JP2011196422A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing capable of taking a countermeasure against fragility-separation so as not to carry an electric current to rolling travel surfaces of inner-outer rings, by preventing reduction in electric conductivity between the inner-outer rings and a seal member, by preventing the formation of an oil film in a seal sliding part, by preventing the movement of grease to the seal sliding part.SOLUTION: In the rolling bearing, a plurality of rolling elements 3 are interposed between the rolling travel surfaces 1a and 2a of the inner-outer rings 1 and 2, and the seal member 5 is arranged in the outer ring 2, for blocking up a bearing space between the inner-outer rings 1 and 2 when a lip part 5c slidingly contacts with the inner ring 1. The seal member 5 is formed of a conductive construction material, and a grease leakage checking part is arranged in a cage 4 for holding the rolling elements 3, for checking flowing of the grease in the bearing space to a sliding contact part between the seal member 5 and the inner ring 1.

Description

  The present invention relates to, for example, a bearing disposed in a belt transmission mechanism, and more particularly, to a rolling bearing used for supporting shafts of a pulley, an alternator / compressor, etc. used in a timing belt of an automobile engine, a belt for driving an auxiliary machine, and the like. .

  Among the rolling bearings according to the prior art, the current-carrying bearing is, for example, a seal member that closes the bearing space is made of a material having good conductivity, a fixing portion that fixes the seal member to a bearing outer ring is provided, and the bearing inner ring What provided the seal | sticker sliding part which slides the lip | rip part of a sealing member is used (patent document 1). In addition, the current-carrying bearings are generally used in places where there is a possibility of electric corrosion, and are not used much around the engine.

Japanese Utility Model Publication No. 4-124331

As countermeasures against brittle delamination in bearings used for shaft support of automobile engine timing belts, auxiliary machine drive belts, alternators and compressors, etc. Measures such as curvature and internal clearance are taken. The “brittle exfoliation” refers to exfoliation due to hydrogen embrittlement, which is different from the exfoliation due to normal metal fatigue, and there is a problem that the life of the bearing is shortened due to the brittle exfoliation.
However, in some cases, the countermeasure against brittle peeling as described above cannot prevent the grease from moving to the seal sliding portion of the bearing inner ring. When the grease moves to the seal sliding portion, an oil film is formed on the seal sliding portion, thereby reducing the conductivity of the seal member.

  The purpose of this invention is to prevent grease from moving to the seal sliding part, and to prevent the formation of an oil film on the seal sliding part, thereby preventing a decrease in conductivity between the inner and outer rings and the seal member, Accordingly, it is an object of the present invention to provide a rolling bearing capable of taking measures against brittle peeling by preventing the rolling surfaces of the inner and outer rings from being energized.

  The rolling bearing of the present invention is a rolling bearing in which a plurality of rolling elements are interposed between the rolling surfaces of the inner and outer rings, and a lip portion is in sliding contact with the inner ring to seal the bearing space between the inner and outer rings. The seal member is made of a conductive material, and the cage that holds the rolling element is provided with a grease leakage prevention portion that prevents the grease in the bearing space from flowing into the sliding contact portion between the seal member and the inner ring. It is characterized by that.

  According to this configuration, by using a conductive material for the seal member, it is possible to improve the electrical conductivity of the outer ring, the seal member, and the inner ring, and to reduce the current supplied to the rolling part of the inner and outer rings. Further, since the grease is provided with the grease leakage preventing portion for preventing the grease from flowing in the sliding contact portion between the seal member and the inner ring, the oil film can be prevented from being formed on the sliding contact portion. Therefore, it is possible to prevent brittle peeling by preventing a decrease in conductivity between the inner and outer rings and the seal member and preventing the rolling surfaces of the inner and outer rings from being energized. Therefore, it is possible to prevent a decrease in bearing life due to brittle peeling.

