JP2009191874A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing having excellent heat resistance and hardly degraded in performance with time in spite of having components composed of environmentally compatible resin. <P>SOLUTION: A deep groove ball bearing comprises: an inner ring 11; an outer ring 12; a plurality of balls 13 arranged in a rollable manner between both rings 11, 12; a crown type cage 14 holding a plurality of balls 13 between both rings 11, 12; and a contact type seal 15 interposed between both rings 11, 12, wherein the cage 14 and the seal 15 are composed of a resin material containing a copolymer of biodegradable resin, and aromatic polyester resin using a bio-derived material as a raw material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rolling bearing.

  When the biodegradable resin is left in the soil or the like, it is gradually decomposed into carbon dioxide and water by bacteria. Therefore, a resin product composed of a biodegradable resin is naturally decomposed until it does not retain its original shape even when released into the natural environment, and thus hardly adversely affects the natural environment. Biomass plastic produced from renewable resources such as plants and other biological resources is also attracting attention as a material that is carbon neutral.

These environmentally friendly resins are mainly used as materials for garbage bags, bottle containers, agricultural multi-films, etc., and their usage has been increasing in recent years. Recently, research and development have been activated as materials for machine parts and structural parts, and application to resin seals and resin cages for rolling bearings is also being considered.
Japanese Patent No. 3791439 JP 2005-29752 A JP 2002-89567 A

However, the conventional environmentally friendly resins as described above have the following problems.
(1) The heat resistance is insufficient. Many conventional environment-friendly resins have a melting point of about 100 to 120 ° C., and even those with a high melting point are about 200 ° C. Moreover, even if it has a high melting point, there are many cases where the mechanical properties are greatly reduced at a temperature of about 100 ° C.
(2) In order to improve heat resistance, a non-recyclable resin synthesized from petroleum-based raw materials may be blended, but it is difficult to say that such a resin is carbon neutral.
(3) Since conventional environmentally-friendly resins may be gradually hydrolyzed even by moisture in the air, mechanical properties are likely to deteriorate over time.

For this reason, it is not easy to apply a conventional environment-friendly resin to a material constituting a machine part such as a rolling bearing.
Therefore, the present invention solves the problems of the prior art as described above, and has excellent heat resistance and performance over time despite having a component composed of environmentally friendly resin. It is an object of the present invention to provide a rolling bearing that is unlikely to decrease.

  In order to solve the above problems, the present invention has the following configuration. That is, the rolling bearing according to claim 1 of the present invention includes an inner ring, an outer ring, a plurality of rolling elements that are arranged to freely roll between the inner ring and the outer ring, and the inner ring and the outer ring, In a rolling bearing comprising a rolling element, the cage is made of a resin material containing a mixture or copolymer of a biodegradable resin and an aromatic polyester resin made from a biological material as a raw material. It is characterized by comprising.

  A rolling bearing according to a second aspect of the present invention is formed between an inner ring, an outer ring, a plurality of rolling elements that are freely rollable between the inner ring and the outer ring, and the inner ring and the outer ring. In a rolling bearing provided with a seal that seals the opening of the formed gap, a resin material containing a mixture or copolymer of a biodegradable resin and an aromatic polyester resin made from a biological material as a raw material, A seal is constructed.

Furthermore, the rolling bearing of claim 3 according to the present invention is the rolling bearing of claim 1 or claim 2, wherein the aromatic polyester resin is chlorogenic acids, derivatives of chlorogenic acids, hydrolysates of chlorogenic acids, And a derivative of a hydrolyzate of chlorogenic acids, wherein at least one is polymerized.
Since the aromatic polyester resin has high heat resistance, the aforementioned mixture and copolymer have excellent heat resistance such as high-temperature rigidity. In addition, due to the action of the aromatic polyester resin, the mixture and copolymer described above have moderate biodegradability, so that they are not easily hydrolyzed by moisture in the air, etc., and the mechanical properties deteriorate over time. However, when it is released into the natural environment such as in the soil, it is naturally decomposed and hardly adversely affects the natural environment.

