JP3993377B2 - Rolling bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rolling bearing, and more particularly, to a rolling bearing using a biodegradable material.
[0002]
[Prior art]
Examples of the components of the rolling bearing include an inner ring, an outer ring, a rolling element, a cage, a seal, and a lubricant. Of these, bearing steel and ceramic are generally used for the inner ring, outer ring, and rolling elements, and an iron-based material is used for the cage. In addition, an iron-based material, rubber, or the like is used for the seal, and grease or oil is used for the lubricant.
[0003]
Rolling bearings are generally used in many industrial machines as machine parts. When the predetermined period of use ends, the apparatus is often disposed of as industrial waste without removing the rolling bearing. Most of the disposal methods include incineration, ocean disposal, underground disposal, and leaving in the mountains.
[0004]
[Problems to be solved by the invention]
However, when such disposal is performed, the iron-based material hardly generates harmful substances that affect the environment, and gradually rusts and loses its shape. In contrast, resin, rubber, etc. are extremely stable and remain in their original form with almost no decomposition even if left for a long time, such as ocean disposal, underground disposal, or leaving in the mountains. There is.
[0005]
For this reason, when the rolling bearing is left for a long period of time, the iron material portion does not retain its original shape, but the resin or rubber member retains its original shape. Further, when a fluid resin is used as a lubricant or the like, it may flow out of the rolling bearing and harm the biological environment.
[0006]
Then, this invention makes it a subject to provide the rolling bearing which is kind to the living environment of living organisms.
[0007]
[Means for Solving the Problems]
This invention solved the said subject by comprising at least one among the inner ring | wheel, outer ring | wheel, rolling element, seal | sticker, and holder | retainer which comprise a rolling bearing from a biodegradable material.
[0008]
By using the biodegradable material, the member loses its shape after being left for a long time, and the living environment of the living organism can be maintained.
[0009]
Further, when a biodegradable lubricant is used as the lubricant, the lubricant can be prevented from flowing out into the ground or the sea, and the living environment of the organism can be maintained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0011]
In a rolling bearing such as a ball bearing according to the present invention, at least one of an inner ring, an outer ring, a rolling element, a seal, and a cage is made of a biodegradable material. Of the above-described components, it is preferable that the inner ring, the outer ring, and the rolling element are made of steel or ceramic, and at least one of the seal or the cage is made of a biodegradable material.
[0012]
In addition, a biodegradable material can be used as a lubricant or grease used for lubricating the rolling bearing.
[0013]
Examples of such biodegradable materials include biodegradable resins, biodegradable lubricating oils, biodegradable greases, and the like.
[0014]
The biodegradable resin is a resin that is decomposed by microorganisms in the environment, and the degree of biodegradation is defined in JIS K6950 and the like. Generally, a resin having a biodegradation rate of 60% or more according to this test method is treated as a biodegradable resin. For example, an ester polymer of a polycarboxylic acid such as polyhydroxycarboxylic acid or polyalkylenealkanoate and a polyol. Polyesteramide, starch-modified resin, cellulose compound and the like.
[0015]
The polyhydroxycarboxylic acid is a polymer using hydroxycarboxylic acid as a raw material monomer, and is a homopolymer of hydroxycarboxylic acid such as poly (α-hydroxycarboxylic acid), poly (β-hydroxyalkanoate), poly ( Examples thereof include copolymers of plural kinds of hydroxycarboxylic acids such as ω-hydroxyalkanoate).
[0016]
Examples of the hydroxycarboxylic acid include glycolic acid, D-lactic acid, L-lactic acid, DL-lactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3- Examples thereof include aliphatic hydroxycarboxylic acids such as dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid and 2-hydroxyvaleric acid.
[0017]
Examples of the polycarboxylic acid include succinic acid, valeric acid, terephthalic acid and the like. Examples of the polyol include ethylene glycol and 1,4-butanediol. Examples of the ester polymer of polycarboxylic acid and polyol include polybutylene succinate, polybutylene succinate-adipate copolymer, polyethylene succinate, polyethylene terephthalate-butylene adipate copolymer, and the like. Examples thereof include polymers.
[0018]
Examples of the cellulose compound include cellulose acetate.
[0019]
Among the above, the inner ring, the outer ring, and the rolling element are preferably made of steel from the viewpoint of strength. Moreover, as said biodegradable resin used for a holder | retainer and a seal | sticker, a sliding characteristic, moderate softness | flexibility, ie, it is not fragile with respect to an impact, strength in practical temperature (room temperature-80 degreeC). In view of stability, polybutylene succinate, a mixture or copolymer of polybutylene succinate and polylactic acid, polyethylene terephthalate copolymer such as polyethylene terephthalate-butylene adipate copolymer, polyhydroxybutyric acid, cellulose acetate Etc. are preferably used.
