JPH06313435A - Corrosion resistant rolling bearing - Google Patents

Abstract

PURPOSE:To provide a low cost corrosion resitant rolling bearing having long life wherein lubricating oil can be automatically supplied for long periods, and the generation of rust is restrained even in the corrosive atmosphere such as in water. CONSTITUTION:Lubricating oil contained polymer 15 is filled in the space sandwiched between an outer race 11 and an inner race 12 made of corrosion resistant materials and shutted off from outside. The lubricating oil contained polymer 15 includes one or plural polymers to be selected from the different kinds of polymer groups having the basically same chemical constitution, and the sum of the content of polymer in the lubricating oil contained polymer 15 is 5 to 90 weight %, while the lest part is lubricating oil. Lubricating oil seeps gradually with time and is uniformly supplied to the contact surface of a bearing washer and a rolling element 13 in every nook and cranny.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrosion resistant rolling bearing which can be suitably used in water or in a corrosive gas atmosphere.

[0002]

2. Description of the Related Art As a conventional corrosion-resistant rolling bearing, for example, there is one disclosed in Japanese Utility Model Laid-Open No. 4-82431. In this structure, the outer ring, the inner ring, and the rolling elements are made of ceramics, and the cage is made of a PTFE-based self-lubricating composite material.

[0003]

However, the above conventional corrosion-resistant rolling bearing has the following problems. By using the PTFE self-lubricating composite material for the cage, the PTFE is transferred from the cage to the rolling elements during the operation of the bearing.
The material is transformed and lubricated by utilizing its self-lubricating property. However, it is difficult that the cage and the rolling elements are always in contact with each other on an average, and the lubricating coating of the PTFE material is uniformly formed on the entire surface of the rolling element. Therefore, it is difficult to obtain stable lubrication. The PTFE material merely mechanically adheres to the surface of the rolling element, and cracks and peeling occur in a short time.

Since expensive ceramics are used for the outer ring, the inner ring and the rolling elements, the cost becomes very high. Therefore, the present invention has been made by paying attention to such a conventional problem, without using a particularly expensive material, it is possible to automatically and stably supply the lubricating oil for a long period of time, and It is an object of the present invention to provide a low-cost, long-life corrosion-resistant rolling bearing that suppresses rust generation even in a corrosive atmosphere such as water.

[0005]

A rolling bearing of the present invention which achieves the above object comprises an outer ring, an inner ring and a rolling element having corrosion resistance, and a lubricating oil is contained in a space sandwiched between the outer ring and the inner ring. A polymer is filled, the lubricating oil-containing polymer comprises one or more polymers selected from the group of heterogeneous polymers, including those having basically the same chemical structure but differing only in average molecular weight, and The total content of the polymers in the lubricating oil-containing polymer is 5 to 90% by weight, and the balance is the lubricating oil.

Here, the above-mentioned polymer is a poly-α-olefin polymer and has an average molecular weight of 1 × 10 ³ -1.
× 10 ^{6 It is} preferably composed of a low molecular weight compound having a molecular weight of 1 × 10 ^{3 to} 5 × 10 ^{5 and} a high molecular weight compound having an average molecular weight of 1 × 10 ^{6 to} 5 × 10 ⁶ , and a compounding ratio of low molecular weight: high molecular weight is 8 :
It can be in the range of 2 to 1: 9.

Further, the above lubricating oil may contain 0.01 to 0.1% by weight of a fluorine-based surface-active substance. Further, the above-mentioned polymer may be obtained by adding a thermoplastic or thermosetting resin to a poly α-olefin-based polymer.

[0008]

In the rolling bearing of the present invention, the lubricating oil-containing polymer is filled in the space between the outer ring and the inner ring. When the bearing is operated, the lubricating oil contained in the lubricating oil-containing polymer gradually exudes over time. And
Since it is uniformly supplied to the contact surface between the bearing ring and the rolling element, the rolling bearing does not seize in a short time.

Further, the outer ring, the inner ring, and the rolling elements have corrosion resistance, and their contact surfaces are covered with a polymer containing lubricating oil to be shielded from the outside. Therefore, even if the rolling bearing is placed in water or an atmosphere of corrosive gas, the inside of the bearing is protected from the corrosive atmosphere. Due to these effects, the rolling bearing of the present invention can exhibit a stable bearing function for a long period of time even in a corrosive atmosphere.