Therefore, the resin material can be suitably used as a material constituting a rolling bearing component that requires excellent heat resistance and mechanical properties. In particular, when the above-mentioned mixture or copolymer has a high melting point of 250 ° C. or higher, the excellent heat resistance required for the rolling bearing can be sufficiently expressed. Very suitable.
The higher the ratio of the aromatic polyester resin in the above-mentioned mixture or copolymer, the higher the heat resistance and the lower the mechanical properties over time. However, since moldability is deteriorated, the ratio (mixing ratio, copolymerization ratio) of the aromatic polyester resin may be appropriately set according to the purpose of use and the molding method.

  Examples of the biodegradable resin include starch resins (starch modified products, etc.), cellulose compounds (cellulose acetate, etc.), polyesters (polycaprolactone, polylactic acid, polybutylene succinate, polyethylene succinate, polybutylene succinate). Adipate copolymer, polybutylene adipate-terephthalate copolymer, etc.), and polyvinyl alcohol.

  In addition, the aromatic polyester resin is a polyester resin that is derived from a living organism such as a plant, and has a polymerizable material having two or more reactive functional groups. Examples of such biological substances include chlorogenic acids, chlorogenic acid derivatives, chlorogenic acid hydrolysates, chlorogenic acid hydrolyzate derivatives, and hydroxycinnamic acid derivatives. Specifically, chlorogenic acids include chlorogenic acid, chlorogenic acids hydrolysates include caffeic acid and quinic acid, and hydroxycinnamic acid derivatives include 4-hydroxycinnamic acid.

The chlorogenic acids in the present invention include chlorogenic acid, isochlorogenic acid, neochlorogenic acid, and cryptochlorogenic acid. Here, chlorogenic acid is 5-caffeoylquinic acid in which caffeic acid is ester-bonded to the 5-position hydroxyl group of quinic acid, and cryptochlorogenic acid is 4 in which caffeic acid is ester-bonded to the 4-position hydroxyl group of quinic acid. -Caffeoylquinic acid, and neochlorogenic acid is 3-caffeoylquinic acid in which caffeic acid is ester-bonded to the hydroxyl group at the 3-position of quinic acid.
In addition, isochlorogenic acid is dicaffeoylquinic acid (for example, 3,4-dicaffeoylquinic acid) in which caffeic acid is ester-bonded to two of the hydroxyl groups at the 3-position, 4-position and 5-position of quinic acid. 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid).

Examples of other chlorogenic acids include ferryl quinic acid (for example, 5-ferryl quinic acid) in which ferulic acid is ester-bonded to one of the hydroxyl groups at the 3-position, 4-position, and 5-position of quinic acid, the 3-position of quinic acid, Examples include ferryl caffeoylquinic acid (for example, 3-ferryl-4-caffeoylquinic acid) in which caffeic acid and ferulic acid are ester-bonded to two of the 4- and 5-position hydroxyl groups.
Examples of chlorogenic acid derivatives include salts and esters of chlorogenic acids.

  The rolling bearing according to the present invention has excellent heat resistance and hardly deteriorates in performance over time despite having a component made of environment-friendly resin.

The structure of the deep groove ball bearing which is one embodiment of the rolling bearing according to the present invention will be described in detail with reference to the longitudinal sectional view of FIG.
The deep groove ball bearing shown in FIG. 1 includes an inner ring 11, an outer ring 12, a plurality of balls (rolling elements) 13 that are arranged to freely roll between the wheels 11, 12, and a plurality of balls between the wheels 11, 12. A crown-shaped cage 14 (see FIG. 2) that holds the balls 13 equally over the circumferential direction of the deep groove ball bearing, and contact-type seals 15 and 15 interposed between the wheels 11 and 12. ing.

  The seal 15 has an annular shape, and an attachment fitting portion 15a (outer peripheral edge portion) for fitting into a seal groove 12a provided on the inner peripheral surface of the outer ring 12, and a lip portion 15b that slides into contact with the outer peripheral surface of the inner ring 11. And a connecting portion 15c that connects the fitting portion 15a and the lip portion 15b. Such a seal 15 is attached to the inner peripheral surface of both end portions of the outer ring 12 and covers and seals the opening of the gap formed between the inner peripheral surface of the outer ring 12 and the outer peripheral surface of the inner ring 11. In addition, entry of foreign matter from the outside and leakage of lubricant (lubricating oil, grease, etc.) from the inside are prevented. The seal 15 may be a non-contact type or a type having a metal or resin cored bar.

