JP2008163995A - Grease filled double row angular bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grease filled double row angular bearing to surely prevent a heating problem, a brittle peeling problem, and an absorption phenomenon of a seal lip, when using a single row multi-point contact bearing. <P>SOLUTION: The grease filed double row angular bearing comprises: an inner ring 1 and an outer ring 2 having a ring race of two rows; a plurality of rolling elements 3 disposed in two rows between the inner and outer rings, a seal member 5 to block both ends openings of the inner and outer rings; and grease 6 filled around at least rolling bodies 3. The seal member 5 has a seal structure in which a projection is provided in an inner surface of the seal lip, and the seal lip is pushed into the inside to contact the inner surface of a seal groove, so that an air passage is formed to communicate with the bearing inside and the bearing outside. The grease 6 contains at least one 0.05 to 10 weight parts of an aluminum-based additive selected from aluminum dust and an aluminum compound with respect to 100 weight parts of base grease consisting of a base oil and a puffing agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a grease-enclosed double-row angular bearing using a seal member having a contact-type seal structure, and particularly as a rolling bearing for automotive electrical components such as an alternator, an electromagnetic clutch for a car air conditioner, an intermediate pulley, and an electric fan motor, and an auxiliary machine. The present invention relates to a grease-enclosed double row angular bearing used.

  Bearings used for automobile electrical accessories have a brittle peeling problem due to sliding between a bearing rolling surface and a bearing ring because they are used at high temperature and high speed rotation. In response to recent demands for compactness, the bearing size tends to be reduced. One type of bearing compaction, which normally uses double row bearings, may be supported by single row bearings. To compensate for the reduced life when single row bearings are used, single row multipoint contact bearings ( 4 point contact and 3 point contact) (see, for example, Patent Document 1).

  For example, as shown in FIG. 7, the inner ring 32 and the outer ring 33 are integrated, and the cross-sectional shapes of the respective rolling surfaces 34 and 35 have the same radius of curvature with the centers 36a and 37a of the rolling surface bottom portions 36 and 37 as boundaries. Each has two centers of curvature. The positions of the two curvature centers of the inner race 32 and the outer race 33, respectively, of the rolling surfaces 34 and 35 are the same in the radial direction, and in the axial direction, the Gothic arch shape is arranged symmetrically with respect to the center of the bottom of each rolling surface. ing. The rolling element 38 has a contact angle α between the inner ring 32 and the outer ring 33, and grease 39 is sealed at least around the rolling element 38. The single row multipoint contact bearing has an axial width of about 12 to 14 mm, which is narrower than the conventional double row angular bearing (about 20 to 22 mm) and can be made compact.

  However, in the case of a single-row multipoint contact bearing, since the rolling element has two rotation shafts, the rolling element becomes a sliding motion instead of a rolling motion, and this sliding motion eliminates the formation of an oil film of lubricating oil and excessive heat generation. There is a problem that a brittle exfoliation problem occurs in combination with a problem of performing and a reason described later.

In rolling bearings, a seal structure using a seal member is employed in order to prevent grease inside the bearing from leaking to the outside and to prevent foreign matter from entering from the outside.
In this seal structure, a seal member formed of an elastic body such as synthetic rubber is mounted between a seal groove provided on the inner ring outer diameter surface of the bearing and a seal member fixing groove on the outer ring inner diameter surface facing the seal groove. A contact-type seal structure is adopted in which a seal lip is provided on the inner peripheral portion of the seal member, and the seal lip is brought into contact with the seal groove.
In the contact-type seal structure, in general, in order to improve the sealing performance, the contact area between the seal lip and the seal groove is increased, or the contact pressure of the seal lip is increased. However, when the contact area between the seal lip and the seal groove is increased, frictional heat between the seal lip and the seal groove is generated as the rolling bearing rotates.

  When the temperature of the rolling bearing rises due to this frictional heat or heat conduction from the outside, and then the rolling bearing is cooled, the pressure inside the rolling bearing becomes negative with respect to the outside. As a result, the seal lip of the seal member is firmly adhered to the seal groove, and there is a possibility that a so-called adsorption phenomenon occurs in which the bearing torque is remarkably increased.