The present invention will be described in more detail below. The rolling bearings targeted by the present invention include all types of radial ball bearings, radial roller bearings, thrust ball bearings. It is a thrust roller bearing, and the contact mode between the outer ring, the inner ring, and the rolling elements may be radial or axial contact, angular contact, or self-alignment. Further, the type of the retainer may be any of a press retainer, a machined retainer, a molded retainer, a pin retainer, and the like, and a type not having such a retainer is also included. Further, it can be applied to both those having a seal and a shield and those not having one.

The materials of the outer ring, the inner ring, the rolling elements and the cage, which are the components of the rolling bearing of the present invention, will be described below.
In the present invention, stainless steel can be used as the material for these bearing components. In this case, not only corrosion resistance but also rolling fatigue strength and wear resistance are required at the same time, so SUS which is stainless steel for bearings is required.
Martensitic stainless steel such as 440C can be used. Further, in the case of an application that requires particularly high corrosion resistance, it is possible to use austenitic stainless steel such as SUS304 and SUS316.

Further, using the above stainless steel bearing steel as a base material, rust prevention such as zinc phosphate film forming treatment, manganese phosphate film forming treatment, tin phosphate film forming treatment, zinc dust chromium oxide conversion film forming treatment, etc. Treatment or rustproofing such as electroless nickel plating or chrome plating may be applied. One of these various rust preventive treatments may be applied alone, or a plurality of treatments may be used in combination.

Suitable electroless nickel plating is, for example, catalytic nickel plating method, Kanigen or Kanigen (registered name, GATC Company). Alternatively, composite electroless nickel plating may be used in which fine powders of ceramics such as silicon carbide, boron nitride, and silicon nitride are deposited and compounded in the electroless nickel plating film.

Further, instead of the composite electroless nickel plating in which the fine powder of ceramics is deposited and composited, a ceramic coating may be applied to directly coat the base material surface with the ceramics. Furthermore, if cost-effectiveness can be expected, at least one of the inner ring, the outer ring, and the rolling elements can be made of ceramics such as silicon nitride.

Next, the lubricating oil-containing polymer with which the rolling bearing of the present invention is filled will be described. As the polymer containing the lubricating oil of the present invention, one selected from the group of poly α-olefin polymers having basically the same chemical structure such as polyethylene, polypropylene, polybutylene, and polymethylpentene is used alone or in combination. be able to.

The above-mentioned groups of polymers which can be used in the present invention have the same basic structure but differ only in their average molecular weight. The average molecular weight used in the present invention is 1 × 10 5.
Those with relatively low molecular weight of ³ to 1 × 10 ⁶ and 1 × 1
Some of them have a high molecular weight of 0 ^{6 to} 5 × 10 ⁶ , and the former preferably has an average molecular weight of 1 × 10 ^{3 to} 5 × 10 ⁵ .

In the present invention, these low molecular weight polymers and high molecular weight polymers are used alone or in admixture as necessary. The ratio of all polymer components in the lubricating oil-containing polymer used, that is, the total amount of polymer added is 5 to 90% by weight, preferably 10 to 50% by weight, and the balance is the lubricating oil described below. If the amount of the polymer added is less than 5% by weight, the life of the rolling bearing filled with the polymer will be limited, that is, from the start of use to the occurrence of damage due to rolling fatigue such as cracks in either the bearing ring or the rolling elements. The rotational speed as well as the structural strength of the lubricating oil-containing polymer will fall below the levels normally required for bearings. In particular, with regard to securing the strength of the lubricating oil-containing polymer, the lower limit of the amount of polymer added is more preferably 10% by weight or more, because the amount of polymer added is greatly affected.

On the other hand, when the amount of the polymer added exceeds 90% by weight, the remaining lubricating oil amount becomes 10% by weight or less, so that a sufficient lubrication effect for the rolling bearing cannot be obtained and the life of the rolling bearing is shortened. In addition, the dynamic friction torque during rotation of the bearing becomes high. Particularly in terms of reducing the dynamic friction torque, the amount of the lubricating oil in the polymer containing the lubricating oil to be added has a large effect, and therefore the upper limit of the amount of the polymer added is lower in order to secure the required amount of lubricating oil.
It is preferably 0% by weight or less.

