JP3757988B2 - Roller bearing cage - Google Patents

Description

【００２３】
○実施例２
ポリオレフィン樹脂として、超高分子量ポリエチレン〔三井石油化学（株）製ミペロンＸＭ２２０〕１０重量％とポリプロピレン〔三井石油化学（株）製ハイポールＢ−２００Ｐ〕６０重量％との混合物を使用し、潤滑油として液温１１０℃のポリα−オレフィン油〔モービル石油化学（株）製ＳＨＦ６１〕とした以外は実施例１と同様にして保持器を作製し、更に実施例１と同様の回転試験に供した。
焼き付け時間及び含油量の測定結果を、第１表に示す。
【００２４】
○実施例３
ポリオレフィン樹脂として、ペレット状のポリメチルペンテン（ガラス繊維３０％含有グレード、ＦＲ−ＴＰＸ Ｔ１３０）〔三井石油化学（株）製〕を使用して実施例１と同様の冠型保持器に射出成形した後、液温１５０℃のジアルキルジフェニルエーテル型合成油〔松村石油研究所（株）製モレスコハイルーブＬＢＸ−１００〕中に浸漬した。
このようにして含浸処理された成形体（保持器）を、実施例１と同様の回転試験に供した。
焼き付け時間及び含油量の測定結果を、第１表に示す。
【００２５】
○比較例１
樹脂としてポリアミド（ナイロン６６、ガラス繊維３０％含有）〔宇部興産（株）製〕を使用して押出機によりペレット化し、実施例１と同様の冠型保持器に射出成形した後、液温１５０℃のポリα−オレフィン油〔モービル石油化学（株）製ＳＨＦ６１〕中に浸漬した。
このようにして含浸処理された成形体（保持器）を、実施例１と同様の回転試験に供した。
焼き付け時間及び含油量の測定結果を、第１表に示す。
【００２６】
第１表に示される試験結果から、実施例（本発明）の転がり軸受用保持器は、回転前と５００時間回転後の含油量に変化が少なく、潤滑油の保持力に優れることが判る。また、前記保持器を組み込んだ転がり軸受は焼き付き時間が長く、耐久性が格段に向上されたことが判る。
【００２７】
【発明の効果】
以上説明したように、本発明によれば、ポリオレフィン樹脂を軸受用保持器の形状に成形した成形体を潤滑油中で浸漬処理することによって、保持器には一定量の潤滑油が含浸される。しかも、保持器となるポリオレフィン樹脂が潤滑油との親和性が高く、かつ吸油力に優れるために、保持器中の潤滑油の含有量が多くなるとともに、潤滑油の保持力も大きくなり、もって潤滑油が長期間安定して転動体の転動部分に供給される。そのため、この保持器を組込んだ転がり軸受は回転に要するトルクが低減すると共に、このトルクの変動が小さくなる。
また、ポリオレフィン樹脂は吸油力に優れるために、潤滑油の含浸処理に要する時間が短くて済むために、浸漬処理時の加熱による潤滑油の劣化を抑制することができる。
更に、保持器の機械的強度に関しても、保持器形状に成形した後に潤滑油中に浸漬するために、成形時における樹脂と潤滑油との分離に起因するウエルドライン付近での機械的強度の低下を招くことがない。
【図面の簡単な説明】
【図１】転がり軸受を示す要部断面図である。
【図２】図１に示される転がり軸受の保持器を示す斜視図である。
【符号の説明】
１ 内輪軌道
２ 内輪
３ 外輪軌道
４ 外輪
５ 転動体
６ シール板
７ 保持器
８ 主部
９ 保持部
１０ 弾性片[0001]
[Industrial application fields]
The present invention relates to a cage for a rolling bearing.
[0002]
[Prior art]
As shown in FIG. 1, the rolling bearing includes an inner ring 2 having an inner ring raceway 1 on an outer peripheral surface and an outer ring 4 having an outer ring raceway 3 on an inner peripheral surface. A plurality of rolling elements 5 are provided between them so as to be freely rollable.
The outer peripheral edges of both ends of the outer ring 4 are engaged with the outer peripheral edges of the ring-shaped seal plate 6, and the grease present in the installed portion of the rolling element 5 and generated dust (dust generation) are externally provided by both seal plates 6. Or dust that floats outside is prevented from entering the installed portion of the rolling element 5.
