JPH0492116A - Material for antifriction bearing holder - Google Patents

Abstract

PURPOSE:To permit use under severe conditions and obtain a material which is excellent in slide characteristics and wear resistance by using tetrafluoroethylene resin containing magnesium oxide. CONSTITUTION:Tetrafluoroethylene resin containing magnesium oxide is used as a material for an antifriction bearing holder. The material for the antifriction bearing holder is provided with wear resistant characteristics added by magnesium oxide to the tetrafluoroethylene resin which is a main mold material and has self lubrication, so that the material is excellent in wear resistance and lubrication even at an extremely low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a retainer for a rolling bearing.

[Conventional technology]

Rolling bearings are usually filled with grease or circulated with lubricating oil to reduce sliding friction and prevent wear or heat generation. However, when such rolling bearings are used in high vacuum, grease or lubricating oil Not only will the lubricant be lost, but the dissipated lubricant may contaminate surrounding equipment and cause an accident. Furthermore, if such a bearing is to be used in an extremely low temperature atmosphere such as liquid hydrogen, the lubricant such as grease or oil will freeze, making it impossible to operate the bearing. Therefore, in order to avoid using lubricants that cause dissipation and freezing, materials with self-lubricating properties, such as solid lubricants such as molybdenum disulfide or lubricating materials such as polytetrafluoroethylene resin (polytetrafluoroethylene), should be used. Polymers with
A method of coating the sliding surface by means such as sputtering (ion blasting, vapor deposition, etc.) has been adopted. However, methods using vacuum equipment such as sputtering require complicated equipment and difficult to set conditions, and the polymer may also lose its lubricating properties, making it unfavorable in terms of workability and economy. I cannot say that it is.

In addition, as a method to utilize the lubricating properties of tetrafluoroethylene resin as is, this polymer powder was used as polyamide-imide,
Coating with polyimide, phenol resin, etc. as a binder may be used, but with such a method, the coating becomes thick and it is difficult to set the bearing clearance. It is also possible to use synthetic resin with self-lubricating properties as a material for forming the retainer of the bearing, but it can withstand use at high vacuum or extremely low temperatures,
Moreover, a synthetic resin bearing with excellent sliding properties, particularly wear resistance, could not be obtained.

(Problem B to be solved by the invention) As described above, in the conventional technology, there is a problem that it is not easy to obtain synthetic resin rolling bearings that can withstand use under harsh atmospheres such as high vacuum or extremely low temperatures. Therefore, it has been a challenge to obtain a material that can be used under the above-mentioned harsh conditions and has excellent sliding properties and wear resistance.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention adopts a method of making a rolling bearing retainer material made of tetrafluoroethylene resin containing magnesium oxide. below,
I will explain the details.

First, the tetrafluoroethylene resin (hereinafter abbreviated as PTFE) used in this invention is a fluororesin made of a homopolymer of tetrafluoroethylene, and is manufactured by Alboflon (manufactured by Montegisson, Italy), Fluon (manufactured by ICI, UK).・It is commercially available under registered trademark names such as Teflon (manufactured by DuPont, USA), Polyflon (manufactured by Daikin Industries, Ltd.), etc., and although compression molding is possible, injection molding is not possible. .

Next, magnesium oxide (hereinafter MgO
It is desirable that the average particle diameter of the particles (abbreviated as ) is 50- or less, and particularly preferably 25-tna or less. This is because if the average particle size of go is larger than 50 pm, when mixed with PTFE, the dispersibility will be poor, the original characteristics of PTFE will not appear in the molded product, and the wear resistance will be poor, which is undesirable. The amount of MgO added to PTFE is preferably 2 to 1%. because,
This is because if the amount is less than 2% by weight, the effect of improving wear resistance will be small, and if the amount is more than 50% by weight, the friction properties will be deteriorated, which is undesirable.

