JP2009036221A - High-speed rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed rolling bearing which can sufficiently cope with high-speed rotation having a dmN value of 1.7 million or larger which is a product of, for example, a pitch circle diameter dm (mm) and the number of revolutions N (rpm) even if a grease sealing amount is small, allows the compactness of a machine tool or the like, and can reduce an operation expense. <P>SOLUTION: The high-speed rolling bearing 1 comprises an inner ring 2, an outer ring 3, a plurality of rolling bodies 4, a cage 5 having a recess chamfered at its edge, and a seal member 6 for covering an opening of a clearance between the inner and the outer rings, and grease is sealed into the circumference of the rolling bodies 4. The dynamic viscosity (40°C) of the base oil of the grease is 15 to 30 mm<SP>2</SP>/sec, an urea-based incremental agent which is obtained by making a prescribed isocyanate component react with a monoamine component is used in the grease, and the urea-based incremental agent is compounded to the grease at not lower than 3 wt.% and lower than 9 wt.% as a whole. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-speed rolling bearing that supports a high-speed rotation shaft such as a machine tool spindle (spindle).

The main spindle of the machine tool is preferably one that rotates at a high speed in order to increase machining efficiency, and various lubrication techniques are applied to the bearings. As a lubrication method suitable for the spindle rotating at high speed, for example, methods such as oil mist lubrication, air-oil lubrication, and jet lubrication are known.
However, such a lubrication method requires ancillary equipment such as compressed air and an oil supply device, which is one of the causes of increasing the initial cost and running cost of machine tools. It can be said that this is a preferable lubrication method with less maintenance. For example, examples of the high-speed rolling bearing that supports a rotating shaft that rotates at a high speed of 2000 to 8000 rpm or higher include an angular ball bearing and a cylindrical roller bearing that support a machine tool spindle (spindle).

As shown in FIG. 5, the angular ball bearing 21 can apply an axial load from one direction in addition to a radial load, and a straight line connecting the contact points of the steel ball 24 with the inner ring 22 and the outer ring 23 is formed. It has an angle (contact angle) α with respect to the radial direction. Grease is enclosed in a bearing space formed by the inner ring 22, the outer ring 23, and the steel ball 24.
Lubricant used in high-speed rolling bearings such as angular ball bearings and cylindrical roller bearings should be lubricated with a grease adjusted to a consistency that does not require any lubrication and does not pollute the surrounding environment. Is preferred.

The following summarizes the lubrication characteristics and problems required for grease for high-speed rolling bearings such as spindle rolling bearings.
(A) In order to extend the lubrication life of a long-life rolling bearing as much as possible, lubricant (grease or its base oil) is supplied from the rolling bearing as described in (i) to (iii) below. It is necessary that it is difficult to leak, has excellent heat resistance of grease, and can form an oil film thickness necessary for lubrication.

(I) When rolling bearings are operated at high speeds, the grease in the rolling bearings or grease flows out of the bearings due to centrifugal force, or the base oil in the grease separates and flows out, which makes a significant contribution to lubrication. It is difficult to stay in the vicinity and is prone to poor lubrication. In order to prevent such a situation, a seal member such as a shield plate is attached to the rolling bearing. However, depending on the structure of the bearing, it may not be possible to attach the seal member. In some cases, the lubricant cannot be completely sealed.
In the case of a rolling bearing that is not operated at a high speed, excess grease that is pushed out from the frictional part due to the motion of the rolling elements and the cage may recirculate to some extent inside the bearing and contribute to lubrication again depending on the rotation conditions. However, in a rolling shaft support rolling bearing such as a machine tool that rotates at a high speed, the wind pressure generated inside the bearing prevents this recirculation, and therefore it is difficult for grease to be supplied to the rolling part, and poor lubrication is likely to occur. For this reason, in rolling bearings rotating at high speed, only a small amount of grease contributes to lubrication, and the properties of the grease are particularly important. Further, the grease used for the high-speed rolling bearing needs to maintain the lubricating performance even with a small amount of grease.

