JP2017141951A - Rolling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce torque while maintaining advantages of microcapsules.SOLUTION: A rolling device has an outer member, an inner member, and a rolling element and is lubricated with a lubrication medium that comprises microcapsules containing lubricant compositions and a lubricant, at the ratio of microcapsules: lubricant=50-100: 50-0 (mass%) based on the total content of both.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rolling device, and more particularly to a rolling device that reduces torque.

  In rolling bearings used for cooling fan motors, in-vehicle motors and the like, low torque is strongly demanded in order to reduce power consumption. To reduce the torque of a rolling bearing, it is common to apply oil plating, reduce the amount of grease, or use grease with a low consistency.

  In addition, the use of microcapsules containing a lubricating component, an additive, or the like is also performed. The microcapsules are sent to the bearing area and the friction part of the bearing, and are physically broken at these parts to release the inclusion material, thereby contributing to lubrication. Further, since the encapsulating material is not discharged from the microcapsules that have not been destroyed, the torque is not increased due to the extra encapsulating material.

  As a conventional technique using such a microcapsule, the present applicant also disclosed, for example, in Patent Documents 1 to 4, a microcapsule containing a highly heat-resistant base oil and a thickener, a microcapsule containing various additives, and solid lubrication. It has been proposed to lubricate with a grease composition containing a microcapsule containing an agent, gelatin or wax containing a lubricating oil, and microcapsules made of agar in a proportion of several mass%.

JP 2007-99944 A JP 2007-177097 A JP 2008-31254 A JP 2009-203327 A

  However, in Patent Documents 1 to 4, although the microcapsule is used, the grease composition is mainly used, and the agitation resistance and rolling viscosity resistance of the grease composition occupy most, so that the bearing torque is further reduced. I can't. Rather, the torque is further increased by the inclusion material discharged due to the destruction of the microcapsules.

  In addition, oil plating lubrication is sometimes used as a means for reducing torque, but even in this oil plating lubrication, further reduction in torque is required, and it is considered to reduce the amount of oil. . However, reducing the amount of oil in the oil plating lubrication is not preferable because the durable life is reduced.

  Therefore, an object of the present invention is to further reduce the torque while maintaining the advantages of the microcapsule.

In order to solve the above problems, the present invention provides the following rolling device.
(1) While comprising an outer member, an inner member, and a rolling element,
Lubricating the microcapsules encapsulating the lubricant composition and the lubricating oil with a lubricating medium containing a ratio of microcapsules: lubricating oil = 50 to 100: 50 to 0 (mass%) with respect to the total amount of both. A rolling device characterized by.
(2) Microcapsule: Lubricating oil = 50-70: 50-30 (mass%), The rolling device as described in said (1) characterized by the above-mentioned.
(3) The rolling device according to (1) or (2) above, comprising a crown type cage.

  In the rolling device of the present invention, lubrication is performed with a lubricating medium containing a specific ratio of microcapsules encapsulating a lubricant composition and lubricating oil, so that the torque can be greatly reduced compared to a grease composition in which microcapsules are dispersed. Can be achieved. In addition, it has durability equivalent to or better than oil plating lubrication.

It is sectional drawing which shows an example of the rolling device of this invention. It is a graph which shows a time-dependent change of the bearing torque of an Example and a comparative example. It is a graph which shows the measurement result of the durable time of an Example and a comparative example.

  Hereinafter, the present invention will be described in detail.

  In the present invention, the type of rolling device is not limited, and various rolling devices that require low torque, such as a rolling bearing used in a cooling fan, an in-vehicle motor, or the like, can be targeted. For example, the ball bearing shown in FIG. 1 can be illustrated. The ball bearing shown in the figure has an inner ring 1 (inner member) having an inner ring raceway surface 1a on the outer peripheral surface thereof, and an outer ring raceway surface 2a on the inner peripheral surface thereof. A plurality of balls 3 (rolling elements) are held by a retainer 4 so as to be able to roll between the outer ring 2 (outer member) having the inner ring 1 in order to prevent foreign matter from entering from the outside. And the outer ring 2 are sealed by shields 5 and 5. The cage 4 is preferably a crown type cage. And in this invention, it lubricates with the lubricating medium which contains the microcapsule 6 which encapsulated the lubricant composition, and lubricating oil in a specific ratio.

  The microcapsule refers to a microcapsule in which a substance according to the purpose is encapsulated as a core substance. Although the size is not particularly limited, a size of several μm to several thousand μm is often used.