In order to prevent this adsorption phenomenon, various contrivances have been conventionally made in contact-type seal structures. For example, by providing one or a plurality of protrusions at the tip of the seal lip, an air passage is formed around the protrusion in the sliding contact portion with the seal groove to keep the pressure balance inside and outside the bearing uniform ( Patent Document 2 Paragraph 0018, FIG. 3).
In addition, there is an apparatus in which a pressure balance inside and outside of the bearing is kept uniform by providing an air passage that communicates between the inside of the bearing and the outside of the bearing on the outer peripheral edge of the seal member (see Patent Document 3 and Patent Document 4).

As in the above-mentioned Patent Document 2, when one or more protrusions are provided at the tip of the seal lip, when the rolling bearing is operated, the protrusion is worn and functions as a normal seal lip. The adsorption phenomenon can be prevented before the rolling bearing is operated. However, after the protrusions wear out after operation, the adsorption phenomenon cannot be prevented. Further, before the protrusions are worn out, the inside and outside of the bearing are not shut off, and there is a problem that foreign matter enters from the outside.
Further, as in Patent Document 3 and Patent Document 4 described above, an air passage that communicates between the inside of the bearing and the outside of the bearing is provided on the outer peripheral edge of the seal member, so that the adsorption phenomenon is always prevented regardless of the operation of the bearing. However, as in the case of the above-mentioned Patent Document 2, there is a problem that foreign matter enters from the outside because the inside and outside of the bearing are not shut off.

Further, grease is mainly used for lubrication of these bearings. Due to severe conditions of use such as high-speed rotation at high temperatures, specific brittle debonding accompanied by a change in white structure occurs early on the rolling surface of the bearing, which is a problem.
This specific exfoliation is different from the exfoliation from the inside of the rolling contact surface caused by normal metal fatigue, and is considered to be due to hydrogen embrittlement caused by hydrogen due to a fracture phenomenon that occurs from a relatively shallow surface of the rolling surface. Yes. As a method for preventing such a specific peeling phenomenon accompanied by a white tissue change that occurs at an early stage, for example, a method of adding a passivating agent to grease is known (see Patent Document 5). A method of adding bismuth dithiocarbamate to a grease composition is known (see Patent Document 6).
However, in recent years, electrical components and accessories in automobiles, motors in industrial machines, etc. are increasingly used under high temperature conditions, such as high-speed operation-sudden deceleration operation-rapid acceleration operation-sudden stop. The method of adding a passivating agent and bismuth dithiocarbamate has become inadequate as a measure for preventing the peeling phenomenon.
JP-A-11-336795 JP 2000-257640 A JP 2000-65074 A JP 2002-364655 A JP-A-3-210394 JP-A-2005-42102

  The present invention has been made in order to cope with such a problem. In response to a request for downsizing, it is possible to reliably prevent a heat generation problem and a brittle peeling problem caused by a sliding motion when using a single-row multipoint contact bearing. An object of the present invention is to provide a grease-enclosed double-row angular bearing capable of preventing the adsorption phenomenon while ensuring sealing performance at all times.

  The grease-enclosed double-row angular bearing of the present invention includes an inner ring having two rows of raceways, an outer race having a raceway corresponding to each race of the inner race, and a plurality of rows arranged between the inner and outer races in two rows. A rolling structure and a seal structure in which one of the peripheral edge portions of the inner ring and the outer ring of the inner ring is in sliding contact with a seal groove formed at the end of one track, and the other peripheral portion is fixed to the end of the other track. A grease-enclosed double-row angular bearing comprising a seal member having at least a grease encapsulated around the rolling element, wherein the seal structure has a peripheral edge of the seal member in sliding contact with the seal groove as a seal lip A protrusion is provided on the inner surface of the seal lip, and the protrusion is normally not in contact with the inner surface of the seal groove, and there is a pressure difference between the inside of the bearing partitioned by the seal member and the outside of the bearing. Up When the seal lip is pushed inward, the seal lip comes into contact with the inner surface of the seal groove, and the contact of this protrusion partially elastically deforms the seal lip in the vicinity of the contact so that the inside of the bearing and the outside of the bearing The grease is formed by adding an additive to a base grease composed of a base oil and a thickener, and the additive is selected from aluminum powder and an aluminum compound. It contains at least one aluminum-based additive, and the compounding ratio of the aluminum-based additive is 0.05 to 10 parts by weight with respect to 100 parts by weight of the base grease.