The rolling element is a ball, and the grease leakage prevention portion is provided with a concave portion extending from the opening edge on the inner diameter side of the cage to the outer diameter side of the cage on the inner surface of a pocket that holds the ball of the cage. May be.
In a ball bearing using a cage with a conventional general shape with a spherical pocket inner surface, when the ball, which is a rolling element, rolls on the inner ring rolling surface, the thickness of grease on the inner ring rolling surface is determined by Hertz contact. From the center to the axial direction, the grease thickness on the ball surface is also symmetric from the center of Hertz contact to the inner ring rolling surface width. When the grease adhering to the ball surface enters the cage by the rotation of the ball, the grease is scraped off by the cage. The scraped grease adheres to the cage, but part of the grease also adheres to the inner ring shoulder as the amount of grease increases. When the grease adhering to the shoulder portion of the inner ring increases, the grease adheres so as to ride up near the central portion of the pocket of the rotating cage. As the amount of grease that rides on increases, it comes in contact with the grease on the shoulder of the inner ring, and the grease adheres to the inner ring seal groove. This is the movement of grease in a general steel sheet punching cage. Further, in this general-shaped cage, the grease adhered to the central portion of the cage pocket adheres to the inner surface of the seal. As a result, grease that hardly contributes directly to lubrication remains on the inner surface of the seal. In addition, grease shear occurs between the cage pocket and the seal inner surface, and the bearing torque increases.

  On the other hand, since the inner surface of the pocket of the cage is concave spherical, and the inner surface of the concave spherical pocket is provided with a recess extending from the opening edge on the inner diameter side of the cage to the outer diameter side of the cage, the inner ring shoulder portion Grease does not adhere to the surface. That is, since a recess is provided at the opening edge on the inner diameter side of the cage, which is the position where the grease adheres most to the ball, scraping of the surface of the ball is reduced, and the amount of grease collected on the inner diameter surface of the cage is reduced. Therefore, it is possible to prevent the grease from flowing to the sliding contact portion between the seal member and the inner ring.

  The rolling element is a ball, and the cage is in a ring shape having pockets for holding the ball at a plurality of locations in the circumferential direction, and two annular cage halves are stacked facing each other in the axial direction. These cage halves have a spherical shell-shaped plate portion whose inner circumference forms half of each pocket, and a flat plate portion that is a portion between adjacent pockets alternately arranged in the circumferential direction. The grease leakage prevention portion is a portion located at an outer diameter surface portion at least at the shoulder height on both sides of the rolling surface of the inner ring in the inner diameter side portion from the ball arrangement pitch circle in the spherical shell-shaped plate portion. The plate thickness may be smaller than the plate thickness of the flat plate portion.

  Also in this case, since grease does not adhere to the shoulder portion of the inner ring, it is possible to prevent the grease from flowing to the sliding contact portion between the seal member and the inner ring. In addition, the strength of the cage is reduced by making the reference plate thickness that is the plate thickness of the outer diameter side portion of the flat plate portion of the cage half and the ball arrangement pitch circle of the spherical shell plate portion equal to the conventional one. Therefore, it is possible to prevent the grease from flowing into the sliding contact portion between the seal member and the inner ring. Since this cage can be formed with a pocket shape in contact with the balls in the same manner as the conventional one, the interference force between the cages does not increase due to the increase of the movable range of the cage.

The rolling element is a ball, and the grease leakage prevention portion has a radial clearance between the outer diameter surface of the inner ring and the inner diameter surface of the cage that is equal to or larger than a value obtained by multiplying the diameter of the ball by 0.09. Also good. In this case, a clearance for grease accumulated on the inner diameter side of the cage is provided. Thereby, the grease in the bearing space can be prevented from flowing to the sliding contact portion between the seal member and the inner ring.
The radial clearance may be equal to or less than a value obtained by multiplying the diameter of the ball by 0.36. In consideration of the strength of the cage, the shoulder diameters of the inner and outer rings, the amount of movement of the cage, and the like, it is desirable that the radial clearance is not more than a value obtained by multiplying the diameter of the ball by 0.36.

  A seal groove is formed in a circumferential direction on the outer diameter surface of the inner ring, and a shoulder portion protruding toward the outer diameter side is formed between the seal groove and the end portion of the inner ring, and an outer ring inner diameter surface facing the seal groove is formed. A main lip that fixes an outer peripheral edge of the seal member, contacts and slides on a groove wall of the seal groove, and a labyrin slip disposed radially outward of the shoulder; The main lip may be provided with an inner peripheral surface that faces the seal groove, and an inclined surface that increases in diameter toward the tip of the labyrin slip may be provided on the inner peripheral side of the labyrin slip.

  In this case, since the main lip contacts and slides against the groove wall of the seal groove, grease inside the bearing is prevented from leaking into the seal groove, and in addition, foreign matter and muddy water are not allowed to enter the bearing inside. Can be prevented. Further, the muddy water accumulated in the seal groove moves along the inclined surface of the labyrin slip from the inner peripheral surface of the main lip by centrifugal force due to rotation of the seal member, etc., and is discharged outside the bearing.