  The lubricant composition contained in the microcapsule 6 is preferably only a lubricating oil, but may be a grease composition based on the lubricating oil and increased with a thickener, and various additives may be added. May be included.

  Although there is no restriction | limiting in lubricating oil (or base oil), What is generally used as base oil of lubricating oil or a grease composition can be used. Specifically, mineral oil, synthetic oil, animal and vegetable oils, etc. can be used.

  As the mineral oil, one obtained by appropriately combining pressure distillation, oil removal, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, white clay purification, hydrorefining, and the like can be used.

  Synthetic oils include hydrocarbon oils, ester oils, ether oils, silicone oils, fluorine oils and the like. Examples of the hydrocarbon oil include poly-α-olefins such as normal paraffin, isoparaffin, polybutene, polyisobutylene, 1-decene oligomer, 1-decene and ethylene co-oligomer, and hydrides thereof. Further, alkylbenzenes such as monoalkylbenzene, dialkylbenzene, and polyalkylbenzene, and alkylnaphthalenes such as monoalkylnaphthalene, dialkylnaphthalene, and polyalkylnaphthalene are also included. Examples of ester oils include dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl glutarate, and methyl acetyl cinnolate, trioctyl trimellitate, tridecyl tritriate Aromatic ester oils such as melitrate and tetraoctyl pyromellitate, polyol ester oils such as trimethylolpropane caprylate, trimethylolpropane verargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol verargonate, etc. Examples include complex ester oils that are oligoesters of mixed fatty acids of basic and dibasic acids and polyhydric alcohols. Examples of ether oils include polyethylene glycol, polypropylene glycol, polyethylene glycol monoether, polypropylene glycol monoether and other polyglycols, monoalkyl triphenyl ether, alkyl diphenyl ether, dialkyl diphenyl ether, tetraphenyl ether, pentaphenyl ether, monoalkyl tetraphenyl ether. And phenyl ether oils such as dialkyl tetraphenyl ether, (di) alkyl diphenyl thioether oil, (di) alkyl polyphenyl thioether oil, tetraphenyl thioether oil, pentaphenyl thioether, and the like. Other synthetic oils include tricresyl phosphate and perfluoroalkyl ether.

  Examples of animal and vegetable oils include beef tallow, lard, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, and other oils and hydrides thereof.

These lubricating oils preferably have a kinematic viscosity of 10 to 1000 mm ² / s (40 ° C.) in view of lubricity. When the kinematic viscosity is less than 10 mm ² / s (40 ° C.), only a thin oil film can be formed, resulting in poor durability. Moreover, when it exceeds 1000 mm < ² > / s (40 degreeC), even if it is a small amount, a torque will become large.

  The thickener is not limited as long as it can retain the above lubricating oil in a gel form, such as calcium soap, aluminum soap, sodium soap, calcium complex soap, aluminum complex soap, lithium complex soap and the like conventionally used in grease compositions. Metal soap, aromatic urea, aliphatic urea, alicyclic urea, triurea, urea compounds such as tetraurea, fluorine resins such as sodium terephthalate, PTFE, organic bentonite, silica gel, and the like can be used. Moreover, there is no restriction | limiting also in the compounding quantity, The grease property should just be maintained.

  As additives, conventionally used, for example, antioxidants such as phenols, sulfurs, zinc dithiophosphates, zinc dithiocarbamates, metal salts of sulfonates, esters, metal salts of naphthenates, succinic acid derivatives, etc. Antirust agents, extreme pressure agents such as phosphorus, zinc dithiophosphate and organic molybdenum, oiliness improvers such as fatty acids and animal and vegetable oils, metal deactivators such as benzotriazole, etc. can be added in an appropriate amount depending on the purpose. .

  The method for producing the microcapsules is not particularly limited, and is an interfacial polymerization method, an in situ polymerization method, a phase separation method, a liquid drying method, an orifice method, a spray drying method, an air suspension coating method, a hybridizer. Law. Among these, the in situ polymerization method is preferable. Further, if the microcapsules are produced by the in situ polymerization method using the melamine resin composition as a material, microcapsules excellent in heat resistance and durability can be obtained.

  Examples of the outer material of the microcapsule include polyurea, polyurethane, polyamide, melamine resin, carbon resin, alginic acid, calcium chloride, gelatin, gum arabic, starch, wax, cellulose, titanium dioxide, polyethylene, and polymethyl methacrylate. It is appropriately selected depending on the encapsulating material and the manufacturing method. Moreover, in the microcapsule 6, the outer material and the lubricant composition that is the above-described inclusion material are preferably in the mass ratio of the outer material: the inclusion material = 6 to 1: 4 to 9.

