JPH1151066A - Roller bearing filled with lubricant contained polymer and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a smooth rotation irrespective of kinds of lublicant contained polymer to be filled by forming coating of solid lubricant at least on the inner circumferential surface of an outer ring and the outer circumferential surface of an inner ring and the surface of rolling bodies. SOLUTION: A ball bearing 1 is assembled in its bearing by a conventional method, then, after degreasing and washing steps are performed, coating 5 composed of solid lublicant is formed on the inner circumferential surface of an outer ring 2, the outer circumferential surface of an inner ring 3, and the surface of a ball 4, and lublicant contained polymer 6 is filled in a space defined by the rings 2, 3 and the ball 4. As the solid lublicant polytetrafluoroethylene, graphite fluoride, or the like is for example used, through there is no special limitation to the selection while as the lublicant contained polymer 6 those composed of thermoplastic resin such as polyethylene, grease and lublicant are for example used, through there is no special limitation to the selection. With this constitution, the outer ring 2, the inner ring 3 and the ball 4 are not in contact with each other, and coating 5 prevents the intrusion of worn powder of lublicant polymer 6 into the gap therebetween, which worn powder is gradually separated by one rotation of the ball bearing 1 to contribut lublication. Accordingly, the smooth ball rotation is ensured with low torque over a long period of time from the initial stage of operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing filled with a lubricant-containing polymer and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, a space between an outer ring, an inner ring, and a rolling element of a rolling bearing is filled with lubricating oil or grease for imparting lubricity. However, since these lubricating oils and greases are liquid or semi-solid substances, they are always sealed with a seal plate or the like in order to prevent them from scattering or fluidizing during rotation of the bearing. For this reason, it was difficult to use these lubricants and grease for small special bearings.

[0003] Therefore, it has been proposed to fill a space between the outer ring, inner ring and rolling elements of a bearing with a polymer containing a lubricant. For example, Japanese Patent Publication No. 63-23239 discloses that grease and polyethylene are used. It is disclosed that a lubricant-containing polymer (plastic grease) is filled in a space formed by an outer ring, an inner ring, and a rolling element of a bearing.
In this lubricant-containing polymer-filled rolling bearing, the lubricant-containing polymer gradually releases grease, which is a lubricating component taken in with the rotation of the bearing, to maintain long-term lubrication. However, in this lubricant-containing polymer-filled rolling bearing, particularly when the lubricant-containing polymer is filled so as to fill the space between the outer ring and the inner ring except for the space occupied by the rolling elements, the lubricant-containing polymer is filled with the lubricant-containing polymer. The rotation of the rolling elements is hindered, and the abrasion powder of the lubricant-containing polymer generated with the rotation of the bearings enters the gaps between the rolling elements and the inner and outer rings, causing a so-called biting phenomenon, and the entire bearing vibrates. In some cases, the function as a bearing was greatly reduced. In addition, the temperature of the bearing may increase accordingly.

In order to solve such a problem, Japanese Patent Application Laid-Open No. H8-31652 discloses a method of forming a lubricant-containing polymer by forming a coating of a lubricant-containing polymer between a cage and a rolling element. To avoid direct contact with the rolling elements.

[0005]

However, the following problems also exist in the rolling bearing in which the coating of the lubricant component of the lubricant-containing polymer is formed. That is, a lubricant-containing polymer-filled rolling bearing is usually obtained by filling a lubricant-containing polymer into a space formed by an outer ring, an inner ring, and a rolling element, and solidifying the space. When solidifying the polymer, it is necessary to melt the unsintered lubricant-containing polymer to a temperature equal to or higher than the melting point of the thermoplastic resin (eg, polyethylene) constituting the lubricant-containing polymer. However, at the time of this melting, the resin and the lubricant are in a state of being dissolved, and the resin is in a state where other components are most easily taken in. Therefore, in such a state, the lubricating components formed on the surfaces of the rolling elements and the like are also taken into the molten resin, and the possibility that the lubricant-containing polymer comes into contact with the rolling elements and solidifies increases. As a result, the rotation of the rolling elements is restricted, and the effect of reducing the torque by the coating of the lubricating component may not be sufficiently exhibited.

