JP2008215430A - Grease-sealed rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grease-sealed rolling bearing capable of effectively preventing fragile separation on a rolling travel surface, in the rolling bearing used under high temperature-high speed rotation. <P>SOLUTION: This grease-sealed rolling bearing is provided by blocking up both end surface of both tracks by a seal member 4, by filling grease 24 by interposing a ball 3 between both tracks of an inner ring 1 and an outer ring 2, and has a seal structure that the peripheral edge of the seal member 4 slidingly contacting with a seal groove 7 is formed as a seal lip 12, and a projection is arranged on an inner surface of the seal lip 12, and its projection does not contact with a seal groove inside surface 16 at ordinary time, and when the seal lip is pushed inside when a pressure difference is caused between the bearing inside and the bearing outside, an air passage is formed for communicating the bearing inside with the bearing outside by contacting with the inside surface 16 of the seal groove 7. The grease is formed by blending at least an aluminum-based additive with base grease composed of base oil and a thickening agent, and a blending rate of the aluminum-based additive is set to 0.05-10 pts.wt. to the base grease of 100 pts.wt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a grease-filled rolling bearing, and in particular, an automotive electrical apparatus and an auxiliary machine such as an alternator, an electromagnetic clutch for a car air conditioner, an intermediate pulley, and an electric fan motor that prevent a specific peeling phenomenon that occurs on the rolling surface of the inner and outer rings of the bearing. The present invention relates to a grease-filled rolling bearing used as a rolling bearing.

Electrical components and accessories in automobiles, motors in industrial machines, etc. are required to be downsized, high performance, and high output year by year, and usage conditions are becoming stricter. For these, rolling bearings are used, and grease is mainly used for lubrication. However, due to severe conditions of use such as high-speed rotation at high temperatures, specific brittle delamination accompanied by white structure change occurs at an early stage on the rolling surface of the rolling 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. Various methods have been proposed as a method for preventing such a peculiar exfoliation phenomenon accompanied with a white structure change that occurs at an early stage, and there are roughly classified ones using a lubricant and bearing materials / heat treatment.

The method using a lubricant includes one that stabilizes the function of the grease by a seal structure that prevents grease leakage.
With respect to the seal structure of the bearing, 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 increases.

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 sliding contact with the seal groove to keep the pressure balance inside and outside the bearing uniform. (See Patent Document 1)
In some cases, an air passage communicating between the inside of the bearing and the outside of the bearing is provided on the outer peripheral edge of the seal member, thereby maintaining a uniform pressure balance inside and outside the bearing. (See Patent Documents 2 and 3)

As in the above-mentioned Patent Document 1, in the case where one or a plurality of 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 Documents 2 and 3 above, the adsorption phenomenon can be always prevented on the outer peripheral edge of the seal member regardless of before and after the operation of the bearing. Since the outside is not blocked, there is a problem that foreign matter enters from the outside.

Further, as a method for preventing the peeling phenomenon with a lubricant, a method of adding a passivating agent to the grease composition (see Patent Document 4) and a method of adding bismuth dithiocarbamate to the grease composition are known (patents). Reference 5).
However, in recent years, electrical components and accessories in automobiles, motors in industrial machines, etc., are increasingly used in rolling bearings at high temperatures, such as frequent 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 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 to cope with such problems, and provides a grease-filled rolling bearing capable of effectively preventing brittle peeling on the rolling surface in a rolling bearing used at high temperature and high speed. With the goal.

  The grease-enclosed rolling bearing of the present invention has a ball interposed between both races of the inner ring and the outer ring and is filled with grease, and both end faces of both raceways are closed with a seal member. A grease-filled rolling bearing having a seal structure that is in sliding contact with the seal groove formed at the end of one track and the other peripheral edge is fixed to the end of the other track, the seal structure being slid into the seal groove. The peripheral edge of the seal member in contact with the seal lip is provided with a protrusion on the inner surface of the seal lip. The protrusion is normally not in contact with the inner surface of the seal groove and is partitioned by the seal member. When a pressure difference is generated between the inside and the outside of the bearing and the seal lip is pushed inward, the seal lip contacts the inner surface of the seal groove. The structure is such that an air passage that connects the inside of the bearing with the outside of the bearing is formed by partially elastically deforming the bearing. The grease is based on a base grease consisting of a base oil and a thickener. The additive contains at least one aluminum-based additive selected from aluminum powder and aluminum compound, and the mixing ratio of the aluminum-based additive is 0.05 to 10% by weight with respect to 100 parts by weight of the base grease. It is a part.