  The lubricating medium may be the microcapsule 6 alone, but a lubricating oil may be used in combination. When the lubricating oil is used in combination, the lubricating oil is 50% by mass or less based on the total amount with the microcapsules 6. That is, the microcapsule 6 is a ratio of 50 to 100% by mass with respect to the total amount with the lubricating oil. Preferably, the microcapsule 6 and the lubricating oil are microcapsule: lubricating oil = 50 to 70:50 to 30 (mass%).

  The lubricating oil used in combination is preferably the same as the lubricating oil contained in the microcapsule 6 because of compatibility.

  An appropriate amount of the lubricating medium may be sealed in the space formed by the inner ring 1, the outer ring 2 and the balls 3, or the minimum amount necessary for lubrication may be used as shown in the figure. Even with the minimum required amount, as the bearing rotates, the oil film from the broken microcapsule 6 becomes one as in the case of oil plating on the rolling surfaces of the inner ring raceway surface 1a, outer ring raceway surface 2a, and balls 3. The same durability as oil plating lubrication can be obtained. And, by making the required minimum amount, a significant reduction in torque is realized. In FIG. 1, the microcapsule 6 is indicated by a dot, and shows a state in which the microcapsule 6 is attached to the rolling surface of the ball 3.

  The lubricating medium may be sealed after applying a small amount of a rust preventive agent inside the bearing, or may be sealed after cleaning and degreasing inside the bearing.

The amount of the lubricating medium enclosed in the bearing is 0.1 to 50 with respect to the spatial volume of the bearing excluding the volume of the balls 3 and the cage 4 from the spatial volume surrounded by the inner ring 1, the outer ring 2 and the shield 5. % Is preferable, and more preferably 5 to 40%. Further, the amount of the lubricant composition enclosed in the microcapsule 6 in the space volume of the bearing is preferably 0.001 to 0.100 g / cm ³ . Furthermore, the total amount of oil sealed in the bearing, that is, the total amount of the lubricating oil or base oil contained in the microcapsule 6 and the lubricating oil used in the lubricating medium is 0.001 to 0.00 in the space volume of the bearing. 3 g / cm ³ is preferred.

  As described above, the embodiment of the present invention has been described by taking the ball bearing shown in FIG. 1 as an example, but can be applied to a roller bearing with a cage, a total rolling bearing, a full roller bearing, etc. However, it may be double row.

  The present invention will be further described below with reference to examples, but the present invention is not limited thereto.

Example 1 (lubricating medium: only microcapsules)
The following microcapsules were prepared by the interfacial polymerization method.
- shell material: melamine-containing ^{material: PAO (48mm 2 / s @} 40 ℃)
-Microcapsule outer diameter: average particle size 10 μm
-Ratio of the encapsulating material shown in the entire microcapsule: 60% by mass

Then, the single row deep groove ball bearing (name number 608: inner diameter 8 mm, outer diameter 22 mm, height 7 mm, space volume 0.56 cm ³ , equipped with a crown type cage and a shield) was removed, and the antirust agent was removed. After that, a shield was attached to the opening on the opposite side of one of the crown-shaped cages between the inner and outer rings. Thereafter, the microcapsule was dropped on the ball while rotating the bearing with the opening on the other side facing upward. The microcapsules adhered uniformly to the balls, the outer ring raceway surface, and the inner ring raceway surface with the rotation of the bearing. Thereafter, a shield was attached to the opening on the other side to obtain a test bearing. The encapsulation amount of the microcapsule is 0.007 g (the total amount of the outer material and the inner material; 5.26% with respect to the space volume of the bearing). In order to uniformly adhere the powder-like microcapsules to the raceway surface of the bearing, it is preferable to drop it on the ball as in this embodiment, and the cage is a crown type cage having an opening. preferable.

Example 2 (Lubricating medium: only microcapsules)
A microcapsule similar to that in Example 1 was prepared except that PAO (396 mm ² / s @ 40 ° C.) was used as the encapsulating material. Then, 0.007 g of this microcapsule was sealed in a deep groove ball bearing similar to that in Example 1 (5.26% with respect to the space volume of the bearing) to obtain a test bearing.

Example 3 (lubricating medium: microcapsule + lubricating oil)
The microcapsules of Example 1 and PAO (48 mm ² / s @ 40 ° C.) were mixed in the same amount and sealed in the same deep groove ball bearing as in Example 1 to obtain a test bearing. The total amount of encapsulation of the microcapsules and the lubricating oil is 0.04 g (26.7% with respect to the space volume of the bearing).