[0003]
Further, the plurality of rolling elements 5 are held by a holder 7 as shown in FIG. The cage 7 is integrally formed by injection molding a synthetic resin. That is, the cage 7 includes an annular main portion 8 and a plurality of sets of holding portions 9 provided on one side of the main portion 8. Each holding portion 9 is composed of a pair of elastic pieces 10 that are spaced apart from each other. The mutually opposing surfaces of the pair of elastic pieces 10 constituting each holding portion 9 are concentric spherical or cylindrical concave surfaces. Each rolling element 5 is held by each holding portion 9 so as to roll freely by being pushed between the pair of elastic pieces 10 while elastically expanding the interval between the elastic pieces 10.
[0004]
In general, the material used for the cage 7 is a metal, or a synthetic resin reinforced with injection molding synthetic resin such as polyamide resin, polyacetal resin, polybutylene terephthalate resin or the like, or glass fiber, carbon fiber, organic fiber, etc. A resin composition is used.
The cage 7 has only a function of holding the rolling elements 5, and a lubricating oil or semi-solid lubricant such as grease is used for lubricating the rolling bearing. In particular, when a semi-solid lubricant such as grease is used, the torque required to rotate the shaft, etc. supported by the bearing is large due to the stirring resistance caused by the lubricant, and torque fluctuations with rotation Also tends to be large.
[0005]
Therefore, a rolling bearing in which the cage 7 itself is given a lubricating function has been proposed. For example, Japanese Patent Application Laid-Open No. 61-6429 discloses a bearing cage obtained by impregnating a fluorinated oil with a polyamide-imide resin molded into a porous shape by compression molding. Japanese Patent Laid-Open No. 1-93623 discloses a cage in which lubricating oil is impregnated with a cage in which an oil-containing plastic composed of a binder containing oil and a base material is molded.
[0006]
Further, the present applicant has previously proposed a rolling bearing in which a cage is provided with a lubricating function. For example, in JP-A-6-249244, 0.1 to 0.1 parts by weight of polyamide resin is proposed. A bearing cage impregnated with 1.0% by weight of lubricating oil is disclosed.
Further, as a rolling bearing cage similarly provided with a lubricating function, Japanese Patent Laid-Open No. 6-200947 discloses a bearing holder formed by pressurizing and heating a mixture of ultrahigh molecular weight polyethylene and a lubricant. A vessel is disclosed.
[0007]
[Problems to be solved by the invention]
However, in the case of the bearing cage described in JP-A-61-6429, the cage is porous, and the polyamideimide resin that is the base material of the cage and the fully fluorinated oil that is the lubricating oil Because of the low affinity, the lubricating oil leaks quickly, and the lubricating action disappears early.
Further, in the case of the cage described in Japanese Patent Laid-Open No. 1-93623, since the resin forming the cage is an oil-impregnated resin composition containing about 10% by weight of oil in advance, it is like a cage for a rolling bearing. In a molded product in which a weld line is likely to occur, the resin and the lubricating oil are separated at the time of injection molding, and the mechanical characteristics in the vicinity of the weld line are remarkably deteriorated.
[0008]
Further, in the bearing cage described in Japanese Patent Application Laid-Open No. 6-249244 by the present applicant, since the impregnation amount of the lubricating oil is as low as 0.1 to 1.0% by weight, the cage alone is sufficient. When lubricity may not be obtained, and particularly when durability is required, it is necessary to perform a process such as oil plating of the bearing or addition of grease to the bearing.
Further, in the bearing cage described in Japanese Patent Application Laid-Open No. 6-200947, since the molding material contains a large amount of lubricant, there is a problem in strength when it is formed into a molded body, for example, a reinforcing material or the like. Even if it is used, it is difficult to obtain mechanical strength that can withstand use as a cage. Further, since the use of a large amount of reinforcing material or the like decreases the content of the lubricant, the amount of use is naturally limited, and the mechanical strength cannot be improved. In addition, since the lubricant is held throughout the structure, dimensional shrinkage due to the seepage of the lubricant is large, and the rolling element holding function as a cage cannot be achieved.
[0009]
Therefore, an object of the present invention is to use a polyolefin resin having a high affinity with a lubricating oil as a cage material for a rolling bearing, and by easily and greatly impregnating the lubricating oil into the cage after injection molding, An object of the present invention is to provide a low-cost rolling bearing retainer that performs a stable and stable supply of lubricating oil to a bearing and has good mechanical characteristics.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the rolling bearing cage of the present invention is at least one selected from polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, and copolymers thereof. A molded product formed by molding the polyolefin resin into a desired cage shape by injection molding is obtained by immersing the molded product in lubricating oil, and the lubricating oil is added in an amount of 3 to 10 with respect to 100 parts by weight of the molded product. It is characterized by containing parts by weight.