  A constricted portion that is connected to the outer diameter side from the base end portion of the main lip and the labyrin slip and is formed thinner than the axial thickness of the main lip and the labyrin slip may be provided in the seal member. In this case, since the constricted portion is elastically deformed in the axial direction, the main lip connected to the constricted portion maintains the followability to the groove wall of the seal groove. Therefore, the grease inside the bearing can be more reliably prevented from leaking into the seal groove.

The consistency of the grease sealed in the bearing space may be less than 389. The “consistency” represents the hardness of grease and corresponds to the viscosity of oil. This “consistency” indicates the penetration depth when a metal cone is penetrated by its own weight at 25 ° C., and is expressed by a value obtained by multiplying 10 times.
The applicant examined the relationship between consistency and grease leakage. In this test, the consistency was changed by increasing the proportion of base oil in the grease. In this test, grease leakage was confirmed when the consistency of the grease was 389 or more. Accordingly, the upper limit value of the grease consistency is preferably 389.

  The rolling bearings of these inventions may be applied to pulley bearings or automotive electrical accessory bearings. The rolling bearing can take more reliable measures against brittle peeling than those of the prior art, and thus can more reliably prevent a decrease in bearing life due to brittle peeling in pulley bearings and automotive electrical equipment bearings. it can.

  The rolling bearing of the present invention is a rolling bearing in which a plurality of rolling elements are interposed between the rolling surfaces of the inner and outer rings, and a lip portion is in sliding contact with the inner ring to seal the bearing space between the inner and outer rings. The seal member is made of a conductive material, and the cage that holds the rolling element is provided with a grease leakage prevention portion that prevents the grease in the bearing space from flowing into the sliding contact portion between the seal member and the inner ring. Therefore, the grease movement to the seal sliding part is prevented, and the oil film is not formed on the seal sliding part, thereby preventing a decrease in conductivity between the inner and outer rings and the seal member. It is possible to take measures against brittle peeling by preventing the rolling surface of the ring from being energized.

It is sectional drawing of the rolling bearing which concerns on one Embodiment of this invention. (A) is sectional drawing which expands and shows the principal part of the sealing member of the rolling bearing, (B) is sectional drawing which expands and shows the principal part of the sealing member further. It is a perspective view of the holder | retainer of the rolling bearing. It is a perspective view showing the holder half body which is a structural member of the holder. It is a partial expansion perspective view which simplifies and shows a pocket shape about a part of the cage half. (A) is a partial enlarged perspective view highlighting an example of the inner surface of the spherical shell plate portion in the cage half, and (B) is a perspective view showing a state in which a virtual cylinder is added to the perspective view. (A) is a partial enlarged perspective view highlighting another example of the inner surface of the spherical shell plate in the cage half, (B) is a perspective view showing a state in which a virtual cylinder is added to the perspective view. is there. It is explanatory drawing of the result of the grease leak test of the bearing incorporating the cage | basket of the structure shown in FIG. It is explanatory drawing of the result of the grease leak test of the bearing incorporating the cage | basket of the structure shown in FIG. It is explanatory drawing of the result of the grease leak test of the bearing incorporating the general iron plate punching cage. It is a figure showing the test result of the relationship between the consistency of grease, and the amount of grease leakage. It is sectional drawing which fractured | ruptured partially the rolling bearing which concerns on other embodiment of this invention. It is a partial expansion perspective view which shows the spherical shell-shaped board part in the holder | retainer half body of the holder | retainer integrated in the same bearing. It is a partial expanded sectional view of the cage | basket of the rolling bearing which concerns on other embodiment of this invention. It is a front view of the retainer. It is explanatory drawing of the radial direction clearance gap between the outer diameter surface of the inner ring | wheel in the rolling bearing, and the internal diameter surface of a holder | retainer. It is a figure which shows the test result of the grease leak prevention effect of the rolling bearing concerning one Embodiment of this invention. It is a front view of the holder | retainer in the sealing type rolling bearing concerning other embodiment of this invention. It is explanatory drawing of the radial direction clearance gap between the outer diameter surface of the inner ring | wheel in the rolling bearing, and the internal diameter surface of a holder | retainer. It is sectional drawing which provided the rolling bearing concerning one Embodiment of this invention in the idler pulley. It is sectional drawing which provided the rolling bearing concerning one Embodiment of this invention in the alternator.