In the present invention, when the low molecular weight polymer and the high molecular weight polymer in the above-mentioned polymers are mixed and used, the compounding ratio of the low molecular weight polymer: high molecular weight polymer is 8: 2 to 1: 9. It should be in the range. In the blending of both the above polymers, if the low molecular weight polymer is less than 10% of the total polymer, the amount of the low molecular weight polymer having a large ability to retain the lubricating oil inside the polymer is too small, and therefore, it is retained in the polymer. The lubricating oil that should have been discharged from the polymer early during bearing operation. As a result, the replenishment of the lubricating oil to the bearing is interrupted during operation, and the life of the rolling bearing is shortened. Further, in the production process of the lubricating oil-containing polymer of the present invention,
It is difficult to uniformly mix the lubricant with the high-molecular weight polymer alone.

On the other hand, in the case of blending the above high and low polymers, when the low molecular weight polymer exceeds 80% of the total polymer, the strength as a structural body is higher in the high molecular weight polymer, and therefore the rolling bearing filled with this polymer. At the same time that the strength of the lubricating oil-containing polymer is insufficient, the bearing life is also shortened.
As the polymer containing the lubricating oil of the present invention, in addition to the above-mentioned poly α-olefin-based polymer, in order to improve the mechanical strength of the lubricating oil-containing polymer, the following thermoplastic resin and thermosetting resin are used. You may add.

As the thermoplastic resin, various resins such as polyamide, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, polyether sulfone, polyether ether ketone, polyamide imide, polystyrene and ABS resin can be used. As the thermosetting resin, unsaturated polyester resin, urea resin, melamine resin, phenol resin, polyimide resin,
Each resin such as an epoxy resin can be used.

These resins may be used alone or as a mixture. Furthermore, in order to disperse the poly α-olefin-based polymer and the other resin in a more uniform state,
If necessary, a suitable compatibilizer may be added. The lubricating oil used in the lubricating oil-containing polymer of the present invention includes poly α
-Paraffin hydrocarbon oils such as olefin oils, naphthene hydrocarbon oils, mineral oils, ether oils such as dialkyldiphenyl ether oils, ester oils such as phthalic acid esters / trimellitic acid esters, etc. are suitable. In addition, antioxidant, rust inhibitor, anti-wear agent,
You may use what added various additives, such as a defoaming agent and an extreme pressure agent.

The above-mentioned lubricating oil used in the present invention may be added with a trace amount of a fluorine-based surface-active substance. The above fluorine-based surfactant, as is basically shown in FIG. 1, a portion having in its molecular structure, the organophilic consisting hydrocarbon chains such as "~CH ₂ CH ₂ CH _2" ( _RH )
And a fluorine-based nonionic surfactant having a structure in which an organicphobic part (R _F ) composed of a fluorocarbon chain such as “CF ₃ CF ₂ CF ₂ —” coexists. It is an oligomer or a resin. Note that FIG. 1 (a) schematically shows the structure in the case of a chain molecule, and FIG. 1 (b) schematically shows the structure in the case of an oligomer or a resin.

The portion of the fluorocarbon chain (R _F ) contains, for example, a fluorophenylene group, a fluoroether group, a fluoroalkyl group, a perfluoroalkyl group, a perfluoropolyether group as a main component, and most commonly It is composed of a perfluoroalkyl group, and the carbon number is suitably in the range of 1-18. A carbon number of 1 is the minimum number required for the fluorocarbon to be oriented on the surface of the lubricating oil. On the other hand, carbon number is 1
When it exceeds 8, the solubility in hydrocarbon-based oil deteriorates.

The portion of the hydrocarbon chain (R _H ) is a saturated or unsaturated hydrocarbon chain having 5 to 18 carbon atoms. In particular,
Any of ethylene oxide group, vinyl group, amino group, ester group, epoxy group, acrylate group, ether group, methyl siloxane group, dimethyl siloxane group,
Those containing about 5 to 25 added moles can be suitably used in the present invention.

When this fluorinated surface-active substance is mixed in the lubricating oil, the portion having the hydrocarbon chain ( _RH ) remains in the oil due to its hydrophilicity. On the other hand, fluorocarbon chains (R
_The portion having _F ) is extruded out of the oil surface due to its phobicity and arranged in a certain direction, and is oriented and adsorbed at the interface C between the lubricating oil A and the outside B in the state shown in FIG. The oil interface C is covered with a portion R _F having phobicity.