The projections are formed on the inner surface of the seal lip at a predetermined interval along the sliding contact portion.
Further, the protrusion is formed on the inner surface of the seal lip by a protrusion that protrudes over the entire circumference along the tip sliding contact portion, and a notch groove is provided in a direction crossing the protrusion. .

The aluminum compound is at least one compound selected from aluminum carbonate and aluminum nitrate.
The thickener is a urea-based thickener.
Further, the base oil is at least one oil selected from alkyl diphenyl ether oil and poly-α-olefin oil.

The grease-enclosed double-row angular bearing of the present invention is switched from a single-row multi-point contact bearing whose rolling element is mainly in sliding motion to a double-row angular bearing mainly in rolling motion in applications such as electromagnetic clutches. The oil film formation inhibition can be made difficult to occur.
In addition, by adopting a seal member structure in which an air passage that communicates between the inside and outside of the bearing is formed, the seal lip is prevented from adhering to the seal groove wall, thereby preventing wear and ensuring sealing performance. Can do.
Furthermore, by encapsulating grease containing an aluminum additive, the aluminum additive added to the grease reacts on the frictional wear surface or the new metal surface exposed by wear, and an aluminum film is formed on the bearing rolling surface along with iron oxide. In addition, it is possible to suppress the occurrence of delamination due to hydrogen embrittlement and the like seen in bearings used in automobiles and industrial machines.
As a result of these effects acting synergistically, it is possible to dramatically improve the life of the narrow double-row angular bearing having the axial width of the single-row multipoint contact bearing.
For this reason, it can be suitably used as a rolling bearing for automotive electrical components such as alternators, car air conditioner electromagnetic clutches, intermediate pulleys, and electric fan motors, and auxiliary machines.

  First, in the grease-enclosed double-row angular bearing of the present invention, a seal structure in which an air passage that connects the inside of the bearing and the outside of the bearing is formed for the purpose of preventing the adsorption phenomenon while always ensuring sealing performance. To do. The periphery of the seal member that is in sliding contact with the seal groove is used as a seal lip, and a protrusion is provided on the inner side of the seal lip, and the protrusion is normally not in contact with the inner surface of the seal groove. When the seal lip is pushed inward due to a pressure difference between the inside of the bearing and the outside of the bearing, the seal lip contacts the inner surface of the seal groove. Is partially elastically deformed to form an air passage communicating the inside of the bearing with the outside of the bearing.

  When an adsorption phenomenon occurs in this configuration, the seal lip is pushed inward, and at the same time, the protrusion is pushed against the inner surface of the seal groove. At this time, the seal lip in the vicinity of the contact position of the projection (near the pressed position) is partially elastically deformed with respect to other portions due to the presence of the projection. That is, the seal lip in the vicinity of the contact of the protrusion cannot contact the inner surface of the seal groove, and an air passage that connects the inside of the bearing and the outside of the bearing is formed by the non-contact.

  Further, when both the protrusion and the seal lip tip are in contact with the inner surface of the seal groove, due to the difference in contact pressure between the protrusion and the seal lip tip, the protrusion tip has a sliding resistance of the seal lip. It becomes larger than the sliding resistance of the tip. When the bearing is rotated in this state, twisting occurs so that the tip of the seal lip undulates and an air passage is formed.

  For this reason, the pressure balance inside and outside the bearing can be kept instantaneously uniform to prevent the adsorption phenomenon. Further, the air passage for maintaining the pressure balance is immediately closed when the pressure balance inside and outside the bearing becomes uniform, and the seal lip is in a normal state. Therefore, the entry of foreign matter from the outside can be minimized. Further, since the air passage is narrow, grease does not leak.

  Specifically, a ball is interposed between both races of the inner ring and the outer ring and grease is filled, and both end surfaces of both raceways are closed with a seal member, and the seal member has one peripheral portion of one raceway. In a seal structure of a grease-enclosed double row angular bearing in which the other peripheral portion is slidably contacted with the seal groove formed at the end and fixed to the end of the other raceway, the periphery of the seal member slidably contacting the seal groove is used as a seal lip. A protrusion is provided on the inner surface of the seal lip, and the protrusion is normally not in contact with the inner surface of the seal groove, and a pressure difference is generated between the inside of the bearing and the outside of the bearing that is partitioned by the seal member. When the lip is pushed inward, it comes into contact with the inner surface of the seal groove, and the contact of this projection partially elastically deforms the seal lip in the vicinity of the contact so that the inside of the bearing and the outside of the bearing are connected. It had adopted a configuration in which as the air passage for passing is formed.