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 rolling bearing of the present invention is provided with the above-described seal structure, so that it is possible to always ensure sealing performance and prevent grease leakage and to use grease containing an aluminum-based additive. The aluminum compound added to the grease reacts on the new metal surface exposed by wear, and an aluminum film is formed on the rolling surface of the bearing along with iron oxide, resulting in peculiar delamination due to hydrogen embrittlement etc. found in bearings used in various industrial machines. Occurrence can be suppressed. As a result, it is possible to dramatically improve the life of the bearing.
Further, the above seal structure can prevent an increase in torque due to the adsorption of the seal, and a stable bearing function can be obtained.
As described above, the grease-filled rolling bearing according to the present invention can effectively prevent brittle peeling on the rolling surface and has an excellent bearing life, and can prevent the sticking phenomenon of the seal. It can be suitably used as a rolling bearing for automobile electrical parts such as pulleys and electric fan motors and auxiliary machines.

  In the grease-enclosed rolling bearing of the present invention, the seal structure that prevents the adsorption phenomenon while ensuring the sealing performance at all times is provided with a seal lip at the periphery of the seal member that is in sliding contact with the seal groove, and a protrusion on the inside of the seal lip. When the seal lip is pushed inward due to a pressure difference between the inside of the bearing and the outside of the bearing that is partitioned by the seal member, the protrusion is normally not in contact with the inner surface of the seal groove. Is in contact with the inner surface of the seal groove, and by the contact of this protrusion, the seal lip in the vicinity of the contact is partially elastically deformed to form an air passage that connects the inside of the bearing and the outside of the bearing. It is a configuration.

  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 the seal structure of the grease-enclosed rolling bearing that is in sliding contact with the seal groove formed at the end and the other peripheral edge is fixed to the end of the other raceway, the peripheral edge of the seal member that is in sliding contact with 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. A pressure difference is generated between the inside of the bearing partitioned by the seal member and the outside of the bearing, and the seal lip is When pushed inward, it comes into contact with the inner surface of the seal groove, and the contact between the protrusions causes the seal lip in the vicinity of the contact to be partially elastically deformed to communicate the inside of the bearing with the outside of the bearing. Air passage than that employing the configuration as 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.

  Also, if a structure is adopted 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, an adsorption phenomenon When this 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.

An embodiment of a grease-filled rolling bearing according to the present invention will be described in detail with reference to FIGS. As shown in FIG. 1, the grease-filled rolling bearing of this embodiment includes an inner ring 1 and an outer ring 2, a ball 3 that is provided to freely roll between the inner ring 1 and the outer ring 2, and an inner ring 1 and an outer ring 2. It is comprised from the cyclic | annular sealing member 4 fitted to an axial direction both ends. Grease 24 is sealed around at least the balls 3.
An inner ring raceway 5 on which the ball 3 rolls is provided on the outer diameter surface of the inner ring 1, and an outer ring raceway 6 facing the inner ring raceway 5 is provided on the inner diameter surface of the outer ring 2. A circumferential seal groove 7 is formed on both sides of the inner ring raceway 5, and a seal member locking groove 8 is formed on the inner diameter surface of the outer ring 2 facing the seal groove 7. The outer peripheral edge 9 of the seal member 4 is locked in the seal member locking groove 8.

  The seal member 4 is obtained by reinforcing an elastic body 11 made of synthetic rubber or the like with a cored bar 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. A main lip 15 is formed which extends and whose tip is in sliding contact with the inner surface 16 of the seal groove 7.

  As shown in FIGS. 2A and 2B, 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. The protrusion 17 is provided on the inner side of the main lip 15 at one or a plurality of locations along the tip (the inner peripheral edge of the seal member 4).

  When the sealing member 4 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. 2). (See (b)). In this state, the protrusion 17 does not come into contact with 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 is moved to the inside. 2, the protrusion 17 provided on the main lip 15 contacts the inner 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.

  If the pressure difference between the inside and outside of the bearing is large and the protrusion 17 is crushed by 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 contact resistance of the tip portion of the projection 17 becomes larger than the sliding contact resistance of the tip portion 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. 3C, the front end portion of the main lip 15 (inner peripheral edge of the seal member 4) 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. 4 (a), a protrusion 20 protruding over the entire circumference along the tip sliding contact portion is formed on the inner surface of the main lip 15, and the protrusion 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. 4B, 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 dividing the ridge 20 by reaching the inner surface of the main lip 15. .

  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. 4C, 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.

  Also, 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 contact resistance of the tip of the ridge 20 becomes larger than the sliding contact 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 front end portion of the main lip 15 slides, as shown in FIG. 5C, the front end portion of the main lip 15 (inner peripheral edge of the seal member 4) 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 grease-enclosed rolling bearing of the present invention is characterized by using grease containing an aluminum-based additive in addition to the above seal structure.
The aluminum-based additive used in the present invention is at least one selected from an aluminum powder and an 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-based additives may be added to grease by mixing one type or two types.
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 the amount exceeds 10 parts by weight, the anti-peeling effect does not improve 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, -Hydrocarbon synthetic oil such as α-olefin oil, alkylnaphthalene, alicyclic compound, etc., 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.