An embodiment of the present invention will be described with reference to FIGS. The rolling bearing according to this embodiment is a deep groove ball bearing. As shown in FIG. 1, this rolling bearing has a plurality of rolling elements 3 interposed between rolling surfaces 1 a and 2 a of an inner ring 1 and an outer ring 2, and a retainer 4 that holds these rolling elements 3 is provided. A seal member 5 that closes a bearing space formed between 1 and 2 is provided on the outer ring 2. A ball is applied as the rolling element 3. A predetermined degree of grease is sealed in the bearing space.
The cage 4 is provided with a later-described grease leakage prevention portion that prevents the grease in the bearing space from flowing into the sliding contact portion Sb between the seal member 5 and the inner ring 1.

As shown in FIGS. 1 and 2, a circumferential seal groove Sm is formed on the left and right sides of the rolling surface 1a in the outer diameter surface 1D of the inner ring 1, and the outer ring inner diameter surface facing each seal groove Sm is engaged. A stop groove 2b is formed. The outer peripheral edge portion of the seal member 5 is press-fitted and fixed in the locking groove 2 b of the outer ring 2.
The seal groove Sm of the inner ring 1 is formed by a groove wall Sma on the rolling surface side of the inner ring 1, a bottom surface Smb, and a groove wall Smc on the shoulder 1b side. The groove wall Smc is inclined outward in the axial direction, and is formed continuously with the outer peripheral surface of the shoulder portion 1b.
The groove wall Sma is referred to as “track-side groove wall Sma”, and the groove wall Smc is referred to as “shoulder-side groove wall Smc”.

The seal member 5 will be described.
As shown in FIG. 1 and FIG. 2, the seal member 5 is formed of a contact seal, and has a metal core 5a and an elastic member 5b. A main lip Lm and a labyrin slip Lb are formed on the inner peripheral portion of the elastic member 5b. Is provided. The seal member 5 is obtained by reinforcing an elastic member 5b made of conductive rubber with a cored bar 5a. As the conductive rubber used for the elastic member 5b, for example, a material having improved conductivity such as nitrile, acrylic, fluorine and the like can be adopted. As the seal material, nitrile, acrylic, fluorine, which has been conventionally used as a bearing seal, is mixed with or coated with a conductive carbon or the like to improve conductivity. Therefore, any material can be used as long as it has conductivity.

  The seal member 5 is formed with a constricted portion 5ba having a small thickness at a portion of the elastic member 5b on the inner peripheral portion thereof. The constricted portion 5ba is connected to the outer diameter side from the base end portions of a main lip Lm and a labyrin slip Lb, which will be described later, and is formed thinner than the axial thickness of the main lip Lm and the labyrin slip Lb. In other words, a lip portion 5c is provided at the inner peripheral end of the constricted portion 5ba, and this lip portion 5c is in contact with the main lip Lm in contact with the track-side groove wall Sma of the seal groove Sm and the radial direction of the shoulder portion 1b. And a labyrinth slip Lb disposed outward.

The main lip Lm faces the track-side groove wall Sma of the seal groove Sm, and has an inclined wall surface Lma that expands outward, and an inner circumference that is located radially inward of the inclined wall surface Lma and faces the bottom surface Smb of the seal groove Sm. It has surface Lmb, and tip part Lmc which makes inclined wall surface Lma and inner peripheral surface Lmb continue.
As shown in FIG. 1, when the outer peripheral edge portion of the seal member 5 is press-fitted and fixed in the locking groove 2b of the outer ring 2, as shown in FIG. 2, the tip portion Lmc of the main lip Lm is a track of the seal groove Sm. It is in sliding contact with the side groove wall Sma. The main lip Lm is provided at the tip of the constricted portion 5ba formed to be thin, and the constricted portion 5ba is elastically deformed in the axial direction of the arrow A1 in FIG. Followability to the side groove wall Sma is maintained. Thereby, it can prevent more reliably that the grease inside a bearing leaks into seal groove Sm.

  The labyrinth slip Lb faces the range from the shoulder 1b to the shoulder side groove wall Smc of the seal groove Sm, and the labyrinth seal Ls is formed. On the inner peripheral portion of the labyrinth slip Lb, there is provided an inclined surface Lba whose diameter is reduced inward in the axial direction, in other words, an inclined surface Lba whose diameter is increased toward the tip of the labyrinth slip Lb. The inclined surface Lba is set so that the inclination angle α1 with respect to the outer peripheral surface of the shoulder 1b of the inner ring 1 is not less than 10 degrees and not more than 40 degrees. When the inclination angle α1 is set in this way, muddy water or the like adhering to the inclined surface Lba when the rolling bearing rotates the outer ring is axially outward along the inclined surface Lba by the centrifugal force due to the rotation of the seal member 5. And is discharged to the outside of the bearing.