  In the above configuration, if a configuration is adopted in which the protrusions are formed on the inner surface of the seal lip at predetermined intervals along the tip sliding contact portion, the protrusion is pressed against the inner surface of the seal groove when an adsorption phenomenon occurs. At the same time, the seal lip near the protrusion is elastically deformed. For this reason, the tip sliding contact portion of the seal lip is separated from the inner surface of the seal groove, and an air passage is formed around the protrusion to communicate the bearing interior and the bearing exterior.

  Adopting a configuration in which the protrusion is formed on the inner surface of the seal lip by a ridge protruding over the entire circumference along the tip sliding contact portion, and a notch groove is provided in a direction crossing the ridge. When the phenomenon occurs, the protrusion is pressed against the inner surface of the seal groove, and the seal lip near the protrusion is elastically deformed. For this reason, the tip slidable contact portion of the seal lip is separated from the inner surface of the seal groove, and an air passage that communicates the inside of the bearing and the outside of the bearing is formed in the protruding groove.

Hereinafter, an embodiment of a grease-enclosed rolling bearing of the present invention will be described based on the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a grease-enclosed double-row angular bearing.
As shown in FIG. 1, this double-row angular bearing has a bearing space in which two rows of rolling elements 3 are held by a cage 4 between an inner ring 1 and an outer ring 2 on the inner peripheral surface of the outer ring 2. This is a double-row angular contact ball bearing sealed with a seal member 5 fixed in the locking groove. Grease 6 is sealed at least around the rolling element 3. The rolling element 3 has a contact angle β between the inner ring 1 and the outer ring 2.
The conventional double-row angular bearing has an axial width of about 20 to 22 mm, and the grease-filled double-row angular bearing of the present invention is used as a rolling bearing for automobile electrical parts, auxiliary machines, etc., for example, as shown in FIG. The width of the multipoint contact bearing is preferably as narrow as the axial width of 12 to 14 mm. At that time, the space volume inside the bearing is reduced by reducing the width dimension, and as a measure to reduce the amount of grease filled, the excess volume of the inner and outer rings of the bearing is reduced, the space volume is secured, the amount of grease filled It is preferable to employ a method for increasing the number of bearings as much as possible, a method for optimizing bearing internal specifications such as contact angle, groove curvature, ball diameter, number of balls, etc., suppressing bearing self-heating and preventing deterioration of grease.

FIG. 2 is a partial cross-sectional view showing the seal structure of the grease-enclosed double row angular bearing of the embodiment. As shown in FIG. 2, the rolling bearing of this embodiment includes an inner ring 1, an outer ring 2, a rolling element 3 provided so as to freely roll between the inner ring 1 and the outer ring 2, the inner ring 1 and the outer ring. 2 and an annular seal member 5 fitted to both axial end faces.
An inner ring raceway 1 a on which the rolling element 3 rolls is provided on the outer diameter surface of the inner ring 1, and an outer ring raceway 2 a facing the inner ring raceway 1 a is provided on the inner diameter surface of the outer ring 2. Circumferential seal grooves 7 and 7 are formed on both sides of the inner ring raceway 1a, and seal member locking grooves 8 and 8 are formed on the inner diameter surface of the outer ring 2 facing the seal grooves 7, respectively. The outer peripheral edge 9 of the seal member 5 is locked in the seal member locking groove 8.

  The seal member 5 is obtained by reinforcing an elastic body 11 made of synthetic rubber or the like with a metal core 10, and a seal lip 12 extending inward in the radial direction is formed on the elastic body 11. The seal lip 12 includes a waist portion 13 in which the thickness of the elastic body 11 is reduced, a dust lip 14 extending outward in the axial direction from an end portion of the waist portion 13, and an inward direction from the end portion of the waist portion 13. And a main lip 15 whose tip is in sliding contact with the inner surface 16 of the seal groove 7 is formed.

  As shown in FIG. 3A, the main lip 15 has a protrusion 17 that protrudes toward the inner surface 16 on the surface facing the inner surface 16 of the seal groove 7. One or a plurality of projections 17 are provided on the inner side of the main lip 15 along the tip (the inner peripheral edge of the seal member 5).

