JP2000346082A - Cage for bearing and rolling bearing using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance of a bearing with retaining flexibility of a cage by providing a component immersion inhibiting layer, being used for the bearing where an oil film running out inhibitor is added in lubrication oil, on a surface side to prevent immersion of components contained in the oil film running out inhibitor into an inner part of the cage for the bearing made from polyamide resin. SOLUTION: A cage 4 is provided by molding out of polyamide resin, and formed of cage pockets 6 for fitting and retaining balls 3 with opening to one end side of an axial direction on several places of an annular parent body 5 at an almost equal interval on the circumference. A ball retaining pawl 8 projecting toward the opening part side of the cage pocket 6 is formed at a tip of a dividing projecting piece 7 remaining between adjoining pockets 6. A recessed part 9 is formed between the ball retaining pawls 8 by providing them on both sides in the circumferential direction on a free end side of each dividing projecting piece 7. The recessed part 9 is a part for reserving lubricating oil immersing during employment or the like. An oil film of the lubricating oil lubricates between a rolling surface of both an inner ring 1 and an outer ring 2 and the ball 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing retainer made of polyamide resin and a rolling bearing using the same.

[0002]

2. Description of the Related Art For example, crown type cages of rolling bearings are made of resin from the viewpoint of weight reduction, and among these resins, polyamide is generally selected in order to hold rolling elements with high flexibility. Has been used.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have developed a technique in which a rolling element rotates at a high speed under a high load on a rolling surface using a lubricating oil mixed with an oil film breakage inhibitor such as phosphorus or sulfur. I was studying how to prevent the oil slick from running out. In the course of the research, it was found that the rolling bearing provided with the cage made of the polyamide resin has a tendency that the cage becomes brittle and easily broken. Thus, the present inventors have conducted intensive research on the cause. As a result, as the temperature rises with the rotation of the rolling bearing, phosphorus or sulfur, which is a component in the oil film breakage preventing agent, enters the polyamide resin and cuts the molecular chain that bonds between the molecules of the polyamide resin. It is possible to determine that the cause is that the cage loses flexibility and becomes brittle and deteriorated even though the cage is made of a polyamide resin, and as a result, it eventually leads to breakage easily. Reached.

Therefore, the present inventors have taken the following measures.
First, instead of a polyamide resin, super engineering plastics (PPS, PE, etc.) may be used as a plastic material having excellent resistance to the oil film breakage inhibitor.
EK, etc.), but cannot be used for a rolling bearing that requires flexibility of the cage. Secondly, it was considered not to add such an oil film breakage preventive agent to the lubricating oil, but this cannot be used because oil film breakage cannot be prevented.

In the present invention, in a bearing cage made of a polyamide resin, the flexibility of the cage is not impaired by the oil film breakage preventive agent in the lubricating oil, thereby contributing to the improvement of the performance of the bearing. It is an object of the present invention to provide a bearing retainer.

[0006]

SUMMARY OF THE INVENTION A bearing retainer of the present invention is used for a bearing in which an oil film breakage preventing agent is added to lubricating oil in a bearing retainer made of a polyamide resin. And a component intrusion prevention layer for preventing the components in the oil film breakage preventing agent from entering the inside of the cage on the surface side.

Preferably, the component intrusion prevention layer is an organic polymer layer.

In the present invention described above, in short, the flexibility, which is a feature of the polyamide resin, can be utilized, and at the same time, the component of the oil film break prevention agent can be prevented from entering the resin by the component intrusion prevention layer. As a result, the above-mentioned disadvantages of embrittlement and breakage are eliminated, and as a result, the performance of a bearing supported by the polyamide resin can be improved by utilizing the flexibility characteristic of the polyamide resin.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 1 is a perspective view of a crown type cage according to an embodiment of the present invention, and FIG. 2 is a developed view showing a part of the cage. FIG. 3 is a perspective view showing a partially cutaway deep groove ball bearing which is an example of a rolling bearing using the cage.
FIG. 4 is a sectional view of each part of the ball bearing of FIG. In this embodiment, the rolling bearing is not limited to a deep groove ball bearing.

In FIGS. 3 and 4, A denotes the entirety of a deep groove type ball bearing. As is well known, this ball bearing A has a number of rolling elements between an inner ring 1 and an outer ring 2 as rolling elements. Ball 3
And a large number of the balls 3 are aligned and held by a crown-shaped retainer 4, so that the circumferential distance between the groups of balls 3 is kept constant.

In FIG. 1 and FIG. 2, a cage 4 is obtained by molding a polyamide resin, and pockets 6 for inserting and holding the balls 3 are provided at several locations on the annular base 5 at substantially equal circumferences. Are formed to open to one end in the axial direction. A ball holding claw 8 that projects toward the opening of the pocket 6 is formed at the tip of the partitioning protrusion 7 remaining between the adjacent pockets 6. In this way, each partitioning projection 7
By providing ball holding claws 8 on both sides in the circumferential direction on the free end side, a concave portion 9 is formed between them. The recess 9 is a portion in which, for example, lubricating oil enters during the use process and is stored.

In the above-mentioned ball bearing A, the rolling property is ensured by lubricating the ball 3 between the rolling surfaces of the inner ring 1 and the outer ring 2 and the oil film by the lubricating oil. The oil film breakage preventive agent such as phosphorus or sulfur described above is mixed between the rolling surface and the ball 3 due to the application of a high load by rotation to prevent the oil film from breaking.

The cage 4 used for such a ball bearing A is made of polyamide because the cage 4 must have flexibility in order to easily insert the ball 3 into the pocket 6 and prevent the ball 3 from coming out. It is made of resin.