  The cage 14 and the seal 15 of such a deep groove ball bearing are obtained by molding a resin material by an injection molding method or the like. This resin material is a copolymer of a biodegradable resin such as polylactic acid and an aromatic polyester resin. However, a mixture of a biodegradable resin and an aromatic polyester resin may be used. The type of the biodegradable resin is not particularly limited, but polyvinyl alcohol, its modified resin, or polylactic acid, which is excellent in biodegradability and moldability and inexpensive, is preferable. The aromatic polyester resin is obtained by polymerizing at least one of chlorogenic acids, derivatives of chlorogenic acids, hydrolysates of chlorogenic acids, and derivatives of hydrolysates of chlorogenic acids, which are biological substances. . Specific examples of this aromatic polyester resin include polycaffeic acid.

  This resin material may be composed only of the copolymer or the mixture, but may be one to which a filler is added in order to improve mechanical properties. As the filler for improving the mechanical properties, fiber reinforcing materials such as glass fiber and carbon fiber are preferable, but light calcium carbonate (crystal form) is considered in view of the adverse effects on the natural environment when released into the natural environment such as soil. Are preferably hydrous aluminum silicate (kaolin, clay), talc, bentonite, fibrous magnesium hydroxide, wollastonite, sepiolite, carbon black, mica, silicon dioxide, diatomaceous earth, and the like.

Furthermore, in a range that does not adversely affect the heat resistance, biodegradability, mechanical properties, etc. of the resin material, and in a range that does not adversely affect the natural environment when the resin material is decomposed and released into the natural environment. If desired, various additives (lubricants, heat stabilizers, antioxidants, thermal conductivity improvers, plasticizers, etc.) and other types of resins may be blended into the resin material as desired.
This resin material has excellent heat resistance, and mechanical properties are unlikely to deteriorate over time during use. Therefore, the above-mentioned deep groove ball bearing, a part of which is composed of the resin material, is sufficient as a rolling bearing. It has a good performance. Even if this deep groove ball bearing is released into the natural environment such as in the soil, the portion made of the resin material is naturally decomposed, so that the adverse effect on the natural environment is small.

  In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. For example, in the present embodiment, both the cage 14 and the seal 15 are made of the resin material, but one may be made of the resin material and the other may be made of a general resin material. Further, only one of the cage 14 and the seal 15 may be provided, and the other may not be provided.

  Furthermore, the inner ring 11, the outer ring 12, and the ball 13 can also be made of the resin material. Since such a deep groove ball bearing is entirely made of the resin material, the whole is naturally decomposed when released into a natural environment such as soil. Therefore, the adverse effect on the natural environment is extremely small. Since such a deep groove ball bearing can be disposed of in a natural environment such as in the soil, disposal after use is easy.

  Furthermore, in the present embodiment, a deep groove ball bearing has been described as an example of a rolling bearing, but the present invention can be applied to various types of rolling bearings. For example, radial type rolling bearings such as angular contact ball bearings, self-aligning ball bearings, cylindrical roller bearings, tapered roller bearings, needle roller bearings, and self-aligning roller bearings, and thrust types such as thrust ball bearings and thrust roller bearings This is a rolling bearing.

〔Example〕
Hereinafter, the present invention will be described in more detail with reference to examples. The following resin materials (Examples 1 to 3 and Comparative Examples 1 and 2) were injection molded to obtain a crown-shaped cage and seal for a deep groove ball bearing having a nominal number 6203. And the test which evaluates the mechanical strength and heat resistance of a resin material was done using this cage.

First, the used resin material will be described.
The resin material of Example 1 is a resin material composed of 30% by mass of a modified resin of polyvinyl alcohol (PVA), 30% by mass of polycaffeic acid, and 40% by mass of poly-4-hydroxycinnamic acid.
The resin material of Example 2 is a resin material composed of 20% by mass of a modified resin of PVA, 40% by mass of polycaffeic acid, and 40% by mass of poly-4-hydroxycinnamic acid.