That is, when the above-mentioned fluorine-based surface-active substance is added to the lubricating oil, even if it is a hydrocarbon-based oil, the contact interface with the outside world will appear as if it were a fluorine-based oil. As shown in FIG. Therefore, if the external environment is, for example, water, the exudation of lubricating oil into the water is suppressed, and at the same time, excessive exudation to the metal surface of the bearing component is suppressed, and as a result, the rolling bearing in water is suppressed. It is possible to maintain the function of for a longer time.

Specific examples of the above-mentioned fluorine-based surface-active substance include perfluoroalkylethylene oxide adduct [F-142] having a structure represented by the following chemical formula 1.
D (DIC Corporation)] can be preferably used.

[0029]

[Chemical 1]

Further, fluoroalkyl ester, perfluoroalkyl ester, fluoroalkyl ethylene oxide adduct, perfluoroalkyl amine oxide adduct, perfluoroalkyl oligomer, perfluoroacrylate-containing oligomer, or perfluoroalkyl group / parent Oily group-containing urethane or the like is used.

The amount of the fluorine-containing surface-active substance of the present invention added to the lubricating oil varies depending on the adsorption property (or the amount of adsorption) of the lubricating oil, but it is 0.01 to 0.1 wt% to achieve the intended purpose. be able to. The added amount can be adjusted depending on the usage conditions of the lubricating oil and the like. For example, if it is added in excess of the saturated adsorption amount, the amount that is excessively added and dispersed inside the lubricating oil is replenished to the lubricating oil surface, so even under conditions where the surface-active fluorine-containing substance may be exhausted, Can be used.

The critical significance of the amount of the above-mentioned fluorine-containing surface-active substance added to the lubricating oil is as follows. Addition amount is 0.01wt
If the rolling bearing is used underwater,
The effect of suppressing the seepage of the lubricating oil into water and the excessive seepage from the polymer cannot be obtained. On the other hand,
If it exceeds 0.1 wt%, the excess amount will be separated and precipitated in water, and the effect cannot be expected to be improved by further addition, which is meaningless. However, there is no particular adverse effect due to separation and precipitation in water.

The above-mentioned lubricating oil-containing polymer is filled in the bearing internal space other than the space occupied by the inner ring, the outer ring, the rolling elements and the cage when the corrosion resistant rolling bearing of the present invention is manufactured.
Further, by filling the inner space of the bearing other than the space occupied by the inner ring, the outer ring, and the rolling elements from which the cage is removed, it is possible to make the lubricating oil-containing polymer also serve as the cage. In this way, rolling bearings that use a polymer containing lubricant as a cage also do not come into contact with the rolling elements as in the case of rolling bearings equipped with general cages, so they can be used for a long time. Even if it does, cracks and peeling due to the contact between the cage and the rolling elements do not occur. Therefore, it is possible to expect an even longer life of the rolling bearing.

The main points of the method for filling the lubricating oil-containing polymer in the rolling bearing of the present invention will be described below. When the lubricating oil-containing polymer is filled, it is preferable to keep the plurality of rolling elements in the rolling bearing at equal intervals.
Generally, the cage performs its function, but in that case, if the cage is made of corrosion-resistant metal, there is no problem, but if it is made of plastics, holding using a plastic with a melting point higher than the melting point of the lubricating oil-containing polymer is used. It needs to be a bowl. This is because the lubricating oil-containing polymer is filled in a molten state, so that the plastic cage is prevented from melting.

However, as described above, in order to extend the life of the rolling bearing, when a general cage is not used but a polymer containing lubricating oil is used also as a cage, it is shown in FIGS. It is advisable to use such a jig to keep the rolling elements at equal intervals in the circumferential direction. FIG. 3 shows the case of a radial rolling bearing. In this case, according to the number of rolling elements 1, a rolling bearing 4 is mounted on a jig 3 provided with spherical seats 2 at equal intervals on the circumference.
The bearing 4 with the rolling elements 1 held at equal intervals.
A lubricating oil-containing polymer is filled in the inside of the bearing, which is melted by heating and uniformly impregnated into the space inside the bearing, and then cooled and solidified.

