Projection direction

Claims (2)

[Claims] (1) A method of forming a solid lubricant film on the surface by projecting a spherical body pre-coated with a solid lubricant onto the surface on which the lubricant film is to be formed at high speed. (2) In advance with molybdenum disulfide and tungsten disulfide,
Forming a solid lubricant film on the surface of a steel material by projecting a steel ball coated with a thickness of 10 μm and having a diameter of 5 mm or less onto the surface of the steel material on which the lubricant film is to be formed at a speed of 0.5 to 50 m/s. Method