In this invention, various fillers may be added as long as they do not impair the effects of the invention. Examples of the filler include polyamideimide resin, polyetherimide resin, polyarylene sulfide resin, aromatic polyetherketone resin, polyarylene ether sulfone resin, phenolic resin, aromatic polyester resin, polyimide resin, and silicone resin. In addition to heat-resistant polymer materials such as molten fluororesin, heat-resistant inorganic materials such as glass fiber, carbon fiber, graphite fiber, wollastonite, ceramic fiber, potassium titanate fiber, steel wire, copper wire, and stainless steel wire. heat-resistant inorganic composite fibers such as so-called boron fibers or silicon carbide fibers, heat-resistant organic fibers such as aromatic amide fibers, graphite or zinc, aluminum, silver, molybdenum,
Inorganic powders such as tungsten, niobium, glass peas, silica balloons, diatomaceous earth, and asbestos, as well as inorganic powders for improving lubricity such as molybdenum sulfide, graphite, carbon, mica, talc, and molybdenum dioxide, iron oxide, cadmium sulfide, and selenium. There are many examples including inorganic pigments for coloring such as cadmium oxide and carbon blank.

When mixing and molding these raw materials,
It is sufficient to mold the filler-containing PTFH under the usual molding conditions that have been widely used in the past. For example, dry mixing is performed using a mixer such as a tumbler mixer or a Henschel mixer, and the mixture is put into a mold and molded at 380 to 600 kg/cff.
A method in which the compression molded body taken out from the mold is sintered at 370°C after preforming by applying a pressure of 1 liter, a method in which compression molding is performed batchwise while heating and pressurizing, or a continuous molding method using a ram extruder, etc. It may be either.

Further, the inner ring, outer ring, and rolling elements of the bearing may be sputtered or coated with a solid lubricant or the like to the extent that the effects of the present invention are not impaired.

[Function] The above-described rolling bearing retaining material of the present invention has wear resistance properties added to the self-lubricating tetrafluoroethylene resin, which is the main molding material, by magnesium oxide, so it can withstand extremely low temperatures. The material also has excellent wear resistance and lubricity, and can be made into a molded product with such characteristics and used under high vacuum conditions.

[Example] Raw materials used in Examples and Comparative Examples of the present invention are shown below.

■PTFE (manufactured by Hoechst: TFM1700) ■M
gO (manufactured by Wako Pure Chemical Industries, Ltd.: reagent, average particle size 21 utr+
)■Calcium carbonate (manufactured by Nichitsu Kogyo Co., Ltd.: NA600)■
Molybdenum (manufactured by Nihon Shinkinzoku Co., Ltd.: molybdenum powder) ■Molybdenum disulfide (manufactured by Dow Corning Co., Ltd.: Molycoat Micro Size) ■Lead oxide (manufactured by Shinyo Kako Co., Ltd.: Resurge S) ■Magnesium fluoride (manufactured by Wako Pure Chemical Industries, Ltd.) : Reagent) ■Magnesium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.: Reagent) Example 1: After dry mixing the above raw materials at the proportions (wt%) shown in the table, this was put into a mold and 500 kg/ The compression molded product was preformed at a pressure of - and fired at 370°C. A cylindrical test piece with a diameter of 3 m+ was prepared from this fired product, and the wear coefficient and amount of wear under low temperature conditions were measured.

Friction coefficient, wear amount: Using a bottle-on-disk friction and wear tester that can measure in a cryogenic atmosphere, the friction coefficient and The amount of wear (mm) was determined.

Comparative Examples 1 to 7; Except for not adding MgO, operations were performed in exactly the same manner as in the examples, and the measurement results of the obtained friction coefficient and amount of wear are also shown in the table. In addition, *marks 1 to 4 in the table indicate the operating times of the bottle-on-disc friction and wear tester of 35 minutes, 12 minutes, 2 minutes, and 2 minutes, respectively, because the amount of wear on the test piece exceeds the allowable value of the tester.
Indicates that the time limit is 10 minutes.

As is clear from the friction coefficient and wear amount values in the table,
The PTFE containing hgo shown in Example 1 had a small coefficient of friction and excellent sliding properties under extremely low temperature conditions. On the other hand, Comparative Examples 1 to 7, which use fillers other than MgO or do not use fillers at all, have poor wear resistance, especially Comparative Example 2.
-7 showed a wear amount of 0.78 mm or more at each test time (2 to 35 minutes).

is the optimal one. Therefore, it can be said that the significance of this invention is extremely large.

Claims (1)

[Claims] (1) A retainer for a rolling bearing characterized by being made of tetrafluoroethylene resin containing magnesium oxide.