FIG. 4 shows the case of a thrust bearing. In this case, the rolling element 1 is circumscribed on the ring-shaped inner jig 6. A split type outer jig 7 is arranged on the outer periphery of the rolling element 1. The outer jig 7 is provided with spherical seats 8 on its inner peripheral surface at equal circumferential intervals, and the rolling bodies 1 of the thrust bearing are positioned and held on the spherical seats 8 respectively. Fill the polymer containing the lubricating oil in the same manner as in.

However, as for the above jig, as long as it has a structure capable of preventing the rolling elements from moving at the time of filling the lubricating oil-containing polymer and ensuring a sufficient filling space for the lubricating oil-containing polymer in the bearing, it is as shown in the drawing. However, different ones may be used. In the filling process of the polymer containing lubricating oil,
Care must be taken that the temperature of the rolling bearing does not exceed the tempering temperature of the bearing. Specifically, 160 to 17
Keep below 0 ° C.

In the step of filling the lubricating oil-containing polymer as described above, pressure may be applied at an appropriate pressure during cooling and solidification. Injection molding may be used together when the lubricating oil-containing polymer is filled.

[0039]

EXAMPLES Examples of the present invention will be given below. (Embodiment 1) FIG. 5 is an embodiment in the case of being applied to a radial ball bearing which is a corrosion resistant rolling bearing.
An inner ring 12, a plurality of rolling elements (balls) 13 interposed therebetween, and a cage 14 that holds the rolling elements 13 at equal intervals around the circumference, and the outer ring 11 and the inner ring 12 thereof. The space between the rolling elements 13 and the cage 14 is filled with the lubricating oil-containing polymer 15 in the space sandwiched between the two.

The outer ring 11, the inner ring 12, the rolling elements 13, and the cage 14 are all made of stainless steel SUS440C, which is a material having excellent corrosion resistance. The lubricating oil-containing polymer 15 contains 80% by weight of paraffinic hydrocarbon oil with respect to 20% by weight of a polyethylene polymer composed of 14% by weight of low molecular weight polyethylene and 6% by weight of ultrahigh molecular weight polyethylene. .

The low molecular weight polyethylene has an average molecular weight of 1 × 10 ^{3 to} 5 × 10 ⁵ , and the ultrahigh molecular weight polyethylene has an average molecular weight of 1 × 10 ^{6 to} 5 × 10 ^6.
Is. In the case of this example, the filling of the lubricating oil-containing polymer 15 into the rolling bearing internal space was carried out by the following procedure.

First step: 80 g of paraffinic hydrocarbon oil as a lubricating oil and 8 g of low molecular weight polyethylene, which is one component of the polymer, are mixed and the mixture is placed in an oil bath for 16
Heat to 0 ° C. and evenly dissolve both while stirring. Second step: The thus obtained uniform solution is allowed to cool, and then 6 g of low molecular weight polyethylene and 6 g of ultra high molecular weight polyethylene are added thereto. Then, using a mixer, mix thoroughly until the whole becomes creamy. The resulting creamy mixture is the base lubricating oil containing polyethylene.

Here, the required amount (14 g) of the total low molecular weight polyethylene was not added to the ultra high molecular weight polyethylene from the beginning, but a half amount (8 g) was first mixed with the paraffinic hydrocarbon oil and dissolved by heating. The reason why the procedure is adopted is that when it is added to the ultra-high molecular weight polyethylene from the beginning, the viscosity at the time of dissolution becomes too high and it is impossible to uniformly mix and dissolve it.

Third step: The above-mentioned cream-like polyethylene containing a base lubricating oil is filled in the space between the outer ring 11 and the inner ring 12 of the rolling bearing. After filling, cover both ends of the rolling bearing with metal flat plates,
It is heated to 160 to 170 ° C. in an oven to melt the filled polyethylene containing the base lubricating oil.

By this melting, the filled cream-like base lubricant oil-containing polyethylene becomes liquid, and as a result, it can flow into every corner of the narrow space between the component parts of the ball bearing. Fourth step: After that, with both end faces of the rolling bearing being covered with metal flat plates, the rolling bearing is transferred to a water-cooled press and rapidly cooled while being pressurized.