Accordingly, an object of the present invention is to solve the above problems, that is, to provide a lubricant-containing polymer-filled rolling bearing capable of maintaining smooth rotation regardless of the type of the lubricant-containing polymer, and It is an object of the present invention to provide a manufacturing method thereof.

[0007]

In order to achieve the above object, the present invention relates to a rolling bearing comprising a space formed by an outer ring, an inner ring and a rolling element filled with a lubricant-containing polymer. At least the inner peripheral surface of the outer ring of the bearing,
A solid lubricant film is formed on the outer peripheral surface of the inner ring and the surface of the rolling element. Further, in order to achieve the same object, the present invention, after assembling the rolling bearing, at least the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring and the surface of the rolling element to form a solid lubricant film, then the outer ring, A space formed by the inner race and the rolling elements is filled with a lubricant-containing polymer and solidified.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a main part showing a ball bearing which is an embodiment of a lubricant-containing polymer-filled rolling bearing according to the present invention. As shown in the drawing, the ball bearing 1 has a coating 5 made of a solid lubricant formed on the inner peripheral surface of the outer ring 2, the outer peripheral surface of the inner ring 3, and the surface of the ball 4 as a rolling element.
Further, a space formed by the outer ring 2, the inner ring 3 and the balls 4 on which the solid lubricant film 5 is formed is filled with a lubricant-containing polymer 6. Therefore, the lubricant-containing polymer 6 is
The presence of the solid lubricant film 5 prevents direct contact with the outer ring 2, the inner ring 3, and the balls 4, and does not hinder the rotation of the balls 4 and the like. Further, since the solid lubricant film 5 is also formed in the gaps between the ball 4 and the outer ring 2 and the inner ring 3, it is possible to prevent wear powder of the lubricant polymer 6 from entering these gaps. Further, the solid lubricant film 5 is gradually peeled off with the rotation of the ball bearing 1 and contributes to lubrication, thereby improving the lubricity particularly in the early stage of operation. At this time, even after the solid lubricant film 5 is peeled off, a gap corresponding to the initial thickness of the solid lubricant film 5 is maintained between the lubricant-containing polymer 6 and the constituent parts of the ball bearing 1. In addition, the lubricant-containing polymer 6 does not directly contact the constituent parts of the ball bearing 1. Further, the lubricant-containing polymer 6 gradually releases a lubricating component taken in with the rotation of the ball bearing 1 to maintain lubrication for a long time. As described above, since the solid lubricant film 5 is interposed between the lubricant-containing polymer 6 and the constituent parts of the ball bearing 1, the ball bearing 1 performs low-torque and smooth rotation over a long period of time from the initial operation thereof. Can be made.

The thickness of the solid lubricant film 5 is 0.1 μm to
It is 100 μm, preferably 0.1 μm to 30 μm.
When the thickness of the solid lubricant film 5 is less than 0.1 μm, the effect of preventing the lubricant-containing polymer 6 from coming into contact with the outer ring 2, the inner ring 3 and the balls 4, and the lubricating action inherent to the solid lubricant are sufficiently exhibited. do not do. On the other hand, when the film thickness exceeds 100 μm, abrasion powder of the lubricant-containing polymer 6 easily enters the gap.