  Occurrence of specific peeling due to hydrogen embrittlement on the rolling surface of the bearing can be suppressed by the seal structure applied to the grease-filled rolling bearing of the present invention and the sealing of the grease containing the aluminum-based additive. For this reason, ball bearings, cylindrical roller bearings, tapered roller bearings, spherical roller bearings, needle roller bearings, thrust cylindrical roller bearings, thrust tapered roller bearings, thrust needle roller bearings, thrust spherical roller bearings, etc. The grease life can be improved, and the life of the grease-filled rolling bearing can be extended.

As an example of the grease-filled rolling bearing of the present invention, the grease of the present invention is sealed in a deep groove ball bearing having the seal structure of the present invention, left in a 150 ° C. atmosphere for 15 minutes, and then left at room temperature for a certain period of time. The starting torque was measured and found to be 1 N · cm. On the other hand, when the grease was sealed in the same deep groove ball bearing having a conventional seal structure and the starting torque was measured under the same conditions, it was 6 N · cm.
In addition, a bearing temperature of about 150 ° C is assumed for electrical accessories, especially alternators. In this case, the bearing structure of the present invention capable of reducing the starting torque is expected to have a bearing temperature of about 140 ° C., and the conventional seal structure is expected to have a bearing temperature of about 160 ° C., resulting in a temperature difference of 20 ° C.
If the grease life is in accordance with the Arrhenius law and the activation energy of 30-40 kcal / mol, which is the activation energy of general organic matter, is the activation energy of the grease, this temperature difference of 20 ° C will be approximately four times the grease life.

  The grease containing the aluminum powder and the like used in the present invention has a peeling occurrence life described below of 2.5 times or more as compared with the conventional grease. Therefore, when combined with the seal structure used in the present invention, the bearing life of the grease-filled rolling bearing can be greatly improved.

Peeling life:
The following grease was sealed in a rolling bearing that supports a rotating shaft that supports a pulley around which a rotating belt of an alternator, which is an example of an electrical equipment / auxiliary machine, is wound, and used as a test bearing. A rapid acceleration / deceleration test was performed on this test bearing. The rapid acceleration / deceleration test conditions are such that the operating load is set to 1960 N for the test bearing attached to the end of the rotating shaft, the rotation speed is 0 rpm to 18000 rpm, and a current of 0.1 A flows in the test bearing. The test was conducted at Then, abnormal peeling occurred in the test 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 500 hours.

Grease used in the present invention:
Base oil Synthetic hydrocarbon oil (Nippon Steel Chemical Co., Shinflud 601) 15 parts by weight Thickener Urea (p-toluidine 10.1 parts by weight + MDI 11.9 parts by weight)
Antioxidant Hindered phenol 1 part by weight Aluminum powder 1 part by weight Stripping life 500 hours or more

Conventional grease:
Base oil Synthetic hydrocarbon oil (Nippon Steel Chemical Co., Shinflud 601) 15 parts by weight Thickener Urea (p-toluidine 10.1 parts by weight + MDI 11.9 parts by weight)
Antioxidant Hindered phenol 1 part by weight Aluminum powder No compounding Peeling life 200 hours

  The grease-filled rolling bearing according to the present invention can effectively prevent brittle peeling on the rolling surface and has a long bearing life. Therefore, an automotive electrical component such as an alternator, an electromagnetic clutch for a car air conditioner, an intermediate pulley, an electric fan motor, and an auxiliary machine It can utilize suitably as rolling bearings.

It is sectional drawing of the grease enclosure rolling bearing of embodiment. (A) The cross-sectional perspective view which shows the protrusion provided in the lip same as the above, (b) The cross-sectional perspective view which shows the normal state of the seal lip same as the above, (c) The cross-sectional perspective view which shows the adsorption state of the 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 perspective view showing a normal state of the above-described seal lip, and (c) an adsorbed state of the above-described seal lip. FIG. (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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Ball 4 Seal member 5 Inner ring raceway 6 Outer ring raceway 7 Seal groove 8 Seal member locking groove 9 Outer peripheral edge 10 Core metal 11 Synthetic rubber 12 Seal lip 13 Waist part 14 Dustrip 15 Main lip 16 Inner side face 17 Projection 18 Air passage 19 Air passage 20 Projection 21 Notch groove 22 Air passage 23 Air passage 24 Grease

Claims (6)

A ball is inserted between both races of the inner ring and the outer race and filled with grease, and both end faces of both raceways are closed with a seal member, and the seal member is a seal formed on one end of one raceway. A grease-enclosed rolling bearing having a seal structure in sliding contact with the groove and having the other peripheral edge fixed to the end of the other track,
In this seal structure, the peripheral edge 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 rolling 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.   2. The grease-filled rolling 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.   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. 1. A grease-filled rolling bearing according to 1.   4. The grease-filled rolling bearing according to claim 1, wherein the aluminum compound is at least one compound selected from aluminum carbonate and aluminum nitrate.   The grease-enclosed rolling bearing according to any one of claims 1 to 4, wherein the thickener is a urea-based thickener.   The grease-enclosed rolling 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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