JP2004231881A - Liquid polymer lubricant, rolling bearing and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing produced by using a liquid polymer lubricant which can secure a homogeneous dispersibility of a lubricant without heating at a higher temperature and moreover can enclose a solid polymer lubricant compactly in a space formed between a bearing ring and a rolling element. <P>SOLUTION: The rolling bearing comprises an inner and outer ring 1, 2, a plurality of a rolling element 3 and a solid polymer lubricant material 4 enclosed between the outer ring 1 and the each rolling element 3. As the solid polymer lubricant 4 is used a material solidified by evaporating the solvent of a liquid polymer lubricant containing a lubricant, a low molecular weight resin whose number average molecular weight is 1,000-50,000 and a solvent. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid polymer lubricant used for manufacturing a solid polymer lubricant constituting a rolling bearing such as a deep groove ball bearing and a self-aligning roller bearing, a rolling bearing manufactured using the same, and a method for manufacturing the same.
[0002]
[Prior art]
BACKGROUND ART In rolling bearings, lubricating oil and grease are generally used to improve lubricity between the raceway surfaces of an inner ring and an outer ring (track ring) and the surface of a ball or a roller (rolling element). However, lubricating oil and grease may be scattered outside the bearing, or foreign matter may be mixed in from the outside of the bearing, resulting in poor contact between the raceway surface and the rolling element surface, causing seizure, etc. is there. For this reason, a solid polymer lubricant in which lubricating oil is dispersed in a resin is sealed in the space formed between the bearing ring and the rolling element, thereby providing a rolling bearing having both lubricity and sealing properties. Development is underway.
[0003]
Among these, for example, ultrahigh molecular weight polyethylene (number average molecular weight: 200,000 or more) and a lubricant are mixed, heated to a temperature higher than the melting temperature of the ultrahigh molecular weight polyethylene (135 ° C or higher), and then solidified by cooling to solid polymer lubrication. Techniques for encapsulating materials have been proposed. Specifically, (1) After injecting a mixture of ultra-high molecular weight polyethylene and a lubricant dispersed in a solvent into a space, the mixture is heated at a temperature equal to or higher than the melting temperature of ultra-high molecular weight polyethylene, and then cooled and solidified. A technique for encapsulation (for example, see Patent Document 1), or a technique for (2) injecting similar components into a gap in a molten state using an injection molding machine, and then cooling and solidifying for encapsulation (for example, see Patent Document 2) Has been proposed.
[0004]
[Patent Document 1]
JP-A-6-50330 (page 2)
[Patent Document 2]
JP-A-2002-212581 (page 2)
[0005]
[Problems to be solved by the invention]
However, in the method (1), it is necessary to heat and melt the ultra-high molecular weight polyethylene at a high temperature in order to uniformly disperse the lubricant, so that the heating cost is high and it is difficult to provide an inexpensive product. was there. Further, the method (2) has a problem that it is difficult to spread the molten resin to every corner of the space formed between the bearing ring and the rolling element, and a gap is formed in the rolling bearing. was there. Further, there is also a problem that it is difficult to apply any of the above methods (1) and (2) to other than metal rolling bearings because it is necessary to manufacture at a high temperature.
[0006]
The present invention has been made in view of such circumstances, and it is possible to ensure uniform dispersion of a lubricant without heating at a high temperature, and further, without any gaps in a space formed between a bearing ring and a rolling element. It is an object of the present invention to provide a liquid polymer lubricant capable of enclosing a solid polymer lubricant, a rolling bearing manufactured using the same, and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
The liquid polymer lubricant of the present invention comprises a lubricant, a resin, and a solvent for dissolving and dispersing the resin, wherein the resin has a number average molecular weight of 1,000 to 50,000. And
[0008]
According to the above configuration, since the low molecular weight resin having a number average molecular weight of 1,000 to 50,000 is used as the resin component, the low molecular weight resin can be uniformly dispersed in the solvent together with the lubricant. . In addition, the liquid polymer lubricant thus uniformly dispersed can be spread to every corner of the space formed between the bearing ring and the rolling element. Therefore, the solid polymer lubricant in which the lubricant is uniformly dispersed can be sealed between the race and the rolling element without any gap. Further, since the solid polymer lubricant can be formed by volatilization of the solvent at a temperature lower than the melting temperature of the conventional ultra-high molecular weight polyethylene, the heating cost can be suppressed, and therefore, an inexpensive rolling bearing can be provided. Furthermore, since high-temperature heating is unnecessary, there is an advantage that the present invention can be applied to a rolling bearing composed of, for example, a resin bearing ring or a rolling element. The reason why the number average molecular weight of the resin is in the range of 1,000 to 50,000 is that if the resin has a high molecular weight exceeding 50,000, it cannot be uniformly dispersed in the solvent. If the molecular weight is less than 2,000, the strength of the solid polymer lubricant becomes insufficient.