Example 4 (lubricating medium: microcapsule + lubricating oil)
The microcapsule of Example 1 and PAO (48 mm ² / s @ 40 ° C.) were mixed at microcapsule: PAO = 70: 30, and sealed in a deep groove ball bearing similar to that of Example 1, did. The total amount of sealed microcapsules and lubricating oil is 0.026 g (18.0% with respect to the space volume of the bearing).

Comparative Example 1 (lubricating medium: oil plating)
Using a deep groove ball bearing of the same type as in Example 1, PAO (48 mm ² / s @ 40 ° C.) was oil plated to obtain a test bearing. The coating amount was 0.04 g (9.0% with respect to the space volume of the bearing).

  The specifications of the lubricating media of the examples and comparative examples are shown in Table 1.

  Using the test bearings of Examples 1 to 4 and Comparative Example 1, the following (1) torque characteristic evaluation and (2) durability evaluation were performed.

(1) Torque measurement evaluation The test bearing was rotated under the following conditions, and the change with time in the bearing torque was determined. The number of tests was 3, and the average value was calculated.
・ Inner ring rotation speed: 5000 min ⁻¹
-Fa load: 29.4N
・ Temperature: normal temperature ・ Measurement time: 3600 seconds

(2) Durability Evaluation Under the following conditions, the time until the test bearing was locked (durability time) was measured. The number of tests was 6, and the average value was calculated.
・ Inner ring rotation speed: 4000 min ⁻¹
-Fa load: 88.2N
・ Temperature: 140 ℃

  (1) The results of changes over time in the torque of the bearing are shown in FIG. 2, and Examples 1 and 2 are microcapsule lubrication, and Examples 3 and 4 are lubrication systems using both microcapsules and lubricating oil. Compared with the comparative example 1 which is oil plating lubrication, it can be seen that the torque is very low after the torque is stabilized. In addition, (2) results of durability evaluation are shown in FIG. 3, and Examples 1 and 2 which are microcapsule lubrication, and Examples 3 and 4 which are lubrication systems using a combination of microcapsules and lubricating oil, It can be seen that it has durability equal to or higher than that of Comparative Example 1 which is oil plating lubrication.

  Further, in Examples 3 and 4, although the torque is the same as in Examples 1 and 2, the total amount of lubricating oil sealed in the bearing is increased, so that the durability life is extended. From this, it can be said that it is preferable to use a lubricating medium in which microcapsules and lubricating oil are used in combination.

  When Example 3 is compared with Comparative Example 1, the total amount of lubricating oil sealed in the bearing is smaller in Example 3, but in Example 3, the torque is lower and the durability life is longer. The reason why the torque is low is that the lubricating oil from the microcapsule cracked on the raceway surface is gradually lubricated to suppress excessive stirring resistance and rolling viscous resistance to the limit. It is conceivable that the evaporation amount of the lubricating oil can be suppressed by encapsulating the lubricating oil in the microcapsule.

  When Example 1 and Comparative Example 1 are compared, Example 1 is less than Comparative Example 1 in terms of the total amount and amount of lubricating oil sealed in the bearing, but the durability life is equivalent to Comparative Example 1, and Comparative Example The torque is lower than 1. The reason for the lower torque is lubrication with microcapsules only, and the oil is gradually lubricated only with the lubricating oil coming out of the microcapsules cracked on the raceway surface, minimizing excess stirring resistance and rolling viscous resistance. The reason why the durable life is extended is that the evaporation amount of the lubricating oil can be suppressed by encapsulating the lubricating oil in the microcapsule.

  As described above, a rolling bearing having a low torque and excellent durability compared to the oil plating lubrication system can be provided by the lubrication system using the microcapsule or the microcapsule and the lubricating oil in combination as in the present invention. .

1 Inner ring (inner member)
2 Outer ring (outer member)
3 balls (rolling elements)
4 Cage 5 Shield 6 Microcapsule

Claims (3)

While having an outer member, an inner member, and a rolling element,
Lubricating the microcapsules encapsulating the lubricant composition and the lubricating oil with a lubricating medium containing a ratio of microcapsules: lubricating oil = 50 to 100: 50 to 0 (mass%) with respect to the total amount of both. A rolling device characterized by.   The rolling device according to claim 1, wherein: microcapsule: lubricating oil = 50 to 70:50 to 30 (mass%).   The rolling device according to claim 1, further comprising a crown type cage.

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