In the rolling bearing cage,
(1) The lubricating oil is selected from mineral oil, poly α-olefin oil, alkyl polyphenyl ether oil, alkyl naphthalene oil, diester oil, ester oil, polyalkylene glycol oil, and a kinematic viscosity at 40 ° C. of 10 to 150 mm. ² / s der Rukoto,
(2) the polyolefin resin, Rukoto be contained in a proportion of 10 wt% or less of the molding material the total amount of ultra high molecular weight polyethylene,
(3) The molded body contains a whisker-like or fibrous filler, particularly glass fiber ,
Is preferred.
[0011]
[Operation]
The cage is impregnated with a certain amount of lubricating oil by immersing the molded body obtained by molding the polyolefin resin into the shape of the bearing cage in the lubricating oil. Moreover, since the polyolefin resin used as the cage has high affinity with the lubricating oil and excellent oil absorption, the amount of lubricating oil in the cage increases and the holding power of the lubricating oil also increases. Oil is stably supplied to the rolling part of the rolling element for a long period of time. For this reason, the rolling bearing incorporating this cage reduces the torque required for rotation and reduces the fluctuation of this torque.
In addition, since the polyolefin resin is excellent in oil absorption, the time required for the impregnation treatment with the lubricating oil can be shortened, so that deterioration of the lubricating oil due to heating during the immersion treatment can be suppressed.
Furthermore, regarding the mechanical strength of the cage, since it is immersed in lubricating oil after being molded into a cage shape, the mechanical strength near the weld line is reduced due to separation of the resin and lubricating oil during molding. Is not invited.
[0012]
The polyolefin resin used in the present invention is polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, and copolymers thereof, or a combination of two or more. . Regarding polyethylene, any of low molecular weight polyethylene, medium molecular weight polyethylene, and ultrahigh molecular weight polyethylene can be used.
In addition, a whisker-like or fibrous filler can be added to the molding raw material made of these polyolefin resins to the extent that the lubrication performance is not lowered in order to increase the mechanical strength. Specific examples include glass fiber, carbon fiber, aramid fiber, potassium titanate whisker, alumina fiber, silicon nitride fiber, stainless steel fiber, etc., but more preferably glass fiber, carbon fiber, manufactured by DuPont. Examples thereof include Kevlar, Nomex, Technora manufactured by Teijin Limited, and high heat-resistant aramid fiber represented by Conex.
However, when the blending amount of these fillers exceeds 150 parts by weight, melt kneading becomes difficult and a uniform composition cannot be obtained.
[0013]
The polyolefin resin and the filler to be blended as necessary may be kneaded directly using a melt kneader, or after pre-mixing these materials with a mixer such as a Henschel mixer, tumbler, or ribbon mixer in advance. It can also be supplied to a melt kneader. As the melt kneader, a known melt kneader such as a single screw or twin screw extruder, a mixing roll, a pressure kneader, or a Brabender plastograph can be used. What is necessary is just to select suitably the temperature at the time of melt-kneading the temperature which melt | dissolves each component except a filler fully, and does not decompose | disassemble.
[0014]
The cage for a rolling bearing according to the present invention is obtained by molding the molding material obtained by mixing the polyolefin resin or, if necessary, the filler further into a desired cage shape, and then molding the molded body in lubricating oil. It is completed by dipping in
The molding method is a normal injection molding method, and can be performed using, for example, an inline screw type injection molding machine. In addition, when the ultrahigh molecular weight polyethylene is included in the molding base material, the content is desirably 10% by weight or less with respect to the total amount of the molding raw material in consideration of fluidity at the time of melting. If it exceeds 10% by weight, the fluidity is deteriorated and it becomes impossible to mold into a desired shape.
[0015]
The lubricating oil used in the present invention is not particularly limited, but mineral oil, poly α-olefin oil, polybutene, alkyl polyphenyl ether oil such as octadecyl diphenyl ether, alkyl naphthalene oil such as eicosyl naphthalene, di-2-ethylhexyl separator Examples include diester oils such as diisodecyl phthalate, ester oils such as phosphoric ester oils such as tri-2-ethylhexyl phosphate, and polyalkylene glycol oils. In particular, mineral oil, poly α-olefin oil, and alkyl polyphenyl ether oil are preferable.
Moreover, ester oil, polyalkylene glycol oil, etc. with high polarity can also be used, In that case, it is preferable to mix and use oil with low polarity for affinity with polyolefin resin.