[0009]
A rolling bearing according to the present invention includes an inner ring, an outer ring, a plurality of rolling elements disposed so as to freely roll between the inner ring and the outer ring, and a space formed between the inner ring, the outer ring, and each rolling element. And a solid polymer lubricant encapsulated in the liquid polymer lubricant, wherein the solid polymer lubricant solidifies the liquid polymer lubricant by volatilization of a solvent in the liquid polymer lubricant. It is characterized by:
[0010]
According to the above configuration, the solidified polymer lubricant obtained by removing the solvent in the liquid polymer lubricant by volatilization is used as the solid polymer lubricant, so that the raceway surface and the rolling element surface are rotated during rotation of the bearing. The lubricant can be stably supplied in between. In addition to the lubricant being supplied due to wear of the solid polymer lubricant and oozing out of the lubricant during the rotation of the bearing, traces of the solvent volatilization form a path and form a contact between the raceway surface and the rolling element surface. Lubricants can be supplied. Moreover, the solid polymer lubricant can prevent foreign matters from being mixed into the contact portion between the raceway surface and the rolling element surface. Therefore, it has good lubrication and sealing properties, and a long-life rolling bearing can be provided.
[0011]
The method for manufacturing a rolling bearing according to the present invention is a method for manufacturing the above-described rolling bearing, wherein the liquid polymer lubricant described above is injected into a space formed between an inner ring, an outer ring and each rolling element. The solid polymer lubricant encapsulated in the space is formed by heating the solvent above the volatilization temperature of the solvent in the liquid polymer lubricant to volatilize the solvent. According to the above configuration, a rolling bearing having both good lubricity and good sealing can be easily manufactured.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view schematically showing a deep groove ball bearing according to an embodiment of the rolling bearing of the present invention. This deep groove ball bearing includes an outer ring 1, an inner ring 2, and a plurality of (for example, eight) balls 3 as a plurality of rolling elements between the inner and outer rings. A solid polymer lubricant 4 is sealed in a space formed by the outer ring 1, the inner ring 2 and each ball 3.
[0013]
The solid polymer lubricant 4 can be formed using a liquid polymer lubricant containing, for example, low molecular weight polyethylene as a resin, toluene as a solvent, and polyalphaolefin (PAO) as a lubricant. Specifically, first, a low molecular weight polyethylene solution having a solid content of 20% by weight (polyethylene number average molecular weight: 5000, solvent: toluene) and PAO (30 cSt (40 ° C.)) were mixed at a weight ratio of 1: 1. To prepare a liquid polymer lubricant. Then, the liquid polymer lubricant is injected into a space formed by the outer ring 1, the inner ring 2 and the balls 3 (injected in a state where a seal is fitted on one side so as not to leak) to fill the space. Then, the mixture is heated to a temperature (60 to 80 ° C.) at which the solvent in the liquid polymer lubricant easily evaporates. Thereby, the toluene in the liquid polymer lubricant is removed by volatilization and solidified. In addition, you may heat-process at below this temperature. In this case, there is an advantage that when heated in a vacuum, the volatilization of the solvent is promoted. Thus, the solid polymer lubricant 4 can be formed.