(ii) When the operating conditions are increased, the rolling surface of the bearing locally generates heat and becomes high temperature. At this time, the grease with poor heat resistance is thermally deteriorated, and the life of the grease is remarkably shortened. For such problems, attempts have been made to use heat-resistant thickeners and base oils, or to add antioxidants. However, these attempts have not led to a sufficient improvement in durability.
(iii) Conventional grease with improved lubricity (oil film thickness) increases shear friction resistance and increases rotational torque and heat generation when base oil viscosity is increased. The base oil viscosity is kept low. For this reason, the oil film of the lubricating oil that has become low viscosity due to a temperature rise accompanying high speed may become thin and cause sliding wear.

  (B) Low torque (inhibition of temperature rise) Existing high-speed bearing grease keeps the base oil viscosity low as described above, but when the bearing rotates at high speed, the viscosity increases due to temperature rise. There is a problem that the oil film is remarkably lowered and an oil film having a thickness necessary for lubrication cannot be formed.

  (C) The low vibration grease may increase the vibration of the bearing depending on the type of thickener. That is, with a grease containing a thickener that forms large and hard aggregates, the vibration of the rolling bearing to be lubricated becomes large.

As described above, when the conventional grease is used for a high-speed rolling bearing, there is a problem that the required physical properties such as long life, low torque and low vibration cannot be satisfied. As a countermeasure, a grease containing a urea compound has been proposed (see Patent Documents 1 to 3), but the oil consumption is increased, which is insufficient to obtain higher speed performance.
For example, Patent Document 3 discloses that a base oil having a kinematic viscosity at 40 ° C. of 15 mm ² / sec or more and 40 mm ² / sec or less and a content of 9 mass% or more and 14 mass% or less of the entire grease composition. A grease composition containing a diurea compound thickener and having a miscibility of 220 to 320 is disclosed.
However, even in the above grease composition, it is difficult to reduce the amount of thickener blended and reduce the amount of grease filled, it can sufficiently cope with high-speed rotation of the bearing, make machine tools compact and reduce operating costs It is difficult to make it possible.
In recent years, rolling bearings have been used more and more severely, and the rolling for spindles used at high-speed rotation with a dmN value, which is the product of pitch circle diameter dm (mm) and rotation speed N (rpm), is 1.7 million or more. The number of bearings is increasing. As the rotational speed of the bearing increases, it is difficult to satisfy all the performance required for the bearing with existing grease.
Japanese Patent Laid-Open No. 2000-169872 JP 2003-83341 A JP 2006-29473 A

  The present invention has been made in view of such a situation. Even if the amount of grease is small, for example, the dmN value, which is the product of the pitch circle diameter dm (mm) and the rotational speed N (rpm), is 1.7 million. The purpose is to provide a high-speed rolling bearing that can sufficiently cope with the above-mentioned high-speed rotation, and that can reduce the size of machine tools and the like and reduce operating costs.

  The high-speed rolling bearing of the present invention is a high-speed rolling bearing that supports a shaft that rotates at high speed. The rolling bearing includes an inner ring, an outer ring, and a plurality of rolling elements interposed between the inner and outer rings, A cage that holds the rolling elements, and a seal member that covers the opening of the gap between the inner and outer rings, the cage has a recess on the inner surface of the pocket portion, and at least the edge of the recess is chamfered; A grease is sealed around the rolling element. In particular, the concave portion is an oil reservoir portion or a dull portion.

Further, the grease comprises a base oil and a urea thickener, the base oil has a kinematic viscosity at 40 ° C. is ^{15 mm 2 / sec~30 mm 2 /} sec, the urea thickener Is obtained by reacting a polyisocyanate component with a monoamine component, and the monoamine component contains at least one monoamine selected from an aliphatic monoamine and an alicyclic monoamine in an amount of 50 mol% or more based on the total monoamine. The above-mentioned urea-based thickener is blended in an amount of 3 wt% to less than 9 wt% with respect to the entire grease.

The base oil has a surface tension of 25 mN / m or more and a density of 0.95 g / cm ³ or less.
The base oil is at least one oil selected from a synthetic hydrocarbon oil, an ester oil, and an alkyl diphenyl ether oil.

  The cage is a resin cage. The resin used for the cage is a polyamide (hereinafter referred to as PA) resin, a phenol resin or a polyetheretherketone (hereinafter referred to as PEEK) resin.