The resin material of Example 3 is a resin material composed of 20% by mass of polylactic acid, 30% by mass of polycaffeic acid, and 50% by mass of poly-4-hydroxycinnamic acid.
The resin material of Comparative Example 1 is 100% by mass of the modified resin of PVA, and the resin material of Comparative Example 2 is 100% by mass of polylactic acid.
Next, a method for measuring mechanical strength will be described. The tensile strength at break (annular strength) of the crown cage was measured at room temperature. The results are shown in Table 1. In addition, the numerical value of the annular strength in Table 1 is shown as a relative value when the annular strength of the crown-shaped cage of Comparative Example 1 is 1.

Next, a heat resistance evaluation method will be described. After the crown-shaped cage was suspended in a constant temperature bath at a predetermined temperature (60, 70, 80, 90, 100, 110, 120, 130, 140, 150 ° C.) for 1000 hours, the annular strength was measured. Then, the highest temperature among the temperatures at which the strength decrease from the initial annular strength is 20% or less is defined as the heat resistant temperature of the resin material. The results are shown in Table 1.
As can be seen from Table 1, the mechanical strength and heat resistance of the resin materials of Examples 1 to 3 were significantly higher than those of Comparative Examples 1 and 2 which are conventional biodegradable resins.

  Next, a rolling bearing incorporating a crown-shaped cage and seal made of the resin material as described above was prepared, and its durability was evaluated. That is, the above-described crown-shaped cage and seal made of the resin material, SUJ2 made inner ring, outer ring, and rolling element were assembled to obtain a deep groove ball bearing having a nominal number 6203, and the grease composition was sealed in the bearing inner space. This grease composition is a biodegradable grease in which the thickener is lithium soap, the base oil is ester oil, and the blending degree is 250. The amount of the grease composition enclosed was 20% by volume of the bearing internal space. In a normal case, the amount of the grease composition enclosed is about 35% by volume of the volume of the bearing internal space, but is set to 20% by volume for the acceleration test.

The deep groove ball bearing was rotated (inner ring rotation) under the following conditions, and the time until the rotation was hindered due to deformation of the cage or the seal was measured. The results are shown in Table 1. In addition, when a problem did not arise even if it performed a rotation test for 2000 hours, the test was stopped at that time, and it described as 2000 hours in Table 1.
Rotational speed: 12000min ^-1
Radial load: 98N
Axial load: 245N
Atmospheric temperature: 120 ° C
As can be seen from Table 1, the bearings of Examples 1 to 3 were superior in durability compared to Comparative Examples 1 and 2.

It is a longitudinal cross-sectional view which shows the structure of the deep groove ball bearing which is one Embodiment of the rolling bearing which concerns on this invention. It is a perspective view of the crown-shaped cage used for the deep groove ball bearing of FIG.

Explanation of symbols

11 Inner ring 12 Outer ring 13 Ball 14 Cage 15 Seal

Claims (3)

  In a rolling bearing comprising an inner ring, an outer ring, a plurality of rolling elements that are arranged to freely roll between the inner ring and the outer ring, and a cage that holds the rolling element between the inner ring and the outer ring. A rolling bearing characterized in that the cage is made of a resin material containing a mixture or copolymer of a biodegradable resin and an aromatic polyester resin made from a biological material.   Rolling provided with an inner ring, an outer ring, a plurality of rolling elements that are freely rollable between the inner ring and the outer ring, and a seal that seals an opening of a gap formed between the inner ring and the outer ring. 2. A rolling bearing according to claim 1, wherein the seal is made of a resin material containing a mixture or copolymer of a biodegradable resin and an aromatic polyester resin made from a biological material.   The aromatic polyester resin is obtained by polymerizing at least one of chlorogenic acids, derivatives of chlorogenic acids, hydrolysates of chlorogenic acids, and derivatives of hydrolysates of chlorogenic acids. The rolling bearing according to claim 1 or 2.

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