[0014]
The deep groove ball bearing according to the present embodiment is formed by the outer ring 1, the inner ring 2, and each ball 3 because the solid polymer lubricant is formed using a liquid polymer lubricant containing low molecular weight polyethylene, toluene, and PAO. The solid polymer lubricant can be sealed to every corner of the space. In addition, since low-molecular-weight polyethylene is used, the PAO is uniformly distributed in the solid polymer lubricant. Therefore, PAO can be stably supplied from the solid polymer lubricant during the rotation of the bearing. Therefore, the contact state between the raceway surfaces of the outer ring 1 and the inner ring 2 and the surface of each ball 3 is good for a long period, and a long-life deep groove ball bearing is obtained. The present inventor has developed a deep groove ball bearing (Example product) enclosing a solid polymer lubricant in which toluene is removed by volatilization using the low molecular weight polyethylene solution and solidified, and an ultra high molecular weight polyethylene (number average molecular weight of 200,000). ) Was compared with a deep groove ball bearing (comparative product) that encapsulated a solid polymer lubricant that was heated and melted, then cooled and solidified. As a result, the product of the working example was longer than the product of the comparative product. Check that the service life was reached.
[0015]
In the above, the case where low molecular weight polyethylene is used as the resin constituting the liquid polymer lubricant has been described, but the number average molecular weight Mn may be in the range of 1,000 to 50,000, preferably 2,000 to 10,000. Any of various resins such as linear and branched resins can be used. Specifically, low molecular weight polypropylene, low molecular weight polyacetal, or the like can be used. These may be used alone or in combination of two or more.
Also, the solvent is not limited to toluene, and can be appropriately selected according to the type of the resin to be dissolved. However, a solvent having high volatility is preferable in consideration of volatilization and removal of the solvent. These may be used alone or in combination of two or more.
Further, the lubricant is not limited to PAO, and a known lubricant such as mineral oil, synthetic lubricating oil, and grease may be used. However, those having low volatility are suitable so that they are not removed by volatilization with the solvent. These may be used alone or in combination of two or more.
Further, the liquid polymer lubricant may be one in which polytetrafluoroethylene (PTFE) powder, which is a solid lubricant, is dispersed. For example, PTFE powder may be dispersed in a solution in which low molecular weight polyethylene is dissolved in a solvent such as toluene. When such a liquid polymer lubricant is used, a solvent such as toluene is volatilized to obtain a solid polymer lubricant which is an eutectoid in which PTFE is mixed with a precipitate of low molecular weight polyethylene.
Further, the present invention is not limited to a deep groove ball bearing, but is applicable to various rolling bearings such as a self-aligning roller bearing. Further, since the solid polymer lubricant can be formed at a temperature lower than the melting temperature of the resin, it can be applied to rolling bearings other than those made of metal (for example, made of resin).
[0016]
【The invention's effect】
As described above, according to the liquid polymer lubricant of the present invention, a solid polymer lubricant in which the lubricant is uniformly dispersed can be produced, and a void portion is formed in the space formed between the raceway and the rolling element. The solid polymer lubricant can be encapsulated without the need. Further, according to the rolling bearing of the present invention, it is possible to stably supply the lubricant to the contact portion between the raceway surface and the rolling element surface during rotation of the bearing, and it is possible to prevent foreign matters from being mixed into the contact portion. , Longer life. Further, according to the method for manufacturing a rolling bearing of the present invention, a rolling bearing having both good lubricity and good sealing properties can be easily manufactured.
[Brief description of the drawings]
FIG. 1 is a sectional view schematically showing a deep groove ball bearing according to an embodiment of a rolling bearing of the present invention.
[Explanation of symbols]
1 inner ring 2 outer ring 3 balls (rolling element)
4 Solid polymer lubricant

Claims (3)

A liquid polymer lubricant comprising a lubricant, a resin, and a solvent for dissolving and dispersing the resin, wherein the resin has a number average molecular weight of 1,000 to 50,000. An inner ring, an outer ring, a plurality of rolling elements rotatably disposed between the inner ring and the outer ring, and solid polymer lubrication sealed in a space formed between the inner ring, the outer ring, and each rolling element. A rolling bearing comprising
A rolling bearing, wherein the solid polymer lubricant is obtained by solidifying the liquid polymer lubricant according to claim 1 by volatilization of a solvent in the liquid polymer lubricant. A method for manufacturing a rolling bearing according to claim 2, wherein the liquid polymer lubricant according to claim 1 is injected into a space formed between an inner ring, an outer ring, and each rolling element, A method for manufacturing a rolling bearing, wherein a solid polymer lubricant encapsulated in the space is formed by heating the solvent in the liquid polymer lubricant to a temperature equal to or higher than a volatilization temperature of the solvent to volatilize the solvent.

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