[0015] In the above construction, the components of phosphorus and sulfur of the oil film breakage preventing agent mixed in the lubricating oil are:
In order to prevent the resin from deteriorating due to chemical attack such as cutting the molecular chain by invading the polyamide resin constituting the retainer 4, in the present embodiment, the retainer 4 is used. Is characterized by having a component intrusion prevention layer 10 for preventing intrusion of components of the oil film breakage preventive agent on the front surface side.

The formation of the component penetration preventing layer 10 will be described.

On the surface side of the cage 4, the polyamide resin (base material) is coated with silica. One of the silica coatings is a coating treatment with polysilazane. As a specific method of the coating treatment, a polyamide-based resin on the surface of the cage 4 is used as a base material, and this is coated with polysilazane. In this coated state, the cage 4 is fired in the air or steam to convert the polysilazane into silica. As a result, an organic polymer layer, which is a bond of nitrogen and silicon, is formed on the surface of the retainer 4 as the component intrusion prevention layer 10. Note that polysilazane is a polymer composed of Si, N, H or an organic group, and is one of ceramic precursor polymers that are converted into silica (SiO ₂ ) or silicon nitride (Si ₃ O ₄ ) by heating or the like. As an existing method of silica coating, there is a sol-gel method in a wet system, but when polysilazane is used, a film can be made thicker than in the sol-gel method. As described above, polysilazane is a generic name of a polymer having a bond between silicon and nitrogen, and a polymer having all hydrogen side chains is called perhydropolysilazane. This is caused by reacting with ammonia in the presence of dichlorosilane and pyridine (ammonolysis reaction)
It is produced together with the by-product of ammonium chloride. For such polysilazane coating, dipping method,
There are a roll method, a spray method, and a spin coating method. Coating with a brush is also possible. Thus, the component intrusion prevention layer 10 is formed by the silica coating by the conversion of the polysilazane to the silica-based resin. This component intrusion prevention layer 10 prevents phosphorus or sulfur from entering the inside of the cage 4 as a component of the oil film breakage preventing agent in the lubricating oil. The technology of silica coating using such polysilazane is disclosed in “Coatings and Paints”, November 1997, No. 569, issued by Tonen Corporation.

The organic polymer layer thus formed on the surface of the cage 4 functions as a component intrusion prevention layer 10 for preventing intrusion of phosphorus and sulfur which are components of the oil film breakage preventing agent.

By the way, since the polyamide resin has hygroscopicity, a cage using such a resin has a disadvantage that its dimensional change due to moisture absorption becomes large. Therefore, preferably, a metal layer is formed on the component intrusion prevention layer 10,
Most preferably, a soft metal layer such as copper, silver, gold, lead, or tin is formed by means such as vapor deposition to form the non-hygroscopic moisture intrusion prevention layer 11. When the moisture intrusion prevention layer 11 is a soft metal layer, it is preferable in terms of lubrication characteristics.

In this case, the component intrusion prevention layer 10 is formed as a pretreatment of the moisture intrusion prevention layer 11, but if the purpose is only to prevent moisture intrusion, the formation of the component intrusion prevention layer 10 is omitted. Only the moisture intrusion prevention layer 11 may be formed. The formation of the moisture intrusion prevention layer 11 basically prevents the cage 4 from being directly contacted with the external atmosphere. Oxidation resistance, oil resistance and chemical resistance are improved.

[0021]

As described above, according to the present invention, the following effects can be obtained.

According to the bearing retainer of the present invention, in a bearing retainer made of a polyamide resin, the bearing retainer is used for a bearing in which an oil film breakage preventing agent is added to lubricating oil.
In addition, since the component in the oil film break prevention agent has a component intrusion prevention layer for preventing the components in the oil film break prevention agent from entering the inside of the cage, the flexibility of the oil film break prevention agent is not impaired by the components of the oil film break prevention agent. Can improve the performance of the bearing.

According to the bearing retainer of the present invention, since the component intrusion prevention layer is a layer formed by silane bonding treatment on the surface of the retainer, it becomes an amorphous layer and becomes a layer in the oil film breakage preventing agent. Phosphorus, sulfur, etc., which cannot penetrate them, are effectively prevented from penetrating into the inside, so that their flexibility can be further maintained, and the performance of a bearing using the same can be further improved.

According to the third aspect of the present invention, since a moisture intrusion preventing layer for preventing intrusion of moisture into the cage is provided on the intrusion preventing layer, the cage dimensions due to moisture absorption of the polyamide resin are provided. Is preferably suppressed.

In the bearing retainer according to the fourth aspect, since this moisture intrusion prevention layer contains a soft metal, it is preferable in terms of lubrication characteristics of the retainer.

[Brief description of the drawings]

FIG. 1 is a perspective view of a crown type cage according to an embodiment of the present invention.

FIG. 2 is a developed view showing a part of the cage of FIG. 1;

FIG. 3 is a perspective view showing a deep groove type ball bearing as an example of a rolling bearing using the cage of FIG.

FIG. 4 is a sectional view of each part of the ball bearing of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Ball 4 Cage 10 Barrier layer

Claims (5)

[Claims] 1. A bearing cage made of a polyamide resin, which is used for a bearing in which an oil film breakage preventing agent is added to lubricating oil, and wherein the component in the oil film breakage preventing agent is provided on the surface side. A bearing retainer having a component intrusion prevention layer for preventing intrusion into the retainer. 2. The bearing cage according to claim 1, wherein the component intrusion prevention layer is an organic polymer layer. 3. The bearing retainer according to claim 1, further comprising a moisture intrusion prevention layer on the component intrusion prevention layer for preventing intrusion of moisture into the inside of the cage. Retainer. 4. The bearing retainer according to claim 3, wherein said moisture intrusion prevention layer contains a soft metal. 5. A rolling bearing comprising: the bearing retainer according to claim 1; and a rolling element held by the bearing retainer.