As a result, the polyethylene containing the base lubricating oil, which had been melted in the bearing space, is solidified and the filling operation is completed. (Embodiment 2) This embodiment is also applied to a radial ball bearing which is a corrosion-resistant rolling bearing as in Embodiment 1, and similarly as shown in FIG. 5, an outer ring 11, an inner ring 12 and an intervening member therebetween. A plurality of rolling elements 13 and the rolling elements 1
3 is provided with cages 14 for holding the circles at equal intervals, and in the space between the outer ring 11 and the inner ring 12, the lubricating oil is contained in the space other than the positions occupied by the rolling elements 13 and the cages 14. It is filled with polymer 15. Further, in the case of this embodiment, although not shown, a seal (Z seal) for sealing the inside of the bearing is fixed and attached to the end faces of the outer ring 11 and the inner ring 12.

Among the above-mentioned bearing components, the outer ring 11, the inner ring 12, the cage 14 and the Z seal are all made of stainless steel SUS440C which is a material having excellent corrosion resistance. On the other hand, the rolling element 13 is made of Si, which is a material excellent in corrosion resistance.
It is made of ₃ N ₄ . In addition, the lubricating oil-containing polymer 15 has a poly-α-olefin-based polymer and an average molecular weight of 1 ×.
It is a mixture of 10% by weight of 10 ³ to 1 × 10 ⁶ polyethylene and 5% by weight of polypropylene having an average molecular weight of 1 × 10 ^{6 to} 5 × 10 ⁶ , and the lubricating oil contained in this polymer is a dialkyldiphenyl ether oil. 85% by weight was used.

The filling of the lubricating oil-containing polymer 15 into the internal space of the ball bearing in the case of Example 2 was carried out according to the first to fourth steps of the procedure of Example 1. (Example 3) In this example, a corrosion-resistant rolling bearing is used.
This is the case when applied to a radial roller bearing (not shown).

That is, the rolling element 13 in the bearing shown in FIG. 5 is not a ball but a cylindrical roller.
An outer ring, an inner ring, a plurality of rolling elements interposed between them, cylindrical rollers, and a cage for holding these rolling elements at equal intervals around the circumference, and a space sandwiched between the outer ring and the inner ring. A space other than the space occupied by the rolling elements and the cage is filled with the lubricating oil-containing polymer.

Among the above-mentioned bearing components, the outer ring, the inner ring, the cylindrical rollers of the rolling elements, and the cage are all made of stainless steel SUS440C, which is a material having excellent corrosion resistance, and the surface thereof is further electroless nickel plated. Is applied. Further, the lubricating oil-containing polymer has an average molecular weight of 1 × 10 ^{6 to} 5 × 10 ⁶ in which the polymer is a poly-α-olefin type.
⁶ % polypropylene 5% by weight, the lubricating oil contained in this polymer is naphthene hydrocarbon oil 75% by weight
Is used. Two types of polypropylene may be selected within the above range of the average molecular weight for the filling step of the polymer containing the lubricating oil.

The filling of the above-mentioned lubricating oil-containing polymer into the roller bearing internal space in the case of Example 3 was also carried out according to the first to fourth steps of the procedure of Example 1. (Example 4) In this example, a corrosion-resistant rolling bearing is used.
This is the case when applied to thrust ball bearings.

That is, the thrust ball bearing 20 shown in FIG.
In, the outer ring (fixed ring) 21 and the inner ring (rotating ring) 22
And a plurality of balls 23, which are rolling elements interposed at equal intervals around the circumference, in a space sandwiched between the outer ring 21 and the inner ring 22 of the ball, other than the space occupied by the rolling elements 23. Is filled with the lubricating oil-containing polymer 25. In the illustrated example, the cage is not provided, and the lubricating oil-containing polymer 25 also serves as the cage.

Of the above-mentioned bearing components, the outer ring 21, the inner ring 22 and the balls 23 of the rolling elements are all made of stainless steel SUS440C which is a material having excellent corrosion resistance. The lubricating oil-containing polymer 25 has an average molecular weight of 1 × 10 ^{3 to} 5 × 10 ^{5 in which the} polymer is a poly-α-olefin type.
14% by weight of low molecular weight polyethylene and an average molecular weight of 1 ×
10 ^{6 to} 5 × 10 ⁶ ultra high molecular weight polyethylene 6% by weight
On the other hand, 80% by weight of paraffinic hydrocarbon oil was used as the lubricating oil contained in this polymer.