[0020]
When using a biodegradable material for the seal, the biodegradable material includes the above biodegradable resin, natural rubber, synthetic rubber such as aliphatic polyester urethane, biodegradable thermoplastic elastomer, aliphatic Examples thereof include polyester resins. Among these, polybutylene succinate, a mixture or copolymer of polybutylene succinate and polylactic acid, polyethylene terephthalate copolymer such as polyethylene terephthalate-butylene adipate copolymer, polyhydroxybutyric acid, cellulose acetate, etc. are used. Is preferred.
[0021]
The biodegradable lubricant preferably has a biodegradability rate of 60% or more. This is because if the biodegradation rate is less than 60%, the biodegradability of the lubricating oil is lowered and the degradation in the environment may be insufficient.
[0022]
The biodegradation rate is an index for measuring biodegradability, and refers to a value measured according to the OECD 301 method (modified MITI method). This OECD 301 method is a method described in the “Chemical Test Guidelines” of the Organization for Economic Cooperation and Development (OECD).
[0023]
Examples of the biodegradable lubricating oil having a biodegradation rate of 60% or more include vegetable oils and biodegradable synthetic ester oils. Specific examples of this vegetable oil include rapeseed oil, castor oil, rice bran oil, soybean oil, polymerized castor oil, and the like.
[0024]
In addition, as the biodegradable synthetic ester oil, a diester oil obtained from a reaction between a dibasic acid and a branched alcohol, an aromatic ester oil obtained from a reaction between an aromatic tribasic acid and a branched alcohol, a polyhydric alcohol, Examples include polyol ester oils obtained from the reaction of monobasic acids and having a biodegradation rate of 60% or more.
[0025]
Specific examples of the diester oil include dioctyl adipate (DOA), diisobutyl adipate (DIB), dibutyl adipate (DBA), dioctyl azelate (DOZ), dibutyl sebacate (DBS), dioctyl sebacate (DOS) and the like. It is done. Specific examples of the aromatic ester oil include trioctyl trimellitate (TOTM), tridecyl trimellitate, tetraoctyl pyromellitate and the like.
[0026]
Examples of the polyhydric alcohol constituting the polyol ester oil include trimethylolethane (TME), trimethylolpropane (TMP), pentaerythritol (PE), dipentaneerythritol (DPE), neopentyl glycol (NPG), 2 -Methyl-2-propyl-1,3-propanediol (MPPD) and the like. The monobasic acid constituting the polyol ester oil mainly includes monovalent fatty acids having 4 to 18 carbon atoms. Examples include acetic acid, valeric acid, caproic acid, caprylic acid, enanthic acid, pelargonic acid, Caprylic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, tallow acid, stearic acid, caproleic acid, undecylenic acid, Linderic acid, tuzuic acid, fizeteric acid, myristoleic acid, palmitoleic acid, petrothelic acid, oleic acid, Examples include elaidic acid, asclepic acid, vaccenic acid, sorbic acid, linoleic acid, linolenic acid, sabinic acid, ricinoleic acid and the like. The monobasic acid to be reacted with the polyhydric alcohol may be used alone or in combination.
[0027]
The biodegradable grease, that is, a lubricating grease having biodegradability, is a semi-solid product obtained by increasing the biodegradable lubricant with a thickener, and has a decomposition rate of 60% according to the OECD 301C method. The above is good. Examples of the thickener include various metal soaps, fine silica powder, benton series, and urea compounds. Commercially available biodegradable grease can also be used.
[0028]
【Example】
Examples of the present invention will be described below.
[0029]
( Reference Example 1)
SUJ2 for inner ring, outer ring and rolling element, biodegradable resin for cage and seal (Mitsui Chemicals Co., Ltd .: Lacia M-151, mixture of polybutylene succinate and polylactic acid (mixing ratio 5: 5)), lubricant Using a biodegradable grease (Kyoto Yushi Co., Ltd .: Biotemp PL, base oil: biodegradable synthetic ester oil, thickener: metal soap), a rolling bearing equivalent to 608 (outer diameter: 22 mm, inner diameter: 8 mm, (Width: 7 mm). Using this rolling bearing, an endurance test was performed under general conditions (Fa = 2 kgf, rotation speed = 3600 rpm, temperature = 60 ° C.). As a result, operation for 2000 hours or more was possible.