The solid lubricant that can be used in the present invention is not particularly limited, but may be polytetrafluoroethylene (P
TFE), MoS ₂ , graphite, N-lauroyl L
-There are lysine, h-BN, fluorinated graphite and the like. Among them, PTFE and fluorinated graphite whose oil repellency is increased by forming a film are particularly preferable. In addition, these solid lubricants can be used at the time of film formation, such as water, xylene, mineral spirit, isopropyl alcohol, toluene, butyl acetate, methanol, ethylene glycol, and low boiling point perfluorocarbon (specifically, perfluoropentane, perfluorohexane, etc.). ) Or the like dispersed in a dispersion medium.
In consideration of the easiness of film formation, a dispersion medium having a boiling point of 70 ° C. or less is preferable as the dispersion medium. Specific examples of the solid lubricant dispersion include PTFE dispersion KD series of Kitamura Co., Ltd., h-BN (+ organic binder) dispersion-whity series of ODEC Co., Ltd., and Nippon Lubricant Co., Ltd. WS ₂ (+ acrylic organic integrating agent) dispersion liquid Tanmic Bond-A and the like.

The lubricant-containing polymer is not particularly limited, and specific examples thereof include those comprising a thermoplastic resin such as polyethylene and a grease / lubricating oil, and include diallyl phthalate, polyurethane, polynorbornene and the like. Those that cure or crosslink with heat consisting of grease and lubricating oil can also be used.

The above-mentioned ball bearing 1 comprises a process of assembling a bearing by a usual method, degreased and washed, forming a solid lubricant film 5, and then filling and solidifying a lubricant-containing polymer 6. The solid lubricant film 5 can be formed by immersing the ball bearing 1 in a suspension in which the above-described solid lubricant is dispersed in the above-described dispersion medium, or by applying the suspension to the inner peripheral surface of the outer ring 2,
After spraying the outer peripheral surface of the inner ring 3 and the surface of the ball 4, the dispersion medium of the suspension is evaporated. At this time, the concentration of the suspension, the average particle diameter of the solid lubricant, and the immersion or spraying time are adjusted so that the thickness of the solid lubricant film 5 becomes the above-mentioned film thickness.

After the solid lubricant film 5 is formed, a gel or paste-like lubricant-containing polymer 6 obtained by kneading the above-mentioned resin and a lubricating component is coated with the outer ring 2, inner ring 3 and ball 4 of the ball bearing 1. Is filled in the space, and then the whole ball bearing 1 is heated to solidify the polymer in the space and to be held in the ball bearing 1. At this time, the temperature, heating time, and the like differ depending on the type of the polymer, and are appropriately selected. The method of filling the lubricant-containing polymer 6 is not particularly limited, but for example, an injection molding machine described in JP-A-8-309793 can be suitably used. Thereafter, the ball bearing is naturally cooled and filled with the lubricant-containing polymer.

The lubricant-containing polymer-filled rolling bearing of the present invention can be applied not only to the ball bearing 1 shown in FIG. 1 but also to a self-aligning roller bearing 11 as shown in FIG. The self-aligning roller bearing 11 has a structure in which the rollers 14 as the rolling elements can be aligned, and accordingly, the entire bearing can be aligned. More specifically, the self-aligning roller bearing 11 includes barrel rollers 14 arranged in two rows between the inner ring 13 and the outer ring 12 and alternately arranged in the radial direction.
Is held by a retainer 17 formed integrally, and a guide wheel 18 for guiding the rollers 14 between the retainer 17 and the inner ring 13 is arranged concentrically with the retainer 17. Further, a solid lubricant film 15 is formed on the outer peripheral surface of the inner ring 13 and the inner peripheral surface of the outer ring 12, the rollers 14 and the surfaces of the guide wheels 18. The gap between the inner end faces of the inner rings 13 and 14 and the gap between the inner end face of the rollers 14 and the guide wheel 18 are filled with a lubricant-containing polymer 16, respectively.

In the above-described self-aligning roller bearing 11, the inner end face of the roller 14 comes into sliding contact with the guide wheel 18, so that the bearing torque increases and the bearing temperature increases. However, in the present invention, since the solid lubricant film 15 is formed on the surfaces of the rollers 14 and the guide wheels 18, the contact resistance is reduced, so that an increase in bearing torque and an increase in bearing temperature can be effectively suppressed. .