  When the sealing member 5 configured as described above is locked in the sealing member locking groove 8 of the outer ring 2, the tip portion of the main lip 15 is in contact with the inner side surface 16 of the sealing groove 7 (FIG. 3). (See (b)). In this state, the protrusion 17 does not contact the inner surface 16 of the seal groove 7 in a state where there is no pressure difference between the inside and the outside of the bearing, so that the sealing performance is not impaired.

  Next, a pressure difference between the inside and outside of the bearing occurs, such as when the bearing is cooled after the temperature change during the transportation of the rolling bearing or the generation of frictional heat accompanying the rotation of the rolling bearing, and the seal lip 12 When pushed inward, the projection 17 provided on the main lip 15 contacts the inner side surface 16 of the seal groove 7 as shown in FIG. As a result, the tip of the main lip 15 in the vicinity of the protrusion 17 is elastically deformed outward and is separated from the inner surface 16 of the seal groove 7.

  In this state, an air passage 18 that communicates between the inside and outside of the bearing is formed around the protrusion 17, and the pressure difference between the inside and outside of the bearing is eliminated, thereby preventing the adsorption phenomenon of the bearing. Since the air passage 18 is formed only around the protrusion 17, the tip end portion of the main lip 15 where the protrusion 17 does not exist is kept in contact with the inner surface 16 of the seal groove 7, and the sealing performance is Secured. Further, as soon as the pressure difference between the inside and outside of the bearing is eliminated, the seal lip 12 returns to the normal state, and the deterioration of the sealing performance is minimized.

  Further, if the pressure difference between the inside and outside of the bearing is large and the protrusion 17 is crushed due to contact with the inner surface 16 of the seal groove 7 or the pressure difference inside and outside the bearing is very small, as shown in FIG. Both the protrusion 17 and the tip end portion of the main lip 15 are in an adsorbing state in contact with the inner surface 16 of the seal groove 7. In the suction state in this case, the contact pressure of the tip of the protrusion 17 that contacts the inner surface 16 of the seal groove 7 is larger than the tip of the main lip 15 that contacts the inner surface 16 of the seal groove 7.

  Due to this difference in contact pressure, the sliding resistance of the tip of the projection 17 becomes larger than the sliding resistance of the tip of the main lip 15, and when the bearing is rotated in this attracted state, FIG. As shown, the protrusion 17 maintains contact with the inner surface 16 of the seal groove 7 and tries to rotate with the inner surface 16. At this time, since the front end portion of the main lip 15 slides, as shown in FIG. 4C, the front end portion of the main lip 15 (inner peripheral edge of the seal member 5) is elastically deformed so as to undulate. . An air passage 19 is formed when the tip of the main lip 15 is elastically deformed, and suction is released.

Another example of this embodiment is shown in FIGS. In the embodiment in this case, as shown in FIG. 5 (a), a ridge 20 projecting over the entire circumference along the tip sliding contact portion is formed on the inner surface of the main lip 15, and the ridge 20 is crossed. This is different from the above-described embodiment in that a notch groove 21 is provided in the direction to be cut. Other configurations are the same as those in the above-described embodiment.
As shown in FIG. 5B, the protrusion 20 does not contact the inner surface 16 of the seal groove 7 in a state where there is no pressure difference between the inside and the outside of the bearing, so that the sealing performance is not impaired. The notch groove 21 is not limited to a part formed by cutting out a part of the ridge 20, but includes a part formed by reaching the inner surface of the main lip 15 and dividing the ridge 20. .

  Next, a pressure difference between the inside and outside of the bearing occurs, such as when the bearing is cooled after the temperature change during the transportation of the rolling bearing or the generation of frictional heat accompanying the rotation of the rolling bearing, and the seal lip 12 is moved to the inside. As shown in FIG. 5 (c), the protrusion 20 provided on the main lip 15 contacts the inner surface 16 of the seal groove 7. As a result, the tip of the main lip 15 in the vicinity of the ridge 20 is elastically deformed outward and away from the inner surface 16 of the seal groove 7.

  In this state, an air passage 22 that communicates the inside and outside of the bearing is formed by the notch groove 21 of the protrusion 20, and the pressure difference between the inside and outside of the bearing is eliminated, thereby preventing the bearing adsorption phenomenon. At the same time, since the protrusions 20 projecting all around the tip of the main lip 15 are in contact with the inner surface 16 of the seal groove 7, the sealing performance can be ensured.