  The high-speed rolling bearing is a bearing that supports a main shaft of a machine tool. Further, the bearing is an angular ball bearing or a cylindrical roller bearing.

The high-speed rolling bearing according to the present invention includes a base oil whose kinematic viscosity at 40 ° C. is 15 to 30 mm ² / sec and a predetermined urea-based thickener of 3 wt% or more and less than 9 wt%. Since it is a blended product, even if a small amount of grease is filled, the oil supply capability to the raceway surface is excellent under high-speed rotation while maintaining load resistance.
In particular, the monoamine component of the urea thickener contains at least one monoamine selected from aliphatic monoamines and alicyclic monoamines in an amount of 50 mol% or more based on the total monoamines. The oil in the grease can be stably supplied to the rolling surface due to the capillary phenomenon of the thickener fiber without being easily broken by force.

  The high-speed rolling bearing of the present invention encloses the above grease, so that grease does not flow out of the bearing under a high centrifugal force load, and the amount of oil necessary for bearing lubrication is stably supplied for a long period of time, An oil film having a thickness required for lubrication is formed on the raceway surface that is in sliding contact with high speed. For this reason, the bearing durability life under high-speed rotation is improved.

  Furthermore, since there is a recess in the inner surface of the pocket portion of the cage, the grease held in the recess is also supplied to the contact portion between the rolling element and the inner surface of the pocket portion during bearing operation, and the lubrication state of the contact portion is kept good. Can do. In addition, since at least the edge of the recess is chamfered, it is difficult for the grease attached to the surface of the rolling element to be scraped off by the edge, and the grease can be easily taken into the necessary portion of the pocket. As a result, the bearing durability life under high-speed rotation is dramatically improved.

The high-speed rolling bearing of the present invention is not particularly limited in terms of structure, and for example, an angular ball bearing 1 shown in FIG. 1 can be exemplified. FIG. 1 is a longitudinal sectional view showing a grease-filled angular ball bearing. FIG. 2 is a perspective view of a bran type cage 5 used for the angular ball bearing 1.
As shown in FIG. 1, the angular bearing 1 includes a bearing groove in which a rolling element 4 is held by a cage 5 between an inner ring 2 and an outer ring 3, and a locking groove provided on an inner peripheral surface of the outer ring 3. It is an angular ball bearing sealed with a sealing member 6 fixed to the. In a bearing space formed by the inner ring 2, the outer ring 3, and the rolling elements 4, grease 7 described later is enclosed. A straight line connecting the contact points of the rolling elements 4 with the inner ring 2 and the outer ring 3 has a contact angle β with respect to the radial direction, and can carry a radial load and an axial load in one direction. Moreover, the rolling element 4 can also be made from ceramics, such as silicon nitride and silicon carbide.

  Further, as shown in FIG. 2, a concave oil reservoir 5 c and a dull portion 5 b are provided on the pocket portion inner surface 5 a of the paddle type retainer 5. In addition, chamfering is performed on the edge portion 5d of the concave portion generated by providing these concave portions. Only one of the oil sump portion 5c and the loose portion 5b may be provided. Further, chamfering can be performed not only on the edge of the recess, but also on almost all edges that may come into contact with the rolling element in the cage.

A deep groove ball bearing can be exemplified as another embodiment of the high speed rolling bearing of the present invention. FIG. 3 is a longitudinal sectional view showing a grease-filled deep groove ball bearing. FIG. 4 is a perspective view of a crown type cage 5 used for a deep groove ball bearing.
As shown in FIG. 3, the deep groove ball bearing 11 has a bearing space in which a rolling element 14 is held by a cage 15 between an inner ring 12 and an outer ring 13. It is a deep groove ball bearing sealed with a seal member 16 fixed in the groove. In a bearing space formed by the inner ring 12, the outer ring 13, and the rolling elements 14, a later-described grease 17 is enclosed. Moreover, the rolling element 14 can also be made from ceramics, such as silicon nitride and silicon carbide.

  As shown in FIG. 4, a concave cross-surface side oil reservoir 15b and a bottom-side oil reservoir 15c are provided on the pocket portion inner surface 15a of the cage 15, and an edge portion 15d of the recess produced by providing these concave portions. Has been chamfered. Further, chamfering can be performed not only on the edge of the recess, but also on almost all edges that may come into contact with the rolling element in the cage.