[0030]
Next, the soil degradability was investigated about the rolling bearing after the said test. In this method, the rolling bearing is embedded in soil having a temperature of 35 ° C. and a moisture content of 30% (in the ground 10 cm below the surface) for 6 months. And it performed by the method of measuring the external appearance change and weight change after progress of a test period.
[0031]
As a result, in the rolling bearing, only the inner ring, the outer ring, and the rolling element of the metal portion were kept in the original shape, the cage and the seal were not kept in the original shape, and the weight of the cage and the seal was reduced by 10%. Furthermore, grease was not seen inside and outside the rolling bearing.
[0032]
( Reference Example 2)
A rolling bearing was produced in the same manner as in Reference Example 1 except that Bionole # 1020 (Polybutylene succinate alone) manufactured by Showa Polymer Co., Ltd. was used as the biodegradable resin used for the cage and seal, and the durability test was performed. Went. As a result, operation for 2000 hours or more was possible.
[0033]
Next, the soil degradability was investigated about the rolling bearing after the said test. In this method, the rolling bearing is embedded in soil having a temperature of 35 ° C. and a moisture content of 30% (in the ground 10 cm below the surface) for 6 months. And it performed by the method of measuring the external appearance change and weight change after progress of a test period.
[0034]
As a result, in the rolling bearing, only the inner ring, the outer ring, and the rolling element of the metal portion were kept in the original shape, the cage and the seal were not kept in the original shape, and the weight of the cage and the seal was reduced by 10%. Furthermore, grease was not seen inside and outside the rolling bearing.
[0035]
(Comparative Example 1)
SUJ2 for the inner ring, outer ring and rolling element, polyamide resin for the cage (manufactured by BASF: Ultramid), nitrile rubber for the seal (manufactured by Nippon Synthetic Rubber: JSR N), and mineral oil grease for the lubricant (manufactured by Showa Shell): Using Albania No. 2, base oil: mineral oil, thickener: metal soap, a rolling bearing equivalent to 608 was produced. Using this rolling bearing, an endurance test was performed under general conditions (Fa = 2 kgf, rotation speed = 3600 rpm, temperature = 60 ° C.). As a result, operation for 2000 hours or more was possible.
[0036]
Next, the soil decomposability of the rolling bearing after the above test was investigated by the above method. As a result, in the rolling bearing, not only the inner ring, the outer ring and the rolling element of the metal part, but also the cage and the seal remained in their original shapes. Further, the cage and the seal were not reduced in weight. Moreover, the grease oozed into the soil and contaminated the atmosphere.
[0037]
(Example 1 )
A rolling bearing is produced in the same manner as in Reference Example 1 except that Biomax WUH (filler-containing polyethylene terephthalate-butylene adipate copolymer) is used as the biodegradable resin used for the cage and the seal. The durability test was conducted. As a result, operation for 2000 hours or more was possible.
[0038]
Next, the soil degradability was investigated about the rolling bearing after the said test. In this method, the rolling bearing is embedded in compost having a temperature of 60 ° C. for 3 weeks. And it performed by the method of measuring the external appearance change and weight change after progress of a test period.
[0039]
As a result, in the rolling bearing, only the inner ring, the outer ring and the rolling element of the metal part were kept in the original shape, the cage and the seal were not kept in the original shape, and the weight of the cage and the seal was reduced by 30%. Furthermore, grease was not seen inside and outside the rolling bearing.
[0040]
【The invention's effect】
According to the present invention, even when the rolling bearing according to the present invention is buried in the ground, members other than the members formed of metal or ceramic are decomposed and returned to the soil, so that the environment is not adversely affected. In addition, by using a biodegradable lubricant, soil contamination by the lubricant can be prevented. For this reason, according to the present invention, it is possible to provide an environmentally friendly rolling bearing that does not adversely affect the environment even when discarded.

Claims (4)

A rolling bearing in which an inner ring, an outer ring and a rolling element are made of steel, and a seal and a cage are made of a polyethylene terephthalate-butylene adipate copolymer . The rolling bearing according to claim 1, wherein a biodegradable lubricant is used as the lubricant. The rolling bearing according to claim 2 , wherein the lubricant is a biodegradable grease using a biodegradable synthetic ester oil as a base oil and a metal soap as a thickener. The rolling bearing according to claim 2 , wherein the lubricant is a biodegradable grease using vegetable oil as a base oil and metal soap as a thickener.