  Further, if the pressure difference between the inside and outside of the bearing is large and the ridge 20 is crushed by contact with the inner surface 16 of the seal groove 7 or the pressure difference between the inside and outside of the bearing is very small, as shown in FIG. In addition, both the protrusion 20 and the tip of the main lip 15 are brought into the suction state in contact with the inner surface 16 of the seal groove 7. In the suction state in this case, the contact pressure of the tip of the protrusion 20 that contacts the inner surface 16 of the seal groove 7 is larger than the tip of the main lip 15 that contacts the inner surface 16 of the seal groove 7.

  Due to this difference in contact pressure, the sliding resistance of the tip of the protrusion 20 becomes larger than the sliding resistance of the tip of the main lip 15, and when the bearing is rotated in this attracted state, FIG. As shown in FIG. 5, the protrusion 20 maintains a state in contact with the inner surface 16 of the seal groove 7 and tries to rotate together with the inner surface 16. At this time, since the tip of the main lip 15 slides, as shown in FIG. 6C, the tip of the main lip 15 (inner peripheral edge of the seal member 5) is elastically deformed so as to wave in an uneven shape. . The air passage 23 is formed at the time of elastic deformation of the front end portion of the main lip 15, and the suction is released.

The aluminum-based additive added to the grease used for the grease-enclosed double-row angular bearing of the present invention is at least one selected from aluminum powder and aluminum compound. Aluminum compounds include aluminum carbonate, aluminum sulfide, aluminum chloride, aluminum nitrate and its hydrate, aluminum sulfate, aluminum fluoride, aluminum bromide, aluminum iodide, aluminum oxide and its hydrate, aluminum hydroxide, selenium Aluminum fluoride, aluminum telluride, aluminum phosphate, aluminum phosphide, lithium aluminate, magnesium aluminate, aluminum selenate, aluminum titanate, aluminum zirconate and other inorganic aluminum, aluminum benzoate, aluminum citrate and other organic aluminum Is mentioned. These aluminum additives may be added to the grease alone or in combination of two or more.
Particularly preferable in the present invention is an aluminum powder having a high extreme pressure effect because it is excellent in heat resistance and hardly decomposes thermally.

The mixing ratio of the aluminum-based additive is 0.05 to 10 parts by weight with respect to 100 parts by weight of the base grease. That is, (1) when the aluminum additive is only aluminum powder, 0.05 to 10 parts by weight of aluminum powder with respect to 100 parts by weight of the base grease, and (2) when the aluminum additive is only aluminum compound, 0.05 to 10 parts by weight of aluminum compound per 100 parts by weight of grease, and (3) when aluminum additive is aluminum powder and aluminum compound, aluminum powder and aluminum compound are added to 100 parts by weight of base grease. Combine 0.05 to 10 parts by weight.
If the blending ratio of the aluminum-based additive is less than 0.05 parts by weight, peeling on the rolling surface due to hydrogen embrittlement cannot be effectively prevented. Moreover, even if it exceeds 10 parts by weight, the anti-peeling effect will not be improved further.

Base oils that can be used in the present invention include mineral oils such as spindle oil, refrigerator oil, turbine oil, machine oil, dynamo oil, highly refined mineral oil, liquid paraffin, polybutene, GTL oil synthesized by the Fischer-Tropsch method, poly- Hydrocarbon synthetic oil such as α-olefin oil, alkylnaphthalene, alicyclic compound, or natural oil, polyol ester oil, phosphate ester oil, polymer ester oil, aromatic ester oil, carbonate ester oil, diester oil, Non-hydrocarbon synthetic oils such as polyglycol oil, silicone oil, polyphenyl ether oil, alkyldiphenyl ether oil, alkylbenzene oil, and fluorinated oil can be used.
Among these, it is preferable to use alkyl diphenyl ether oil or poly-α-olefin oil excellent in heat resistance and lubricity.

Thickeners that can be used in the present invention include benton, silica gel, fluorine compounds, lithium soap, lithium complex soap, strong lucium soap, calcium complex soap, aluminum soap, aluminum complex soap, and other soaps, diurea compounds, polyurea compounds, etc. These urea compounds are mentioned.
Of these, urea compounds are desirable in view of heat resistance, cost, and the like.

  A urea compound is obtained by reacting an isocyanate compound and an amine compound. In order not to leave a reactive free radical, the isocyanate group of the isocyanate compound and the amino group of the amine compound are preferably blended so as to be approximately equivalent.