The cage incorporated in the high-speed rolling bearing of the present invention is preferably made of resin. By using a resin cage and reducing the weight of the bearing, the influence of centrifugal force under high-speed rotation can be reduced. Further, frictional heat generation at the sliding portion between the rolling element and the cage can be suppressed.
It is preferable to use a resin having heat resistance and oil resistance for the resin cage. For example, PA resin, polyethylene resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polyphenylene sulfide resin, polyethersulfone resin, phenol resin, polyetherimide resin, polyamideimide resin, PEEK resin, thermoplastic A polyimide resin etc. can be illustrated suitably. These can be used alone or in combination of two or more.
Among these, PA resin, PA66 resin, PA9T resin, etc., which are light weight, excellent in oil compatibility and excellent in mechanical stability, are reinforced with glass fiber etc. PA resin, phenol resin such as bakelite, and PEEK resin are used. It is preferable.

  The high-speed rolling bearing of the present invention preferably contains 1% by volume or more and less than 10% by volume of the volume of the bearing gap. If it is less than 1% by volume, the amount of grease necessary for lubrication will be insufficient and will easily be depleted. If it is 10% by volume or more, torque due to agitation is large, heat generation is increased, lubrication life is not improved, cost is increased, and environment is not preferable.

  As the high-speed rolling bearing of the present invention, in addition to the angular ball bearing shown in FIG. 1 and the deep groove ball bearing shown in FIG. 3, cylindrical roller bearing, tapered roller bearing, self-aligning roller bearing, needle roller bearing, thrust cylindrical roller A bearing, a thrust tapered roller bearing, a thrust needle roller bearing, a thrust self-aligning roller bearing, or the like can also be used. Among them, it is preferable to use an angular ball bearing or a cylindrical roller bearing because it has both rotational accuracy at high speed and load bearing performance.

  The high-speed rolling bearing of the present invention is characterized by using a grease containing the following base oil and urea-based thickener in addition to forming an oil reservoir in the cage.

As the base oil of the grease that can be used in the present invention, a lubricating oil having a kinematic viscosity at 40 ° C. (hereinafter simply referred to as kinematic viscosity) of 15 to 30 mm ² / sec can be used. In particular, a lubricating oil having a kinematic viscosity of 15 to 25 mm ² / sec is preferable. When the kinematic viscosity is less than 15 mm ² / sec, the viscosity is too low to obtain sufficient load resistance. Also, if the kinematic viscosity exceeds 25 mm ² / sec, the oil supply to the raceway surface becomes insufficient with high-speed rotation, and the bearing life will be reached early.

As a kind of the lubricating oil, a synthetic hydrocarbon oil, an ester oil, an alkyl diphenyl ether oil, or a mixed oil thereof is preferable.
Further, it is preferable that the kinematic viscosities of synthetic hydrocarbon oil, ester oil, and alkyl diphenyl ether oil are 15 to 30 mm ² / sec. Even if it is a mixed oil as it is this range, the range of kinematic viscosity can be 15-30 mm < ² > / sec.
When using mixed oil, it is preferable to use a mixed oil of synthetic hydrocarbon oil and ester oil. The mixing ratio is preferably synthetic hydrocarbon oil / ester oil (mass ratio) = 8/2 to 2/8. In particular, the synthetic hydrocarbon oil is preferably equal to or more in mass ratio than the ester oil.
Alkyl diphenyl ether oil can be used alone.

Examples of the synthetic hydrocarbon oil include poly-α-olefins such as normal paraffin, isoparaffin, polybutene, polyisobutylene, 1-decene oligomer, 1-decene and ethylene co-oligomer.
Examples of ester oils include dibutyl sebacate, di-2-ethylhexyl sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl tartrate, methyl acetyl cinnolate, and the like, trioctyl trimellitate, trioctyl Aromatic ester oils such as decyl trimellitate and tetraoctyl pyromellitate, polyol ester oils such as trimethylolpropane caprylate, trimethylolpropane verargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol verargonate And carbonate ester oil.
Examples of the alkyl diphenyl ether oil include monoalkyl diphenyl ether, dialkyl diphenyl ether, and polyalkyl diphenyl ether.