Thrust ball bearing 20 according to the fourth embodiment
The filling of the lubricating oil-containing polymer 25 into the internal space of the
The procedure was performed according to the first to fourth steps of the procedure of Example 1. The rolling elements 23 of the thrust bearing of the fourth embodiment may be rollers instead of balls. Further, the thrust bearing of Example 4 does not have a retainer, and the polymer 25 containing the lubricating oil also has the function of the retainer, but the present invention is not limited to this, and the rolling element 23 is equally divided into the circumference of the retainer. It may be held by.

A seal may be attached to the thrust bearing. In this case, the material of the seal is preferably stainless steel having corrosion resistance. In addition, the rolling element 23
Has been described as being made of stainless steel, but other materials having excellent corrosion resistance, for example, ceramics such as Si ₃ N ₄ may be used.

Also in the thrust bearing of the fourth embodiment, the outer ring 21, the inner ring 22 and the rolling elements 23 may be subjected to surface treatment for corrosion prevention such as electroless nickel plating. (Example 5) In this example, the corrosion resistance and rolling resistance of the corrosion resistant rolling bearing to which the present invention was applied was tested.

As the test object, a thrust ball bearing 20 of the same type as shown in FIG. 6 was used. However, the materials of the bearing rings (outer ring 21, inner ring 22) and rolling elements (balls) 23, which are bearing components, and the material of the cage were the combinations shown in Table 1. As for the cages, all of the cages according to the present invention were of the type in which the lubricating oil-containing polymer was also used, while the comparative examples also included those having PTFE cages.

[0058]

[Table 1]

In this test, the corrosion resistance to water was tested, and the rolling bearing 20 of the test object was operated in water to measure the operating time (life) until cracking. The test device is shown in FIG. The container 31, which also serves as a mount for the device under test 20, is designed so that the water flowing from the inlet 32 at the bottom continuously flows out from the outlet 33 at the upper part, and the bearing 20 for the device under test is placed at the center of the container bottom. A mounting surface 34 is provided. The outer ring (fixed ring) 21 of the bearing 20 under test is fixed to the mounting surface 34. The rotary shaft 35 is inserted into the container 31 from above and fitted into the inner ring (rotary ring) 22 of the bearing 20 under test, and the rotary shaft 35 is rotated to drive the bearing 20 under test.

The lower surface of the container 31 is supported by a load device 36 arranged coaxially with the rotating shaft 35 via balls 37, and a load F is applied. In addition, a load cell 39 is provided on the side surface of the container 31 via a cantilever 38 fixed to the container.
Is attached to measure the dynamic torque of the bearing 20 under test. Further, the water temperature of the container 31 is controlled to measure the heat distortion temperature of the lubricant-containing polymer 25 filled in the bearing 20 to be tested, and from the result, the strength when the lubricant-containing polymer is also used as a cage material Was evaluated.

Further, with respect to the lubricant-containing polymer to which the fluorine-based surface-active substance was added, the presence or absence of separation and precipitation was measured. The test conditions are as follows. Test object bearing 20: Thrust ball bearing, 6 balls, Model # 51305 Load device load F: 180 kgf Rotation speed: 1500 rpm The results of this durability test are shown in Table 2.

[0062]

[Table 2]

(Note 1) The polyethylene compounding ratio of the polymer is as follows. Weight ratio of low molecular weight polyethylene to ultra high molecular weight polyethylene (average molecular weight 1 x 10 ^{3 to} 5 x 10 ⁵ ) (average molecular weight 1 x 10
^{6 ~5} × 10 ⁶⁾ (Note 2) Fluorine-based surface-active substances are, perfluoroalkyl ethylene oxide adducts.

(Note 3) Dynamic torque of 1.5 kg · cm or less is marked with ⊚, 1.5 to 2 kg · cm is marked with ◯, and torque exceeding 2 kg · cm is marked with x. (Note 4) The heat distortion temperature that can be used as a cage is 60 ° C.
The above was marked with ⊚, 50 to 60 ° C was marked with ◯, and 50 ° C or lower was marked with x.

From the results shown in Table 2, the following was clarified. The corrosion-resistant rolling bearing of the present invention has a much longer life than that of the comparative example, has a low dynamic torque, and guarantees the excellent lubrication performance of the lubricating oil-containing polymer. Further, the strength for the lubricant-containing polymer to function as a cage is practically sufficient. However, Example 4 of the present invention, in which the blending ratio of low-molecular-weight polyethylene is large (80%), is lower in strength and shorter in life than the others. Further, in Invention Example 11 in which the total content of the polymers is as high as 90% by weight, the dynamic torque is high and the life is short.