  When the inclination angle α1 is less than 10 degrees, the centrifugal force due to the rotation of the seal member 5 does not sufficiently act on the muddy water adhering to the labyrin slip Lb, so that the muddy water is difficult to be discharged. When the inclination angle α1 exceeds 40 degrees, the gap between the outer peripheral surface of the shoulder portion 1b and the inclined surface Lba of the labyrin slip Lb becomes wide, and the sealing performance by the labyrinth Ls decreases. For this reason, the inclination angle α1 is set to 10 degrees or more and 40 degrees or less.

The tip of the labyrinth slip Lb is provided near the shoulder side wall Smc of the seal groove Sm. Therefore, the distance that the muddy water adhering to the labyrin slip Lb moves on the inclined surface Lba by the centrifugal force due to the rotation of the seal member 5 is shortened, and the muddy water accumulated in the seal groove Sm is easily discharged.
A step portion Ds is provided between the inner peripheral surface Lmb of the main lip Lm and the inclined surface Lba of the labyrinth slip Lb. The step portion Ds is provided so as to protrude toward the shoulder portion side groove wall Smc of the seal groove Sm. Thereby, since the inner peripheral surface Lmb of the main lip Lm is continuously formed through the step portion Ds and the inclined surface Lba of the labyrin slip Lb, the muddy water accumulated in the seal groove Sm is caused by the rotation of the seal member 5. It is easy to be discharged to the outside of the bearing along the inclined surface Lba of the labyrinth slip Lb by centrifugal force.

  Further, when the step portion Ds is provided so as to protrude toward the shoulder side groove wall Smc, a constricted portion is formed between the outer peripheral edge portion of the inner peripheral surface Lmb of the main lip Lm and the shoulder side groove wall Smc of the seal groove Sm. Is done. With this narrowed portion, the sealing performance by the labyrinth seal Ls can be secured. Since a narrowed portion is also formed between the peak portion Yd at the boundary between the seal groove Sm and the shoulder portion 1b and the inclined surface Lba of the labyrin slip Lb, the sealing performance by the labyrinth seal Ls can be further secured.

プーリ回転速度は、運転開始後６０００ｒ／ｍｉｎまで上げ、この６０００ｒ／ｍｉｎを５時間維持する。この５時間経過後１０５００ｒ／ｍｉｎまでプーリ回転速度を上げて同回転速度を３００時間維持した後、１２０００ｒ／ｍｉｎまでプーリ回転速度を上げて７００時間維持する。 A brittle peel test was performed on a seal built-in product in which the seal member or the like according to this embodiment was incorporated in a ball bearing.
The test conditions are as shown in Table 1 below.

The pulley rotation speed is increased to 6000 r / min after the start of operation, and this 6000 r / min is maintained for 5 hours. After 5 hours, the pulley rotational speed is increased to 10500 r / min and maintained at the same rotational speed for 300 hours, and then the pulley rotational speed is increased to 12000 r / min and maintained for 700 hours.

この試験結果から、シール部材５を導電性の材質とすることで、外輪２−シール部材５−内輪１の通電性を良くし、内外輪１，２の転走部１ａ，２ａへの通電を減少させることが可能となり、脆性剥離対策が期待できる。 A standard seal product including a non-conductive elastic member and the seal built-in product according to this embodiment (referred to as a current-carrying seal built-in product) were tested under the test conditions, and the results shown in Table 2 below were obtained. When the test product is peeled off, the vibration value due to rotation during operation becomes high.

From this test result, the seal member 5 is made of a conductive material, so that the outer ring 2-seal member 5-the inner ring 1 is improved in electrical conductivity, and the rolling parts 1a, 2a of the inner and outer rings 1, 2 are energized. It can be reduced, and brittle peeling countermeasures can be expected.

The cage 4 will be described.
As shown in FIG. 3, the cage 4 has a ring shape having pockets 46 for holding the balls at a plurality of locations in the circumferential direction, and the inner surface of each pocket 46 has a concave spherical shape. The retainer 4 is formed by joining two annular retainer halves 47 shown in a perspective view in FIG. 4 so as to face each other in the axial direction and joining them together by a rivet 49 inserted through a rivet hole 48. Composed. Each of these cage halves 47 has a plurality of spherical shell-shaped plate portions 46A having a partial spherical shell shape whose inner surface forms half of the pocket 46, and a flat plate portion 47a serving as a portion between adjacent pockets 46; The spherical shell plate portions 46A are alternately arranged in the circumferential direction. The spherical shell-shaped plate portion 46A is a part that becomes a part of the spherical shell, in other words, a countersink-shaped bulging portion in which both the inner and outer surfaces are spherical. The projected shape of the cage half 47 in the axial direction is a ring shape whose radial width is constant over the entire circumference.