The grease base oil that can be used in the present invention has a surface tension of 25 mN / m or more, preferably 27 to 40 mN / m, and a density of 0.95 g / cm ³ or less, preferably 0.8 to 0.93 g / cm ³ . is there. If the surface tension is less than 25 mN / m, it will be difficult to move to the rolling section due to capillary action, and it will not be possible to stably supply the required amount of oil at high speed, and if the density exceeds 0.95 g / cm ³ Due to the phenomenon, it is difficult to move to the rolling section, and the required amount of oil cannot be stably supplied at high speed.

The urea-based thickener for grease that can be used in the present invention is obtained by reacting a polyisocyanate component with a monoamine component.
Examples of the polyisocyanate component include phenylene diisocyanate, tolylene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate. Of these, aromatic diisocyanates are preferred.
Moreover, the polyisocyanate obtained by reaction with excess diisocyanate by molar ratio with respect to diamine and this diamine can be used. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, xylenediamine, and diaminodiphenylmethane.

The monoamine component is a monoamine component containing at least one monoamine selected from an aliphatic monoamine and an alicyclic monoamine in an amount of 50 mol% or more, preferably 80 mol% or more based on the total monoamine. By containing 50 mol% or more, it is not easily broken by the shearing force of the thickener under high speed, and the oil content in the grease can be stably supplied to the rolling surface by the capillary action of the thickener fiber. .
Examples of monoamines other than aliphatic monoamines and alicyclic monoamines include aromatic monoamines.
Examples of the aliphatic monoamine include hexylamine, octylamine, dodecylamine, hexadecylamine, octadecylamine, stearylamine, and oleylamine. Among these, octylamine is preferable.
Examples of the alicyclic monoamine include cyclohexylamine.
Examples of the aromatic monoamine include aniline and p-toluidine, and among these, p-toluidine is preferable.

  In the present invention, the urea-based thickener is contained in an amount of 3 to 9% by weight, preferably 5 to 9% by weight, based on the entire grease. If the blending amount is less than 3% by weight, the base oil retention capacity is not sufficient, and especially at the beginning of rotation, a large amount of oil is separated at one time and grease leakage occurs, resulting in a shortened bearing durability life. On the other hand, if the blending amount is 9% by weight or more, the amount of the base oil is relatively small, the oil supply ability is insufficient, the lubrication is insufficient early, and the bearing durability life is similarly shortened.

  In addition, the grease may contain known grease additives as necessary. Examples of the additives include antioxidants such as organic zinc compounds, amines, and phenolic compounds, metal deactivators such as benzotriazole, viscosity index improvers such as polymethacrylate and polystyrene, molybdenum disulfide, and graphite. Examples thereof include solid lubricants, metal sulfonates, antirust agents such as polyhydric alcohol esters, friction reducing agents such as organic molybdenum, oily agents such as esters and alcohols, and antiwear agents such as phosphorus compounds. These can be added alone or in combination of two or more. The content of these additives is preferably individually 0.05% by weight or more of the total amount of grease, and the total amount is preferably in the range of 0.15 to 10% by weight of the total amount of grease. In particular, when the total amount exceeds 10% by weight, not only an effect commensurate with the increase in content can be expected, but also the content of other components becomes relatively small, and these additives aggregate in the grease, Undesirable phenomena such as an increase in torque may be caused.

  The present invention will be further described below with reference to test examples, but the present invention is not limited thereby. Table 1 shows data on the density (15 ° C.) and kinematic viscosity (40 ° C.) of the base oil used in each example and each comparative example. Further, the consistency shown in Table 1 represents the 60-degree penetration penetration measured according to JISK2220 5.3, and the surface tension of the base oil at 25 ° C. is a value measured with a Dunui simple surface tension meter.

