JPH06109022A - Formation of solid lubricating film for part using rolling body - Google Patents

Abstract

PURPOSE:To obtain a solid lubricating film which possesses the excellent quality such as durability and can be applied to the mechanical parts such as a rolling bearing, linear bearing, ball screw, and a ball bush, without using the organic solvent, and to permit the film formation at a complicated recessed part, and to obtain a film formation method suitable for mass productivity. CONSTITUTION:A solid lubricating film 6 is formed by spraying the fine particles (a) as covering material from a nozzle 5, together with air, onto the rolling or sliding frictional surface 1a of a treated article 1 which constitutes a mechanical part using a rolling body. Spraying of the fine particles (a) to the rolling surface 1a as rolling frictional surface is carried out by revolving the treated article 1. As a spraying working device, is used a shot peening machine or a sand blasting machine. As the fine particles (a), is used the soft metal such as gold, silver, lead, zinc, tin, and indium or the high polymeric material such as polytetrafluoroethylene(PTFE) and perfloroalcoxy fluorinated resin (PTA).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rolling element parts such as rolling bearings, ball screws, linear bearings and ball bushes, and particularly to rolling element parts used in a vacuum such as semiconductor manufacturing equipment and space equipment. The present invention relates to a solid lubricant film forming method.

[0002]

2. Description of the Related Art Generally, a rolling bearing is designed so that a lubricant such as grease is supplied between the inner and outer races and the rolling elements and between the rolling elements and a cage to cause sliding friction between them. The rolling friction is reduced and the durability of the bearing is improved. However, when the rolling bearing is used in a vacuum, a lubricant having a high vapor pressure such as grease evaporates into the atmosphere and cannot be used.
In addition, when the rolling bearing is used in a highly clean sealed vacuum, the vapor of the lubricant becomes one of the pollution sources of the environment.
The use of fluid lubricants such as grease is avoided.

Therefore, for such a vacuum rolling bearing, one having a solid lubricating coating formed on the friction surface is used. Not only rolling bearings, but also mechanical parts used in vacuum that include rolling elements such as ball screws, a solid lubricating coating is formed on the friction surface due to the same problem. To form a solid lubricating coating,
Generally, a sputtering method or an ion plating method is adopted.

However, in the case of forming a film by sputtering or ion plating, equipment centering on a vacuum container is required, and the processing equipment becomes complicated and expensive.
Further, since the batch processing is performed, a flow adjusting means such as a temporary storage facility is required in the production line of the object to be processed such as the bearing parts which are continuously produced. In addition, the time required for film formation requires vacuum evacuation, cooling, etc. in accordance with the actual processing time, and if all are included, it will be a long time.
Further, the processing amount, shape and size of the object to be processed and the shape of the processing jig are limited by the shape and size of the vacuum container.

As another method for forming a solid lubricating coating,
There is a so-called dipping method using an organic solvent in which a solid lubricating substance is dissolved or dispersed. However, since the organic solvent is used, there is a problem in that the work environment is not good in addition to the need for devising the concentration control and the like.

Therefore, as a method for easily forming a high-quality coating without using an organic solvent, the present applicant tried the following so-called tumbling method. That is, it is a method in which the object to be treated is put into a container together with a chip-shaped or granular coating material, and is rotated or vibrated to form a coating by the collision. The container is made of resin, which is the same material as the chip-shaped material. However, even by this tumbling method, it is desired that the film has further excellent durability quality and mass productivity. Further, in this method, there is a possibility that the objects to be processed may be damaged by the collision of the objects to be processed, and it takes time and labor for the subsequent inspection process.

The tumbling method, the sputtering method and the ion plating method all have a problem that the smaller the bearing is, the more difficult it is to form a coating film on the invading portion such as the rolling surface of the inner diameter surface of the bearing outer ring. .

The object of the present invention is to obtain a high-quality solid lubricating coating without using an organic solvent, to easily form a coating on the invading place, and to make it suitable for mass production. A method for forming a lubricating coating is provided.