  A diurea compound is obtained by reaction of a diisocyanate and a monoamine, for example. Examples of the diisocyanate include phenylene diisocyanate, tolylene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, hexane diisocyanate, etc., and monoamines include octylamine, dodecylamine, hexadecylamine, stearylamine, Examples include oleylamine, aniline, p-toluidine, cyclohexylamine and the like. The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine include those similar to those used for the production of the diurea compound. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, xylenediamine, And diaminodiphenylmethane.

By adding a thickener such as a urea compound to the base oil, a base grease for blending the aluminum additive and the like can be obtained. A base grease using a urea compound as a thickener is prepared by reacting an isocyanate compound and an amine compound in a base oil.
The blending ratio of the thickener in 100 parts by weight of the base grease is 1 to 40 parts by weight, preferably 3 to 25 parts by weight. If the content of the thickener is less than 1 part by weight, the thickening effect will be reduced, making it difficult to make grease, and if it exceeds 40 parts by weight, the resulting base grease will be too hard and the desired effect will not be obtained. Become.

  In addition to the aluminum-based additive, a known grease additive may be included 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 include solid lubricants, metal sulfonates, rust inhibitors such as polyhydric alcohol esters, friction reducers such as organic molybdenum, oil 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.

Examples 1 to 8
In half of the base oil shown in Table 1, 4,4-diphenylmethane diisocyanate (Millionate MT manufactured by Nippon Polyurethane Industry Co., Ltd., hereinafter referred to as MDI) is dissolved in 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.
A solution in which monoamine was dissolved was added while stirring the solution in which MDI was dissolved, and then the reaction was continued for 30 minutes at 100 ° C. to 120 ° C. to produce a diurea compound in the base oil.
To this, an aluminum-based additive and an antioxidant were added in the proportions shown in Table 1, and the mixture was further stirred at 100 to 120 ° C. for 10 minutes. Thereafter, the mixture was cooled and homogenized with three rolls to obtain a grease.

In Table 1, the synthetic hydrocarbon oil used as the base oil is Shinflud 601 manufactured by Nippon Steel Chemical Co., Ltd. with a kinematic viscosity of 30 mm ² / sec at 40 ° C, and the alkyldiphenyl ether oil is Matsumura with a kinematic viscosity of 97 mm ² / sec at 40 ° C. Moresco High Lube LB100 manufactured by Petroleum Corporation was used. Moreover, the hindered phenol by Sumitomo Chemical Co., Ltd. was used for antioxidant.

  The obtained grease was subjected to a rapid acceleration / deceleration test. Test methods and test conditions are shown below. The results are shown in Table 1.

<Rapid acceleration / deceleration test>
An inner ring rotating rolling bearing that simulates an alternator that is an example of an electrical accessory and supports the rotating shaft (double row angular bearing: made by SUJ2, outer diameter 52 mm, inner diameter 35 mm, axial width 12 mm, Fig. 2 to Fig. 2 The above grease was sealed in the possession of the seal structure shown in Fig. 4 and a rapid acceleration / deceleration test was conducted. The rapid acceleration / deceleration test conditions are as follows: the load load on the pulley attached to the tip of the rotating shaft is set to 1960 N, the operating speed is set to 0 rpm to 18000 rpm, and a current of 0.1 A flows through the test bearing. The test was conducted. Then, abnormal peeling occurred in the bearing, and the time when the vibration of the vibration detector exceeded the set value and the generator stopped (peeling life time, h) was measured. The test was terminated after 300 hours.

Comparative Examples 1 to 3
In accordance with the method according to Example 1, the base grease was prepared by selecting the thickener and the base oil at the blending ratio shown in Table 1, and the additive was further blended to obtain a grease. The obtained grease was evaluated by conducting the same test as in Example 1. The results are shown in Table 1.

  As shown in Table 1, in each example, all the rapid acceleration / deceleration tests showed excellent results of 200 hours or longer (peeling life time). This is considered to be because the specific exfoliation accompanied by the white texture change that occurs on the rolling surface can be effectively prevented by adding the aluminum-based additive at a predetermined ratio.

  The grease-enclosed double-row angular bearing of the present invention can reliably prevent heat generation problems and brittle peeling problems on the rolling surface, has excellent bearing life, and can prevent adsorption phenomenon while always ensuring sealing performance. It can be suitably used as a bearing for automobile electrical parts such as alternators, electromagnetic clutches for car air conditioners, intermediate pulleys, and electric fan motors, and auxiliary machines.