  A part of the cage half 47 is enlarged and shown in a perspective view in FIG. FIG. 5 is a diagram in the case where the pocket inner surface is a monotonous spherical surface in a portion corresponding to FIG. In FIG. 5, a portion A indicated by a two-dot chain line indicates a circumferential band in which the flat plate portions 47 a in the cage half 47 are arranged in the circumferential direction. The spherical shell plate portion 46A, which is a half of the pocket 46, is formed at a portion of the circumferential band A that is not the flat plate portion 47a. One side portion of the spherical shell-shaped plate portion 46A in the drawing is an inner diameter side portion 46Ai of the cage 45, and the other side portion of the spherical shell-shaped plate portion 46A is an outer diameter side portion 46Ao of the cage 45.

The inner surface of the pocket 46 of the cage 4 of this embodiment is provided with a recess 50 that extends from the opening edge on the inner diameter side of the cage toward the outer diameter side of the cage as a grease leakage prevention portion. That is, on the inner surface of the spherical shell-shaped plate portion 46A in the pocket 46 of the cage 4, as shown in FIG. 6, in the inner diameter side portion 46Ai of the cage 4, from the opening edge on the inner diameter side of the cage, A recess 50 extending in the radial direction is provided. The sectional shape of the inner surface of the recessed portion 50 along the circumferential direction of the cage (that is, the sectional shape taken along the plane perpendicular to the central axis of the cage) is smaller than the curvature radius Ra of the concave spherical surface serving as the inner surface of the pocket 46. The arc shape has a radius Rb.
The inner surface shape of the recessed portion 50 is a cylindrical surface shape substantially along the surface of the virtual cylinder V centered on the straight line L in the radial direction of the cage 4 as shown in FIG. The virtual cylinder V may be the surface of a grindstone that processes the recess 50. The recessed portion 50 extends from the opening edge on the inner diameter side of the cage to the ball arrangement pitch circle PCD in the radial direction of the cage, and gradually decreases, that is, gradually, from the inner diameter edge of the cage to the ball arrangement pitch circle PCD. The shape is shallow and narrow. In this embodiment, the recess 50 extends to the ball arrangement pitch circle PCD. However, the depression 50 may extend slightly to the outer diameter side of the cage from the ball arrangement pitch circle PCD, or may slightly extend to the ball arrangement pitch circle PCD. You may not reach it. The ball arrangement pitch circle PCD is also called a pocket PCD.

  The depth of the recess 50 is such that the distance Rc from the center O46 of the concave spherical surface of the pocket inner surface to the deepest position of the recess 50 is at least 1.05 times the radius of the ball (just 1.05 times. Is preferable). The radius of curvature Ra of the concave spherical surface that is the inner surface of the pocket 46 is slightly larger than the radius of the ball, and is less than 1.05 of the radius of the ball.

FIG. 7 shows another shape example of the inner surface of the pocket 46 of the cage 4.
In this example, a recess 50A serving as a grease leakage prevention portion provided on the inner diameter side portion 46Ai of the inner surface of the spherical shell-shaped plate portion 46A in the pocket 46 is formed at the center OW46 in the cage circumferential direction at the opening edge of the pocket 46. Two locations are located on both sides. The inner surface shape of each recess 50A is such that the cross-sectional shape along the circumferential direction of the cage (that is, the cross-sectional shape taken along a plane perpendicular to the cage central axis) is larger than the radius of curvature Ra of the concave spherical surface serving as the inner surface of the pocket 46. It has an arc shape with a small radius of curvature RAb, and in detail, as shown in FIG. 5B, it has a cylindrical surface shape substantially along the surface of each virtual cylinder VA centered on the radial straight line LA of the cage 4. is there. The recessed portion 50A extends from the opening edge on the cage inner diameter side to the vicinity of the ball arrangement pitch circle PCD in the radial direction of the cage, and gradually decreases from the cage inner diameter edge toward the ball arrangement pitch circle PCD. The shape gradually becomes shallower and narrower.

  The positions of the two recessed portions 50A are, for example, two symmetrical places where the circumferential orientation angle with respect to the center OW46 in the circumferential direction of the cage at the opening edge of the pocket 46 is 40 ° ± 15 °. Also in this example, the depth of the recess 50A is such that the distance RAc from the center O46 of the concave spherical surface of the pocket inner surface to the deepest position of the recess 50A is 1.05 times the radius of the ball or more. Preferred (just 1.05 times).