[0009]

According to the method for forming a solid lubricating coating of the present invention, a soft metal or polymer is formed on at least a part of the rolling friction surface and the sliding friction surface of a machine part using a rolling element. In this method, one or more fine particles of a material are blown together with air from a nozzle to form a solid lubricating coating. The rolling element may be a ball or a roller. The mechanical component using the rolling element refers to a mechanical component such as a rolling bearing, a linear bearing, a ball screw, a ball bush, etc., in which the rolling element is interposed between the parts that relatively move. The friction surface on which the film is formed may be the surface in contact with the rolling element of the machine part or the surface of the rolling element.

[0010]

According to this method, the accelerated fine particles are sprayed and collide against the surface to be treated, which is the friction surface of the mechanical component, and the collision energy adheres to the surface to be treated to form a film. Since the coating is formed by colliding at high speed in this way, a coating having a strong adhesive force with the underlying metal is formed. Since the fine particles are made of a soft metal or a polymer material, they can be formed into a film by colliding at high speed without the need for an organic solvent. Since the fine particles are sprayed by using a nozzle, it is possible to form a film even in the invaded portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This embodiment is an example applied to the inner ring 1, the outer ring 2, and the rolling elements 3 in the deep groove ball bearing shown in FIG. FIG. 1 shows a method of forming a coating on the inner ring 1. According to this method, the inner race 1 is held and rotated by an appropriate jig (not shown), and the outer raceway rolling surface 1a, which is a rolling friction surface, is rotated.
Then, the fine particles a to be the coating material are blown together with the compressed air from the nozzle 5 of the spraying machine, and the rolling surface 1a is shown in FIG.
Is a method of forming the solid lubricating coating 6 as described above. A commercially available shot peening machine, sandblasting machine, or the like is used as the spraying processing apparatus. The blowing speed is 5 to 10 kg / cm ^{2 for} the pneumatic type and 40 for the centrifugal type.
It is preferably about 70 m / s.

As shown in FIG. 3, in the case of the outer ring 2, while rotating like the inner ring 1, the fine particles a are sprayed from the nozzle 5 onto the rolling surface 2a of the inner diameter surface to form a solid lubricating coating. As shown in FIG. 4, in the case of the spherical rolling element 3, in the spiral V groove 7a in the guide jig 7, while the rolling element 3 is rotating at random, the fine particles a are transferred from the nozzle 5 onto the rolling element surface. Spray.

The fine particles a as the coating material must be a material that can easily form a coating on the metal surface and act as a lubricant, and a soft metal or polymer material is used. Gold, silver, lead, zinc, tin, indium, etc. can be used as the soft metal. As the polymer material, polytetrafluoroethylene (PTFE) and fluororesin such as perfluoroalkoxy fluororesin (PTA) are suitable.
These fine particles may be used alone, or 2
You may mix and use a kind or more. The size of the fine particles is selected according to the shape and size of the object to be treated, but normally a particle size of about 0.5 to 3.0 mm is suitable, and particularly small particles having a size of 1 mm or less are used.

According to this film forming method, the accelerated fine particles a are sprayed onto the inner and outer races 1 and 2 and the rolling element 3 which are objects to be processed and collide with each other. As a result, the coating film 6 (FIG. 1B) is formed. Since the fine particle a is a soft metal or a polymer material,
By colliding at high speed in this way, the coating film 6 is formed without the need for an organic solvent. Further, since the coating film 6 is formed by colliding at high speed, the adhesive force with the base metal is strong,
The film 6 has excellent durability. Since the fine particles a are sprayed by using the nozzle 5, it is possible to easily form the coating film on the inner diameter surface such as the rolling surface 2a of the outer ring 2 that has entered. Further, since it is sprayed, it is excellent in mass productivity and there is no problem of damage due to collision of objects to be processed.

The experimental results will be described. The inner and outer races 1 and 2 and the rolling element 3 in the bearing shown in FIG. 2 were coated with a commercially available shot peening machine by the method described above with reference to FIGS. Particle a has a particle size of about 0.5 mm
PTFE fine particles were used. As a result, all necessary surfaces of the lubricant, that is, the rolling surfaces 1a, 2a of the inner and outer races 1, 2,
Formation of a uniform film was observed on the entire surface of the rolling element 3. As a result of assembling these inner and outer rings 1 and 2 and the rolling element 3 into a bearing, testing the durability in a vacuum, and comparing with the above-mentioned conventional PTFE solid lubricating coating by the tumbling method, the durability was confirmed to be four times or more. Was done.