When the amount of the fluorine-containing surface active substance added is 0.15% by weight, precipitation of the fluorine-containing substance is observed. From this, it can be said that the addition amount is preferably less than 0.15% by weight. In Comparative Example 1, the polymer content in the lubricant oil-containing polymer was as low as 3% by weight, the life before cracking when used as a bearing was short, and the strength was also greatly reduced. On the contrary, in Comparative Example 2, the polymer content was as high as 95% by weight, and the amount of lubricating oil was relatively insufficient and the life until cracking was shortened. Moreover, the dynamic torque is excessive.

In Comparative Example 3, the blending ratio of low-molecular-weight polyethylene in the polymer is too small, and the lubricating oil retention capacity is insufficient, resulting in a shorter life. On the contrary, in Comparative Example 4, the blending ratio of the low molecular weight polyethylene in the polymer is too large, the strength is insufficient, and the life is also short. Comparative Example 5 was equipped with a cage made of PTFE, and no lubricating oil-containing polymer was used. In this case, the PTFE material of the cage is peeled off from the surface of the rolling element in a short time when used in water, and the life before cracking is the shortest in all the samples, which is less than half that of the present invention.

[0068]

As described above, the corrosion-resistant rolling bearing of the present invention is provided with the corrosion-resistant outer ring, inner ring, and rolling element, and the space between the outer ring and the inner ring is filled with the lubricating oil-containing polymer. The lubricating oil-containing polymer contains one or more polymers selected from the group of different polymers having basically the same chemical structure, and the total content of the polymers in the lubricating oil-containing polymer is 5 to 90% by weight
Therefore, the balance consists of lubricating oil. Therefore, the following effects can be obtained.

It has a long life. When the bearing is operated, the lubricating oil contained in the lubricating oil-containing polymer gradually exudes over time and is evenly distributed to the contact surface between the bearing ring and the rolling elements, thus Good lubrication is performed for a long time to prevent seizure and cracking of the rolling bearing.

A long life is guaranteed even in water or in a corrosive gas atmosphere. Since the outer ring, inner ring, and rolling element surfaces made of a corrosion-resistant material are further covered with a polymer containing lubricating oil to be shielded from the outside, the inside of the bearing is protected from the corrosive atmosphere even when used in a special environment. Low cost.

The lubricating oil can be automatically supplied stably for a long period of time without using expensive ceramics, and the generation of rust or the like is suppressed even in a corrosive atmosphere such as water, so that the cost is low. .

[Brief description of drawings]

FIG. 1 is a diagram schematically showing the structure of a fluorine-based surface-active substance added to a lubricating oil of the present invention. FIG. 1 (a) shows a chain molecule, and FIG. 1 (b) shows an oligomer or a resin. Each case is shown.

FIG. 2 is a diagram schematically showing a state in which the surface of a lubricating oil is coated with the fluorine-based surface-active substance of the present invention.

FIG. 3 is a cross-sectional view illustrating a usage mode of a jig used for filling a radial bearing of the present invention with a polymer containing lubricating oil.

FIG. 4 is a cross-sectional view illustrating a usage mode of a jig used for filling a thrust oil bearing polymer of the present invention with a lubricating oil-containing polymer.

FIG. 5 is a half sectional view of an embodiment in which the present invention is applied to a radial ball bearing.

FIG. 6 is a half sectional view of an embodiment when the present invention is applied to a thrust ball bearing.

FIG. 7 is a cross-sectional view of an endurance test device for operating a thrust ball bearing in water to measure an operating time (life) until cracking.

[Explanation of symbols]

 11 Outer ring 12 Inner ring 13 Rolling element 14 Cage 15 Lubricating oil-containing polymer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 107: 04) C10N 30:12 40:02

Claims (1)

[Claims] 1. A corrosion-resistant outer ring, an inner ring and a rolling element are provided, and a lubricating oil-containing polymer is filled in a space sandwiched between the outer ring and the inner ring, and the lubricating oil-containing polymer is selected from a group of different polymers. A corrosion-resistant rolling bearing comprising one or more selected polymers, wherein the total content of the polymers in the lubricating oil-containing polymer is 5 to 90% by weight, and the balance is lubricating oil.