In this embodiment, the number of the recessed portions 50A is two, but may be three or more.
The cross-sectional shape along the circumferential direction of the cage of the recesses 50 and 50A as the grease leakage prevention portion is not limited to the shape of each example of FIGS. 6 and 7, but a partial oval shape, a rectangular groove shape, a trapezoidal groove shape, Any other cross-sectional shape may be used. Further, the cross-sectional shape of the recesses 50 and 50A may be asymmetric with respect to the center of the recess.
The inner surface shape of the pocket 46 is not limited to a spherical shape, and may be any shape as long as the inner diameter side portion of the ball arrangement pitch circle PCD becomes a smaller diameter as it approaches the cage inner diameter side opening edge. The portion on the outer diameter side of the PCD may be a cylindrical surface, and the portion on the inner diameter side may be a conical surface.

When manufacturing each said holder | retainer, for example, a steel plate is pressed and a ring-shaped metal strip is punched out. Next, a press die having a convex press die that forms the inner surface of the spherical shell plate portion 46A of the cage half 47 and a concave press die that forms the outer surface of the spherical shell plate portion 46A. A die set is prepared, and the ring-shaped metal strip is sandwiched between the convex press die and the concave press die, and the cage half 47 is press-molded. This press molding may be performed in two stages of rough pressing and finishing pressing, or may be performed once.
The two retainer halves 47 obtained in this way are overlapped, and the portion where the flat plate portions 47 a of the retainer halves 47 overlap is joined by a rivet 49 to form the retainer 4.

8 to 10 show test results for confirming the grease adhesion state. In this test, a ball bearing incorporating the cage 4 of the embodiment of FIG. 6 and the embodiment of FIG. 7 and a ball bearing incorporating a general steel plate punching cage are designated as a bearing identification number “6203”, a seal The test was performed under the test conditions of none, outer ring rotation, rotation speed 3600 min ⁻¹ , axial load 39 N, and operation time 5 seconds. From this test result, it is confirmed that grease is adhered to the inner ring seal groove in a ball bearing incorporating a general steel plate punched cage, but no grease is adhered to a ball bearing incorporating the cage 4 of this embodiment. did.

  Further, a contact seal (NTN LU seal) was assembled to each of the ball bearings, and a grease leakage frequency confirmation test was also conducted. In this test, only the operation time was changed to 15 minutes among the test conditions. As a result, 9 out of 10 grease leaks in the conventional cages, whereas none of the bearings incorporating the cages of the embodiments had any grease leaks. .

  As can be seen from these test results, in the ball bearing incorporating the retainer 4 of this embodiment, the recesses 50 and 50A are provided on the inner surface of the pocket 46 of the retainer 4 as a grease leakage prevention portion. It is possible to eliminate the adhesion of grease to the surface. That is, since the recesses 50 and 50A that open at the opening edge on the inner diameter side of the cage, which is the position where the grease adheres most to the ball, are provided, scraping of the surface of the ball when scraping of the grease is reduced, The amount of grease that accumulates on the inner surface of the cage is reduced. Therefore, it is possible to prevent the grease from adhering to the inner ring seal groove Sm.

The consistency of grease will be described.
The relationship between grease consistency and grease leakage was also tested.
The test conditions are as shown in Table 3 below. In this test, the consistency was changed by increasing the proportion of base oil in the grease.

この試験結果により、グリースのちょう度が３８９以上でグリース漏れが確認された。したがって、グリースのちょう度の上限値は３８９が望ましい。 The test results are as shown in Table 4 and FIG.

From this test result, grease leakage was confirmed when the grease consistency was 389 or more. Accordingly, the upper limit value of the grease consistency is preferably 389.

  According to the rolling bearing described above, the energization of the outer ring 2 -the seal member 5 -the inner ring 1 is improved and the energization of the rolling portions of the inner and outer rings 1 and 2 is achieved by using the seal member 5 as a conductive material. It becomes possible to decrease. Further, since the retainer 4 is provided with the recessed portions 50 and 50A as grease leakage preventing portions for preventing the grease from flowing into the sliding contact portion Sb between the seal member 5 and the inner ring 1, an oil film is formed on the sliding contact portion Sb. May not be. Accordingly, it is possible to prevent brittle peeling by preventing the lowering of the conductivity between the inner and outer rings 1 and 2 and the seal member 5 and preventing the rolling surfaces 1a and 2a of the inner and outer rings 1 and 2 from being energized. Therefore, it is possible to prevent a decrease in bearing life due to brittle peeling.