It is a fragmentary sectional view of a grease enclosure double row angular bearing. It is a fragmentary sectional view showing a seal structure of a grease enclosure double row angular bearing of an embodiment. (A) Cross-sectional perspective view showing protrusions provided on the lip, (b) Cross-sectional view showing a normal state of the above-mentioned seal lip, (c) Cross-sectional view showing an adsorbed state of the above-mentioned seal lip. (A) Cross-sectional view showing a state in which the lip and projections are in contact with the seal groove, (b) Cross-sectional view taken along line AA in (a), (c) State of the lip tip when the inner ring is rotated It is sectional drawing which showed. (A) A cross-sectional perspective view showing a protrusion provided on a seal lip of another example of the embodiment, (b) a cross-sectional view showing a normal state of the above-mentioned seal lip, and (c) an adsorbed state of the above-mentioned seal lip. It is sectional drawing shown. (A) A sectional view showing a state in which the lip and the ridge described above are in contact with the seal groove, (b) a sectional view taken along line BB in (a), and (c) a front end of the lip when the inner ring is rotated. It is sectional drawing which showed the state. It is a fragmentary sectional view of a single row 4 point contact bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 1a Inner ring raceway 2 Outer ring 2a Outer ring raceway 3 Rolling element 4 Cage 5 Seal member 6 Grease 7 Seal groove 8 Seal member engagement groove 9 Outer peripheral edge part 10 Core metal 11 Elastic body 12 Seal lip 13 Waist part 14 Dustrip 15 Main Lip 16 Inner surface 17 Protrusion 18 Air passage 19 Air passage 20 Projection 21 Notch groove 22 Air passage 23 Air passage 31 Single row four-point contact ball bearing 32 Inner ring 33 Outer ring 34 Inner ring rolling surface 35 Outer ring rolling surface 36 Inner ring rolling Running surface bottom 36a Center of inner ring rolling surface bottom 37 Outer ring rolling surface bottom 37a Center of outer ring rolling surface bottom 38 Rolling element 39 Grease

Claims (6)

An inner ring having two rows of raceways, an outer race provided with a raceway corresponding to each race of the inner race, a plurality of rolling elements arranged in two rows between the inner and outer races, and both ends of the inner and outer races A seal member having a seal structure in which one peripheral portion of the open portion is in sliding contact with a seal groove formed at the end of one track and the other peripheral portion is fixed to the end of the other track, and at least around the rolling element A grease-enclosed double row angular bearing with grease encapsulated in
In the seal structure, the periphery of the seal member that is in sliding contact with the seal groove is used as a seal lip, and a protrusion is provided on the inner surface of the seal lip, and the protrusion is normally not in contact with the inner surface of the seal groove. When the seal lip is pushed inward due to a pressure difference between the inside of the bearing and the outside of the bearing partitioned by the seal member, the inner surface of the seal groove is contacted, The seal lip in the vicinity of the contact is partially elastically deformed to form an air passage that communicates the inside of the bearing with the outside of the bearing.
The grease comprises a base grease composed of a base oil and a thickener, and the additive contains at least one aluminum-based additive selected from aluminum powder and an aluminum compound. A grease-enclosed double-row angular bearing characterized in that the mixing ratio of the system additive is 0.05 to 10 parts by weight with respect to 100 parts by weight of the base grease.   The grease-enclosed double-row angular bearing according to claim 1, wherein the protrusions are formed on the inner surface of the seal lip at a predetermined interval along a sliding contact portion thereof.   The protrusion is formed on the inner surface of the seal lip by a ridge protruding over the entire circumference along the tip sliding contact portion, and a notch groove is provided in a direction crossing the ridge. The grease-enclosed double-row angular bearing according to claim 1.   The grease-enclosed double-row angular bearing according to claim 1, 2 or 3, wherein the aluminum compound is at least one compound selected from aluminum carbonate and aluminum nitrate.   The grease-enclosed double-row angular bearing according to any one of claims 1 to 4, wherein the thickener is a urea-based thickener.   The grease-enclosed double-row angular bearing according to any one of claims 1 to 5, wherein the base oil is at least one oil selected from alkyl diphenyl ether oil and poly-α-olefin oil. .

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