[0016]

EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to this embodiment. Example and Comparative Example After the self-aligning roller bearing (call number: 22311) shown in FIG. 2 was degreased and washed, a PTFE suspension [Kitamura Co., Ltd .: KD-400AS (PTFE central particle size: 0.3 μm, PTFE concentration: 10%, dispersion medium: perfluoropentane)], and then air-dried.
A TFE film was formed. The film thickness was 1 to 5 μm. Then, using the following compound as a lubricant-containing polymer, using an injection molding machine for molding an oil-impregnated polymer described in JP-A-8-309793, the internal space of a bearing formed by an outer ring, an inner ring, rollers and guide wheels. Was filled. Lubricant-containing polymer member: high-density polyethylene 20 wt% ultra-high-molecular-weight polyethylene 5 wt% polyethylene wax 5 wt% mineral oil 70 wt% For comparison, PT is used in the above self-aligning roller bearing for comparison.
The above-mentioned lubricant-containing polymer member was filled without forming an FE film.

For each of the spherical roller bearings obtained by the above operation, a rotation test (N = 800 rpm, Fr =
280 kgf) to measure the outer ring outer diameter temperature and the bearing torque. Table 1 shows the results.

[0018]

[Table 1]

As is clear from the results shown in Table 1, in the bearing of the embodiment, since the PTFE coating is formed on the surface of the rolling element, the outer peripheral surface of the inner race and the inner peripheral surface of the outer race, the parts of the bearing and the lubrication are not affected. No direct contact with the agent-containing polymer
It can be seen that the bearing torque is smaller than that of the bearing of the comparative example, so that the temperature rise of the bearing is also kept low. In addition, since the PTFE film is formed on the surface of the guide wheel, the lubrication between the inner end surface of the rolling element and the PTFE film is also stably maintained, which also reduces the bearing torque. It is thought that they are connected.

[0020]

As described above, according to the present invention,
Since the solid lubricant film is formed on each part of the bearing (outer surface of the inner ring, inner surface of the outer ring, the surface of the rolling element, etc.), each part of the bearing is lubricated by the thickness of this film. The lubricating action of the solid lubricant is added at the same time as a gap is formed between the polymer and the agent-containing polymer. Therefore, poor rotation of the bearing due to biting of the wear powder of the lubricant-containing polymer and friction between the lubricant-containing polymer and each part of the bearing are reduced, and a rise in torque and a rise in temperature of the bearing are also minimized. The bearing can keep rotating smoothly with low torque. At the same time, stable lubrication is maintained by the lubricant gradually released from the lubricant-containing polymer. Also,
Even in the manufacturing method, a solid lubricant film can be formed by a simple treatment such as applying a suspension containing a solid lubricant before filling the lubricant-containing polymer and then leaving the suspension, which particularly hinders the work process. It can be manufactured without any.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a principal part showing one embodiment (a ball bearing) of a lubricant-containing polymer-filled rolling bearing according to the present invention.

FIG. 2 is a sectional view of a main part showing another embodiment (a self-aligning roller bearing) of a lubricant-containing polymer-filled rolling bearing according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ball bearing 2 Outer ring 3 Inner ring 4 Ball 5 Solid lubricant containing film 6 Lubricant containing polymer 7 Cage 11 Self-aligning roller bearing 12 Outer ring 13 Inner ring 14 Roller 15 Solid lubricant containing film 16 Lubricant containing polymer 17 Cage 18 Guide wheel

Claims (2)

[Claims] 1. A rolling bearing in which a space formed by an outer ring, an inner ring and a rolling element is filled with a lubricant-containing polymer, wherein at least the inner peripheral surface of the outer ring of the rolling bearing, the outer peripheral surface of the inner ring and the rolling element. A lubricant-containing polymer-filled rolling bearing having a surface formed with a solid lubricant film. 2. After assembling the rolling bearing, a solid lubricant film is formed on at least the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring, and the surface of the rolling element, and then in a space formed by the outer ring, the inner ring, and the rolling element. A method for producing a lubricant-containing polymer-filled rolling bearing, wherein a lubricant-containing polymer is filled into the rolling bearing and solidified.