<Preparation of grease samples used in Examples 1 to 4 and Comparative Examples 3 to 4>
4,4'-diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MT, hereinafter referred to as MDI) is dissolved in half of the base oil shown in Table 1 at the ratio shown in Table 1, and the remaining half of the base oil is dissolved. A monoamine having a double equivalent of MDI was dissolved in the solution. The respective blending ratios and types are shown in Table 1.
While stirring the solution in which the MDI is dissolved, the solution in which the monoamine is dissolved is added thereto, and then the reaction is continued by stirring at 100 ° C. to 120 ° C. for 30 minutes to form a diurea compound in the base oil, and a grease sample is obtained. Obtained. The density, kinematic viscosity, and surface tension measurement results of the base oil used are shown in Table 1. Further, the consistency of the obtained grease sample was measured. Moreover, it used for the centrifugal oil separation test shown below, and measured the centrifugal oil separation degree. The measurement results are also shown in Table 1.

<Preparation of grease samples used in Comparative Example 1 and Comparative Example 2>
A base oil and lithium stearate were blended in the proportions shown in Table 1 to obtain a grease sample. The same items as in Example 1 were measured for the base oil and grease samples used. The results are also shown in Table 1.

<Centrifuge oil separation test>
Using a centrifuge, a 50 g grease sample was placed in a centrifuge tube, and the oil separation by centrifugation was calculated using the following formula when acceleration of 23000 G was applied for 7 hours at 40 ° C.
(Centrifugal oil separation,%) = (1−thickener concentration before test / thickener concentration after test) × 100

Examples 1 to 4, Comparative Example 1 and Comparative Example 3
Using the grease samples shown in Table 1, the room temperature high speed grease test-deep groove ball bearing (6204) shown below was conducted. The grease life is also shown in Table 1. At this time, the deep groove ball bearing (6204) has a crown shape as shown in FIG. 4 and is provided with a recessed oil reservoir in the pocket portion and chamfered at all contact portions with the ball including the edge of the recessed portion. A resin retainer (PA66 + GF 25 wt% blended) was used.

Example 2, Comparative Example 1 and Comparative Example 3
Using the grease samples shown in Table 1, the normal temperature high speed grease test-angular ball bearing shown below was conducted. The grease life is also shown in Table 1. At this time, the angular ball bearing is of a rice bran type as shown in FIG. 2 and is provided with a concave portion at the four corners of the pocket portion, and further provided with oil reservoirs at the concave portions at both axial ends of the pocket portion. A phenolic resin cage that was chamfered was used.

Comparative Example 2 and Comparative Example 4
Using the grease samples shown in Table 1, the normal temperature high speed grease test-deep groove ball bearing (6204) and the normal temperature high speed grease test-angular ball bearing shown below were performed. The grease life is also shown in Table 1.

<Normal Temperature High Speed Grease Test-Deep Groove Ball Bearing (6204)>
In a deep groove ball bearing (6204), 0.0235 g (about 0.5% by volume of the total space volume of the bearing) of a grease sample was sealed with the aim of the rolling surface, and a non-contact seal was made to prepare a test bearing. An axial load of 670 N and a radial load of 67 N were applied to the test bearing, and the test bearing was rotated at a rotational speed of 10000 rpm in a normal temperature environment. The time until seizure was measured as the grease life time. In this durability test, the dmN value, which is the product of the pitch circle diameter (mm) of the bearing and the rotational speed (rpm), is 350,000.

<Normal Temperature High Speed Grease Test-Angular Contact Ball Bearing>
Angular contact ball bearings (outer diameter 150 mm x inner diameter 100 mm, inner and outer rings SUJ2, rolling elements 13/32 inch silicon nitride ball) with grease sample aiming at rolling surface 3.0 g (about 10% by volume of total bearing space) A test bearing was made by sealing and non-contact sealing. The test bearing is cooled by outer cylinder cooling under a constant pressure of 1.8 GPa, and the bearing outer ring is rotated at a rotational speed of 14500 rpm while keeping the bearing outer ring at 50 ° C or less. The time until seizure is measured as the grease life time. did. The dmN value, which is the product of the pitch diameter (mm) of the bearing and the rotational speed (rpm), in this durability test is 1.85 million.