[0016]
These lubricants, the polyolefin resin is impregnated so as to range from 3 to 10 wt parts with respect to further retainer 100 parts obtained by molding the molding material prepared by adding a filler as needed. Here, when the amount of the lubricating oil impregnation is less than 3 parts by weight, the amount of the lubricating oil is absolutely insufficient, and the lubricating oil supplied from the cage to the rolling part of the rolling element is depleted at an early stage. If a lubricant (grease or plated lubricant) is not used in combination, the durability of the bearing will be impaired. On the other hand, when the impregnation amount of the lubricating oil exceeds 1 0 part by weight, together with causing a decrease in mechanical strength of the cage, the time required to impregnate the lubricant oil increases, the production efficiency is lowered This will cause the price of the cage to rise.
[0017]
The viscosity of the lubricating oil is not particularly limited, but the kinematic viscosity at 40 ° C. is preferably 10 to 150 mm ² / s, more preferably 10 to 130 mm ² / s. The reason for this is that a low-viscosity lubricating oil having a kinematic viscosity at 40 ° C. of less than 10 mm ² / s has a high penetration rate into the cage and increases the oil content of the cage, but the lubrication impregnated in the cage The oil retainability is poor (leaks out of the cage early) and the lubricant is depleted early. On the other hand, when a high viscosity lubricating oil with a kinematic viscosity at 40 ° C. exceeding 150 mm ² / s is used, not only does this lubricating oil not easily impregnate into the polyolefin resin constituting the cage. The rotational torque of the rolling bearing incorporating the cage of the present invention is also increased.
[0018]
The amount of impregnation of the lubricating oil in the cage increases by heating the lubricating oil to be impregnated at a temperature not higher than the melting point of the polyolefin resin to be used and by increasing the immersion time. However, since the cage is thermally deformed when the liquid temperature of the lubricating oil is too high, it is preferable that the liquid temperature of the lubricating oil is set to be approximately 20 ° C. lower than the melting point of the polyolefin resin and the immersion treatment is performed.
[0019]
The cage of the present invention is formed by blending a polyolefin resin as an essential constituent and, if necessary, a filler component, but in a range that does not impair the purpose of the present invention, further appropriate amounts of various fillers. (Agent) and various stabilizers may be blended. For example, organic fillers, inorganic fillers, antioxidants, UV absorbers, photoprotective agents, heat stabilizers, flame retardants, antistatic agents, peroxide decomposers, fluidity improvers, non-tackifiers, It may contain a release agent, a nucleator, a solid lubricant, a pigment, a dye, and the like.
In addition, the lubricating oil impregnated in the cage of the present invention is an antioxidant, a rust inhibitor, an extreme pressure agent, an oily agent, a viscosity index improver, a wear as long as the object of the present invention is not impaired. An inhibitor or the like may be included.
[0020]
【Example】
Hereinafter, examples and comparative examples will be shown to explain the effects of the present invention, but the present invention is not limited thereto.
[0021]
○ Example 1
As the polyolefin resin, a mixture of 10% by weight of ultra high molecular weight polyethylene [Miperon XM220 manufactured by Mitsui Petrochemical Co., Ltd.] and 60% by weight of low molecular weight polyethylene [PZ50U manufactured by Mitsubishi Oil Chemical Co., Ltd.] is used. After adding 30% by weight of a glass chopped strand (CS3PE-471 manufactured by Nitto Boseki Co., Ltd.) having a cut length of 3 mm and a filament diameter of 13 μm treated with an amino-based silane coupling agent, and premixing with a Henschel mixer, Pelletized.
Then, the pellet was injection molded into the shape of a crown type cage shown in FIG. 2, and the molded body was immersed in a paraffinic mineral oil (FBKRO100 manufactured by Nippon Oil Co., Ltd.) having a liquid temperature of 100 ° C. This immersion treatment was performed by stirring the lubricating oil while bubbling nitrogen gas in a glass container.
The molded body (cage) thus impregnated was incorporated into a miniature ball bearing having an inner diameter of 5 mm, an outer diameter of 13 mm, and a width of 4 mm shown in FIG. 1 and subjected to a rotation test. The rotation test was performed under the conditions of an inner ring rotational speed of 5000 rpm, a thrust load of 3 kgf, and an ambient temperature of 80 ° C., and the bearing seizure time was measured.
The oil content of the cage was also measured at the same time, and the oil content was measured immediately after the immersion treatment and after 500 hours of rotation under the above conditions. The oil content was determined by measuring the weight of the cage before rotation and after rotation for 500 hours, assuming that the weight of the cage (resin and filler) before the immersion treatment was 100.
Table 1 shows the measurement results of the baking time and the oil content.