The above embodiment has been described for the case of being applied to a deep groove ball bearing. However, the present invention applies to various other bearings, linear bearings, ball screws, ball bushes, ball splines, and other parts that move relative to each other. It can be applied to general mechanical parts with rolling elements interposed therebetween. For example, the method for forming the solid lubricating coating can be applied to the rolling contact surface, the roller peripheral surface, which is the rolling friction surface, and the roller end surface, the flange surface, the cage surface, which are the sliding friction surfaces, in the roller bearing with collar.

FIG. 5 shows an example of a linear bearing to which this film forming method is applied. This bearing is the outer ring 2
1, a ball-shaped rolling element 23 in contact with the shaft 22, and a retainer 24. The outer ring 21 has a plurality of ball raceway surfaces 21a along the axial direction on the inner diameter surface, and ball circulation grooves (not shown) continuing to both ends of the ball raceway surface 21a, and balls that circulate the rolling elements 23 in the cage 24. A guide groove 24a is formed. In this linear bearing, the solid lubricating coating is formed on the raceway surface 21a of the outer ring 21, which is a rolling friction surface, the ball circulation groove, the guide groove 24a of the cage 24, the rolling element 23 and the like by the method described above. Although the drawing shows a type in which balls are used as the rolling elements 23, this coating forming method can be similarly applied to a linear bearing in which rollers are used. In this case, a coating may be formed by this method on the roller end surface and the sliding friction surface that contacts the roller end surface.

FIG. 6 shows an example of a ball screw to which this film forming method is applied. This ball screw has a screw shaft 11
, Nut 12, screw shaft 11 and nut 12
And a large number of ball-shaped rolling elements 15 interposed between the screw grooves 13 and 14. The nut 12 is of an external circulation type in which a return tube 16 is provided to circulate the rolling elements 15. In this ball screw, the thread grooves 13, 14 of the screw shaft 11 and the nut 12, which are rolling friction surfaces,
The solid lubricating coating is formed on the inner surface of the return tube 16 by the above method.

As described above, even when applied to a linear bearing or a ball screw, according to the solid lubricant film forming method of the present invention, the above-mentioned film performance improvement, productivity improvement, and other effects can be obtained.

[0020]

The solid lubricant film forming method of the present invention is a method of forming fine particles of a soft metal or a polymer material together with air from a nozzle onto a friction surface of a machine part using a rolling element to form a solid lubricant film. Therefore, it is possible to form a high-quality coating having excellent durability and the like, which is suitable for mass production. Moreover, a film can be formed without using an organic solvent. Furthermore, since spraying is used, there is no risk of scratches due to collisions of the objects to be processed, and since a nozzle is used for spraying, it is possible to easily form a film even in the invaded place.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a process of forming a film on a bearing inner ring when the method of the present invention is applied to a deep groove ball bearing.

FIG. 2 is a partial sectional view of the deep groove ball bearing.

FIG. 3 is an explanatory view showing a process of forming a film on the outer ring of the bearing.

FIG. 4 is an explanatory view showing a process of forming a film on a rolling element of the bearing.

FIG. 5 is a sectional view of an example of a linear bearing to which the method of the present invention is applied.

FIG. 6 is a partially cutaway perspective view of an example of a ball screw to which the method of the present invention is applied.

[Explanation of symbols]

1 ... Inner ring, 1a ... Rolling groove (rolling friction surface), 2 ... Outer ring,
2a ... Rolling surface (rolling friction surface), 3 ... Rolling element, 5 ... Nozzle, 6 ... Solid lubricating coating, a ... Fine particles

Claims (1)

[Claims] 1. A rolling surface and a sliding friction surface of a machine part using a rolling element, at least a part of the friction surface,
A method for forming a solid lubricating coating of a rolling element-using component, which comprises spraying one or more fine particles of a soft metal or a polymeric material together with air from a nozzle to form a solid lubricating coating.