As shown in Table 1, the grease to be enclosed in high-speed rolling bearings is as follows: (1) A base thickener with a kinematic viscosity at 40 ° C of 15-30 mm ² / sec and a urea-based thickener of 3 wt% or more 9 (2) As a urea-based thickener, the monoamine component contains at least one selected from aliphatic monoamines and alicyclic monoamines in an amount of 50 mol% or more based on the total monoamines. (3) The base oil has a surface tension of 25 mN / m or more and a density of 0.95 g / cm ³ or less, and is a synthetic hydrocarbon oil, ester oil or alkyldiphenyl ether oil, or a mixed oil thereof. It turns out that it is preferable. (4) Further, it can be seen that it is preferable that chamfering is performed by providing an oil reservoir portion, a dampening portion, or the like in the recessed portion in the pocket portion of the resin cage.

  The high-speed rolling bearing of the present invention encloses a base oil having a predetermined kinematic viscosity with a predetermined amount of grease compounded with a predetermined urea compound as a thickening agent, and has an oil reservoir of a recess in a pocket portion of the cage. Since the rolling bearing is provided with a chamfering process by providing a portion and a thinning portion, the durability of the bearing under high-speed rotation is improved. For this reason, it can be suitably used as a rolling bearing incorporated in a spindle support part of a machine tool that slides and rotates at high speed such as a lathe, drilling machine, boring machine, milling machine, grinding machine, super finishing machine, and lapping machine. . In addition, unlike a method of continuously supplying lubricating oil such as the oil-air lubrication method, grease can be enclosed and used, so that the operating cost can be reduced and the space can be saved.

It is sectional drawing which shows the angular ball bearing which is one Embodiment of the high-speed rolling bearing of this invention. It is a perspective view of a rice bran type cage used for an angular ball bearing. It is a longitudinal cross-sectional view which shows the deep groove ball bearing which is other embodiment of the high-speed rolling bearing of this invention. It is a perspective view of a crown type cage used for a deep groove ball bearing. It is sectional drawing which shows an angular contact ball bearing.

Explanation of symbols

1,21 Angular contact ball bearing 2,12,22 Inner ring 3,13,23 Outer ring 4,14,24 Rolling element (steel ball)
5, 15, 25 Cage 5a, 15a Pocket portion inner surface 5b Slack portion 5c Oil reservoir portion 5d, 15d Edge of recess portion 6, 16 Seal member 7, 17 Grease 11 Deep groove ball bearing 15b Cross surface side oil reservoir portion 15c Bottom side Oil reservoir

Claims (8)

A high-speed rolling bearing that supports a high-speed rotating shaft,
The rolling bearing includes an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, a cage that holds the rolling elements in a pocket portion, and a seal member that covers an opening of a gap between the inner and outer rings. Comprising grease around the rolling element,
The retainer has a recess on the inner surface of the pocket portion, and at least the edge of the recess is chamfered,
The grease comprises a base oil and a urea thickener, the base oil has a kinematic viscosity at 40 ° C. of 15 to 30 mm ² / sec, and the urea thickener comprises a polyisocyanate component and A monoamine component obtained by reacting with a monoamine component, wherein the monoamine component contains at least one monoamine selected from aliphatic monoamines and alicyclic monoamines in an amount of 50 mol% or more based on the total monoamines. On the other hand, a high-speed rolling bearing characterized in that the urea-based thickener is blended in an amount of 3 wt% to less than 9 wt%.   The high speed rolling bearing according to claim 1, wherein the concave portion is an oil reservoir portion or a dull portion. The high-speed rolling bearing according to claim 1 or 2, wherein the base oil has a surface tension of 25 mN / m or more and a density of 0.95 g / cm ³ or less.   4. The high-speed rolling bearing according to claim 1, wherein the base oil is at least one oil selected from a synthetic hydrocarbon oil, an ester oil and an alkyl diphenyl ether oil.   The high-speed rolling bearing according to any one of claims 1 to 4, wherein the cage is a resin cage.   6. The high-speed rolling bearing according to claim 5, wherein the resin used in the cage is a polyamide resin, a phenol resin, or a polyether ether ketone resin.   The high-speed rolling bearing according to any one of claims 1 to 6, wherein the high-speed rolling bearing is a bearing that supports a main shaft of a machine tool.   The high-speed rolling bearing according to claim 7, wherein the high-speed rolling bearing is an angular ball bearing or a cylindrical roller bearing.

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