JPS616429A - Bearing retainer - Google Patents

Abstract

PURPOSE:To obtain long-life lubrication by impregnating 7-17 vol% of polyamide resin having connected pores of a bearing retainer body with complete fluoridized oil. CONSTITUTION:A molded article of a polyamideimide resin 1 is impregnated with complete fluoridized oil by operating air and water in connected pores 2 in an heating and decompressed atmosphere. After impregnation, excessive complete fluoridized oil is removed to complete a bearing regainer. Thus, in addition to self-lubrication of the polyamideimide resin 1 excellent in machinability, lubrication of complete fluoridized oil which is impregnated in the connected pores 2 and gradually oozes out on the surface layer portion and which is excellent in heat-resistance and chemical resistance under the conditions of low vapor pressure and low drift point is added to obtain long-life lubrication which can not be obtained by just oiling.

Description

[Detailed description of the invention] (1) Industrial application fields This invention relates to a bearing retainer.

(2) Conventional technology It is well known that liquid lubricants, semi-solid greases, and solid lubricants have been widely used to reduce the coefficient of friction of sliding materials such as bearings. It is being However, with the rapid progress of science and technology, the conditions under which sliding materials are used have become increasingly strict. For example, turbo pumps for liquid rockets have bearings and mechanical seals that are exposed to cryogenic liquefied gas, so oil and oil cannot be used. , grease or other lubricants cannot be used. Therefore, if a synthetic resin with a low coefficient of friction such as self-lubricating polytetrafluoroethylene resin is used for the bearing cage, or if such a material is used, the cage will loosen as the bearing rotates. A part of the constituent material is transferred to the rolling elements, and further transferred to the raceway surfaces of the inner and outer rings, forming a thin lubricant film over the entire friction surface, producing a lubricating effect.

In addition, there are other methods of plating, coating, or vapor depositing (sputtering) metals such as gold or silver or solid lubricants such as molybdenum disulfide on the inner and outer rings, cages, balls, etc. of the bearing. is also well known.

(3) Problems to be solved by the invention The self-lubricating resins mentioned above, metals such as gold and silver, or solid lubricants such as molybdenum disulfide generally have a less durable lubricant film than oil lubrication. The technical problem of the present invention is to eliminate these drawbacks, as they are significantly inferior, have a short lifespan, and lack reliability.

(4) Means for Solving the Problems In order to solve the problems described in
A bearing cage is provided in which a polyamide-imide resin 1 having communicating holes 2 is impregnated with a completely fluorinated material. The details will be described below. The polyamide-imide resin of this invention (hereinafter referred to as FAI)
Resin) 1 has excellent heat resistance, chemical resistance, mechanical properties, and electrical insulation, and can be melt-molded by extrusion molding, injection molding, etc. However, on the other hand, it has a high water absorption rate. The heat resistance of resin that absorbs a relatively large amount of water decreases. For example, if a molded product is rapidly heated during water absorption, the moisture inside the molded product will turn into high-pressure steam, causing the surface to swell or foam. However, since there is a risk of causing various problems, it can be said that resin is an ideal base material for bearing cages if consideration is given to water absorption.

As such FAI resin 1, for example, Torlon (registered trademark) manufactured by Amoco, USA can be mentioned.

Next, in the present invention, the PAI resin 1 having communicating holes 2 with a volume ratio of 7 to 17% is obtained by classifying and sizing the raw material PAI resin powder (for example, the average particle size is 15 to 50 μm) and using it in a conventional cage. It is obtained by pressurizing it into the same shape and firing it, and by appropriately adjusting the average particle size of the resin, pressure, etc., it is possible to obtain one with continuous pores having a volume ratio of 7 to 17%. At this time, if the raw resin powder contains powder with a fine particle size, it will fill the voids between the particles and increase the variation in the porosity of the product, so the classification and sizing described above is necessary. Become. On the other hand, if the particle size is too large, the voids between the particles become large, which is undesirable because the retention rate (oil retention rate) of the impregnating oil during high-speed rotation, which will be described later, decreases.

Furthermore, before complete fluorination in this invention, it is a compound generally called perfluoropolyether (PFPE) or perfluoropolyalkyl ether (PFAE), such as FOMBLIN manufactured by Montefluos in Italy, as a commercial example. I can do it. Before complete fluorination, it is extremely stable and inert, and has excellent heat resistance, chemical resistance, oxidation resistance,
It has excellent solvent resistance and lubricity, does not produce solid deterioration products even when exposed to high temperature and high energy radiation, has a low vapor pressure (for example, 1O-13TO "r" at 20℃), and has a low It has characteristics such as a pour point (for example, -80°C).

