JP2008190721A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing in which a cage having a proper strength and friendly to the living environments of organism is used. <P>SOLUTION: This rolling bearing uses the cage made of a material formed by adding a filler to a biodegradable resin. The filler is at least one fiber filler selected from glass fiber, metal fiber, polyvinyl alcohol fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, calcium sulfate whisker, and aluminum borate whisker. The cage made of a material formed by adding the filler to the biodegradable resin can have sufficient strength when the filler is added thereto. Therefore, the rolling bearing using the cage can withstand a long period of service. When the rolling bearing is buried in the ground, the cage is decomposed and returned to soil since it has excellent biodegradability even when it is made of a member other than metal and ceramic members. The rolling bearing does not affect the environment even if it is disposed off. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing, and more particularly to a rolling bearing using a cage made of a biodegradable resin.

  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 iron-based materials and resins are 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.

  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.

  When such disposal is performed, the iron-based material hardly generates harmful substances that affect the environment, and gradually loses its shape due to rust. 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.

  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. In order to solve this, Japanese Patent Application No. 11-305507 proposes that at least one of an inner ring, an outer ring, a rolling element, a cage and a seal constituting a rolling bearing is made of a biodegradable material. . However, in the case of a rolling bearing using a biodegradable resin for the cage, conditions that can be used are limited because the cage is deformed due to insufficient strength of the biodegradable resin during high-speed rotation and high temperature use.

  Then, this invention makes it a subject to provide the rolling bearing which has moderate intensity | strength and uses the holder | retainer gentle to the living environment of living organisms.

  This invention solved the said subject by using the cage | basket consisting of the material which added the filler to biodegradable resin.

  By using a material in which a filler is added to a biodegradable resin, functions such as strength can be fully exerted as a cage, and after leaving it for a long time, the member loses its shape and maintains the living environment of the organism. Can do.

  According to this invention, the cage made of a material obtained by adding a filler to a biodegradable resin has sufficient strength due to the addition of the filler. For this reason, the rolling bearing using this cage can withstand long-term use. In addition, when this rolling bearing is buried in the ground, the cage is excellent in biodegradability even if it is other than a member made of metal or ceramic, so it is decomposed and returned to the soil. Therefore, it does not adversely affect the environment. Therefore, the rolling bearing according to the present invention does not adversely affect the environment even when discarded.

  The rolling bearing according to the present invention uses a cage made of a material obtained by adding a filler to a biodegradable resin.

  As shown in FIG. 1, the rolling bearing is formed of an outer ring 1, an inner ring 2, rollers 3 and a cage 4, and the cage 4 has a role of holding the rollers 3.

  Any rolling bearing such as a bearing, a tapered roller bearing, a self-aligning roller bearing, and a needle roller bearing may be used.

  The above-mentioned biodegradable resin refers to a resin that is decomposed by microorganisms in the environment, and a biodegradability test is defined in JIS K6950 and the like. In general, a resin having a biodegradability of 60% or more according to the above test method is treated as a biodegradable resin.

  It does not specifically limit as biodegradable resin used for the said holder | retainer. Examples thereof include poly (α-hydroxy acid), poly (β-hydroxyalkanoate), poly (ω-hydroxyalkanoate), polyalkylene alkanoate and the like.

  Examples of the poly (α-hydroxy acid) include polylactic acid and polyglycolic acid, and examples of the poly (β-hydroxyalkanoate) include a copolymer of hydroxyvaleric acid and hydroxybutyric acid. Examples of the polyalkylene alkanoates include dehydration condensates of 1,4-butanediol and succinic acid (that is, polybutylene succinate), polyethylene terephthalate copolymers such as polyethylene terephthalate-butylene adipate copolymer, and the like. . From the viewpoint of heat resistance, the above polybutylene succinate, polyethylene terephthalate copolymer such as polyethylene terephthalate-butylene adipate copolymer, polyhydroxybutyric acid, or polylactic acid, or a mixture or copolymer thereof is more preferable. .

  The filler can be used without any particular limitation as long as it is well dispersed with respect to the main component biodegradable resin and imparts strength according to the purpose of use. Specific examples of the filler include fiber fillers such as glass fiber, metal fiber, polyvinyl alcohol fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, calcium sulfate whisker, aluminum borate whisker, mica, talc, etc. Can be given.

  The filling amount of the filler with respect to the biodegradable resin is preferably 5 to 40%, more preferably 10 to 40%. This is because the strength is insufficient when the filling amount is less than 5%, and the biodegradability is impaired when the filling amount exceeds 40%.