[0022]
[Table 1]

[0023]
Example 2
As the polyolefin resin, a mixture of ultra high molecular weight polyethylene [Miperon XM220 made by Mitsui Petrochemical Co., Ltd.] 10% by weight and polypropylene [Hypol B-200P made by Mitsui Petrochemical Co., Ltd.] 60% by weight was used as the lubricating oil. A cage was prepared in the same manner as in Example 1 except that a poly α-olefin oil having a liquid temperature of 110 ° C. (SHF61 manufactured by Mobil Petrochemical Co., Ltd.) was used, and the same rotation test as in Example 1 was performed.
Table 1 shows the measurement results of the baking time and the oil content.
[0024]
Example 3
As a polyolefin resin, pellet-shaped polymethylpentene (glass fiber 30% -containing grade, FR-TPX T130) (manufactured by Mitsui Petrochemical Co., Ltd.) was used for injection molding into the same crown type cage as in Example 1. Then, it was immersed in a dialkyl diphenyl ether type synthetic oil [Moleco High Lube-100 manufactured by Matsumura Oil Research Co., Ltd.] having a liquid temperature of 150 ° C.
The molded body (cage) thus impregnated was subjected to the same rotation test as in Example 1.
Table 1 shows the measurement results of the baking time and the oil content.
[0025]
○ Comparative Example 1
Using polyamide (containing nylon 66, 30% glass fiber) as a resin (manufactured by Ube Industries Co., Ltd.), pelletizing with an extruder, injection molding into the same crown-type cage as in Example 1, and a liquid temperature of 150 It was immersed in poly α-olefin oil (SHF 61 manufactured by Mobil Petrochemical Co., Ltd.) at a temperature of ° C.
The molded body (cage) thus impregnated was subjected to the same rotation test as in Example 1.
Table 1 shows the measurement results of the baking time and the oil content.
[0026]
From the test results shown in Table 1, it can be seen that the rolling bearing cage of the example (invention) has little change in oil content before rotation and after 500 hours of rotation, and has excellent lubricating oil retention. Further, it can be seen that the rolling bearing incorporating the cage has a long seizure time, and the durability is remarkably improved.
[0027]
【The invention's effect】
As described above, according to the present invention, the cage is impregnated with a certain amount of lubricating oil by immersing the molded body obtained by molding the polyolefin resin into the shape of the bearing cage in the lubricating oil. . Moreover, since the polyolefin resin used as the cage has high affinity with the lubricating oil and excellent oil absorption, the amount of lubricating oil in the cage increases and the holding power of the lubricating oil also increases. Oil is stably supplied to the rolling part of the rolling element for a long period of time. For this reason, the rolling bearing incorporating this cage reduces the torque required for rotation and reduces the fluctuation of this torque.
In addition, since the polyolefin resin is excellent in oil absorption, the time required for the impregnation treatment with the lubricating oil can be shortened, so that deterioration of the lubricating oil due to heating during the immersion treatment can be suppressed.
Furthermore, regarding the mechanical strength of the cage, since it is immersed in lubricating oil after being molded into a cage shape, the mechanical strength near the weld line is reduced due to separation of the resin and lubricating oil during molding. Is not invited.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a rolling bearing.
FIG. 2 is a perspective view showing a cage of the rolling bearing shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner ring track 2 Inner ring 3 Outer ring track 4 Outer ring 5 Rolling element 6 Seal plate 7 Cage 8 Main part 9 Holding part 10 Elastic piece

Claims (5)

Molding formed by molding at least one polyolefin resin selected from polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, and copolymers thereof into a desired cage shape by injection molding. body, obtained by immersion in lubricating oil, and rolling bearing retainer, characterized in that it contains 3 to 1 0 parts by weight of the lubricating oil to the compact 100 parts by weight. The lubricating oil is selected from mineral oil, poly α-olefin oil, alkyl polyphenyl ether oil, alkyl naphthalene oil, diester oil, ester oil, polyalkylene glycol oil, and a kinematic viscosity at 40 ° C. of 10 to 150 mm ² / s. rolling bearing retainer according to claim 1, wherein the der Rukoto. The polyolefin resin is 1 Symbol placement of the cage for a rolling bearing according to claim characterized that you contained in a proportion of 10 wt% or less of the molding material the total amount of ultra high molecular weight polyethylene. The molded body is rolling bearing retainer according to claim 1 Symbol mounting, characterized in that it contains a filler whiskers or fibers. The filler according to claim 4 Symbol mounting of the rolling bearing, characterized in fiberglass der Rukoto.

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