As mentioned above, <t, □All'2 and the resin. In order to impregnate a molded product before complete fluorination, it is preferable to operate under a heated and reduced pressure atmosphere to facilitate the removal of air and moisture in the pores. By removing , the bearing retainer of the present invention can be obtained.

(5) In addition to the self-lubricating properties of the FAI resin 1, which has excellent heat resistance and good workability and forms the matrix of the working cage, it is impregnated into the communicating holes 2 of this resin and is removed from the surface layer. With the addition of the gradually increasing low vapor pressure, low pour point, heat resistance (cold resistance), and chemical resistance before complete fluorination, it provides extremely long-life lubrication that cannot be obtained with simple lubrication. will be demonstrated.

(6) Examples and Comparative Examples [Examples 1 to 3] PAI resin powder (Nidoron 4000 manufactured by Amoco, USA)
TF) is classified and sized, pressurized and fired under the molding conditions shown in Table 1 to form a molded body with continuous holes (outer diameter 3 Q).
mm, thickness lQmm) was obtained.

These molded bodies were then immersed in a pre-fluorinated solution (manufactured by Monte Fluos: Vonprin Z25) at 23° C. under reduced pressure (I Torr ) to impregnate the pre-fluorinated solution into the open pores of the compact. . Remove the excess oil adhering to the surface of the impregnated molded product with a clean cloth, and use a centrifuge to apply a centrifugal force of 8000 G at room temperature (Table 23, Table 1). %) was determined, and the results are shown in Figure 2.

Even after 300 hours, the oil content remained almost constant, and as shown in Table 2, the lubrication performance (friction torque) was excellent enough to withstand use at both low and high temperatures, as well as under low pressure. It was something. The friction torque was determined under the conditions of a #7204 bearing, a rotational speed of 1100 Orp, and a thrust load of 5 kgf.

Table 2 [Comparative Examples 1 to 4] Raw powder of the PAI resin used in Examples 1 to 3, which was not classified and sized as it is, was 11 classified and sized and had an average particle size of 114 μm, and fine powder that had been classified and sized and had an average particle size of 114 μm; Coarse powder with an average particle size of 89μm, and another unclassified product with an average particle size of 24.6μm.
Powder No. m was pressed and fired under the conditions shown in Table 3 to obtain molded bodies having the same shapes as those of Examples 1 to 3. These molded bodies were subjected to the same impregnation treatment as in Examples 1 to 3, and at the same time, changes in oil content percentage and lubrication performance due to application of centrifugal force were examined. Changes in oil content are summarized in Figure 3. Furthermore, the lubrication performance was large and unstable in terms of frictional torque. Furthermore, the change in oil retention capacity (oil retention rate) of the cage of the present invention due to temperature rise was investigated, and the results are shown in FIG. (Heating for 1 hour) In Figure 3, the change in oil content of Comparative Example 1 appears to be stable, but the oil content of the same end-classified product (Comparative Example 4) is small, and the oil retention in Figure 4 Since the yield rate is significantly lower than that of classified products, quality stability cannot be achieved with unclassified products. Furthermore, when the composition is mainly composed of fine powder as in Comparative Example 2, the oil content is low and is therefore inappropriate. In addition, a product using coarse powder as in Comparative Example 3 releases a large amount of oil at the beginning of centrifugal force application, and cannot be expected to provide long-life lubrication.

Comparative Examples 1 to 4 were not all satisfactory compared to Examples 1 to 3.

(7) Effects The bearing cage of the present invention has a lower torque than conventional solid lubrication, and the alloy impregnated oil contained inside the cage gradually oozes out to provide oil lubrication. This will fully compensate for the shortcomings. Therefore, the bearing cage of the present invention combines the self-lubricating properties of the I'AI resin itself and the excellent properties of the fully fluorinated oil impregnated with it, making it suitable for use in, for example, Bakelite cages. Compared to when the cage is in use, the cage will not wear out and its life will be extended by more than 2.5 times. In addition, the cage of this invention can withstand use from a low temperature of -60°C to a high temperature of 200°C, and can also be used in an ultra-vacuum of 10-9 Torr. In addition to being used at low temperatures, this product plays an important role that conventional products could not play in special applications where high speed and long life are strongly required, such as ship gyros, even in the air. It can be said that the significance of this invention is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a perspective view illustrating the bearing retainer of the present invention, and Figs. 2 and 3 show the time course of the oil content when loaded with centrifugal force (8000G) in the example and comparative example, respectively. 4 are diagrams showing the relationship between temperature and oil retention rate in Examples and Comparative Examples of the present invention. 1... Polyamideimide (PAI) resin, 2...
...Connecting hole Agent sickle 1) Sentence 2 Figure 1 □ Time diagram Figure 4

Claims (1)

[Claims] A bearing retainer made by impregnating fully fluorinated oil into a polyamide-imide resin having 7 to 17% by volume of communicating pores.