Examples of the present invention will be described below. In addition, the material used in this Example and the comparative example is described below.
PBS (1): Bionore (Showa Polymer Co., Ltd .: polybutylene succinate # 1020) 70% by weight + Glass fiber (Asahi Glass Co., Ltd .: CS03JA429T) 30% by weight
PBS (2): Bionore (Showa Polymer Co., Ltd .: polybutylene succinate # 1020) 100% by weight
PA66 ... A3HG2 (BASF: PA66 90% by weight + glass fiber (same as above) 10% by weight)
PLA (1): Lacia (Mitsui Chemicals Co., Ltd .: polylactic acid, M-151SQ52) 70% by weight + glass fiber (Asahi Glass Co., Ltd .: CS03JA429T) 30% by weight
PLA (2) ... Lacia (Mitsui Chemicals Co., Ltd .: polylactic acid, M-151SQ52) 100% by weight
B-PET: Biomax (DuPont WUH: a mixture of polyethylene terephthalate copolymer and glass fiber)

(Examples 1-3)
Of the above materials, PBS (1) was mixed with a Henschel mixer, and molding pellets were produced using a kneading extruder. In addition, PLA (1) also produced molding pellets in the same manner as PBS (1). Each of the obtained pellets including B-PET was dried at 80 ° C. for 10 hours, and then subjected to injection molding to form a test piece. And it provided to the following tensile strength test, bearing test, and biodegradability test. The results are shown in Table 1.

(Comparative Examples 1-3)
A test piece was formed in the same manner as in Example 1 except that the above-described PBS (2), PLA (2), and PA66 were used. And it provided to the following tensile strength test, bearing test, and biodegradability test. The results are shown in Table 1.

[Tensile strength test]
A tensile strength test was performed according to JIS standards. That is, using a No. 1 dumbbell test piece, the tensile speed was 10 mm / min, the room temperature and the strength at 80 ° C. were measured.

[Bearing test]
Rolling bearing equivalent to 608 using SUJ2 for inner ring, outer ring and rolling element, six materials described above for cage, biodegradable grease (manufactured by Kyodo Yushi Co., Ltd .: Biotemp PL) for lubricant. (Diameter: 22 mm, inner diameter: 8 mm, width: 7 mm).

  Using this rolling bearing, an endurance test was performed under general conditions (Fa = 3 kgf, rotation speed = 10000 rpm, temperature = 80 ° C.). At that time, when the rotational torque of the bearing reached twice the initial value due to deterioration or deformation of the cage, the test was stopped because it was impossible to rotate. In Table 1, the time until rotation is impossible is also shown.

[Biodegradability test]
Soil degradability was investigated for the rolling bearing cage. In this method, the cage is embedded in soil having a temperature of 35 ° C. and a moisture of 30% (in the ground 10 cm below the surface) for 6 months. Then, the appearance change and weight change after the test period elapsed (resin residual rate (wt%) when the test piece's initial weight is 100) were examined. In addition, the said external appearance was judged on the following reference | standard.
○: Easily collapses ×: No change, difficult to collapse

[result]
As is apparent from Table 1, Examples 1 to 3 have excellent properties that the tensile strength is equivalent to PA66. Furthermore, the test piece after the biodegradation test was in a state where it was deformed by a slight external force enough to be touched with a finger, and when it was taken out from the soil, it was decomposed to such an extent that its shape could not be observed.

  In contrast, Comparative Example 1 showed excellent properties in strength and bearing tests, but was not biodegradable at all. Further, Comparative Example 2 and Comparative Example 3 have sufficient biodegradability but weak strength. In the bearing test, the cage was deformed by high-speed rotation, and compared with Examples 1-3 and Comparative Example 1. The service life was short.

Partial cutaway view showing an example of a rolling bearing

Explanation of symbols

1 Outer ring 2 Inner ring 3 Roller 4 Cage

Claims (5)

  In a life test of # 608 rolling bearing, a rolling bearing using a biodegradable resin cage added with a filler that has a lifetime of 1500 hours or more under the conditions of an axial load of 3 kgf, a rotational speed of 10,000 rpm, and a temperature = 80 ° C. .   The filler is at least one fibrous filler selected from glass fiber, metal fiber, polyvinyl alcohol fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, calcium sulfate whisker, and aluminum borate whisker. Item 10. A rolling bearing according to Item 1.   The rolling bearing according to claim 2, wherein the filler is at least one fibrous filler selected from glass fiber, polyvinyl alcohol fiber, carbon fiber, and potassium titanate whisker.   The rolling bearing according to claim 3, wherein the filler is glass fiber.   The rolling bearing according to any one of claims 1 to 4, wherein an additive amount of the filler is 5 to 40%.

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