  As another embodiment of the present invention, a cage 4A shown in FIGS. 12 and 13 is provided as a grease leakage prevention portion at a portion on the inner diameter side of the ball arrangement pitch circle PCD which is a ball arrangement pitch in the spherical shell plate portion 46A. A thin portion 46Aa is formed. The thin portion 46Aa is obtained by making the plate thickness t1 of the portion located on the outer diameter surface portion 1D on both sides of the rolling surface 1a of the inner ring 1 thinner than the plate thickness t0 of the flat plate portion 47a. When the seal groove Sm is provided, the outer diameter surface portion 1D is an outer diameter surface portion between the rolling surface 1a and the seal groove Sm. The spherical shell plate portion 46A reduces the plate thickness t1 of the portion located in the axial range W of the outer diameter surface portion 1D. In FIG. 12, the cross-sectional shape when the spherical shell-shaped plate portion 46A is not thinned is indicated by an imaginary line.

  The plate material t1 may be thinned by thinning the entire range from the portion corresponding to the ball arrangement pitch circle PCD to the inner diameter side in the radial direction of the cage, and between the ball arrangement pitch circle PCD and the cage inner edge. The range from the midway point to the inner diameter edge may be made thinner. In these cases, the plate thickness t1 may gradually become thinner toward the inner diameter side in the radial direction of the cage so that the inner diameter edge becomes the minimum plate thickness. You may do it. Further, while maintaining the shape of the inner surface of the pocket of the spherical shell-shaped plate portion 46A, the plate thickness may be reduced so that the shape of the outer surface changes, and the shape of the outer surface of the spherical shell-shaped plate portion 46A is maintained. The plate thickness may be reduced so that the shape of the pocket inner surface changes.

  In this cage 4A, a thin-walled portion 46Aa is formed in the inner diameter portion of the spherical shell-shaped plate portion 46A that constitutes the pocket 46 in this way, and this thin-walled portion 46Aa is in the axial direction with the outer-diameter surface portion 1D of the inner ring 1. The overlapping part is a part where the grease adhered to the surface of the ball is scraped off by the cage 4A, or the part where the scraped grease moves. If the plate thickness t1 of this portion 46Aa is thin, the amount of grease that can be deposited here decreases, so the frequency and amount that can reach the outer diameter surface portion 1D of the inner ring 1 decreases, and as a result, the grease flows to the outside of the bearing. Leakage can be prevented. That is, the grease easily moves to the outer diameter side of the cage 4A, and the amount of grease that can stay on the inner diameter side decreases.

However, reducing the overall plate thickness of the cage reduces the strength of the cage itself, and damage to the cage occurs when repeated stress is applied to the cage under misalignment or external vibration. It becomes difficult, such as becoming easy.
Therefore, in the inner diameter portion of the cage 4A, the thickness of only the range W that overlaps the outer diameter surface portion 2D of the inner ring 1 in the axial direction is thinned, and thereby there is no substantial decrease in strength of the cage 4A. And the holder | retainer 4A which can prevent grease leak is materialized.

  The cage 4B shown in FIG. 14 to FIG. 16 has a radial clearance δ between the outer diameter surface of the inner ring 1 and the inner diameter surface of the cage 4B as a grease leakage prevention portion when the ball diameter is Da. .09 Da or more. In addition, the maximum value allowed as the radial gap δ is set to 0.36 Da in consideration of the strength of the cage 4B, the shoulder diameters of the inner and outer rings 1 and 2, the amount of movement of the cage 4B, and the like. That is, the radial clearance δ in the rolling bearing is set to a value within a range of 0.09 Da to 0.36 Da (0.09 Da ≦ δ ≦ 0.36 Da).

In this rolling bearing, since the radial clearance δ between the outer diameter surface of the inner ring 1 and the inner diameter surface of the cage 4B is increased to 0.09 Da or more, a clearance for grease accumulated on the inner diameter side of the cage 4B is provided. It will be. Therefore, it is possible to prevent the grease from entering the seal groove Sm (FIG. 1) of the inner ring 1, thereby preventing the grease leakage. Accordingly, an oil film can be prevented from being formed on the sliding contact portion Sb (FIG. 2B) between the seal member 5 and the inner ring 1, thereby preventing a decrease in conductivity between the inner and outer rings 1, 2 and the seal member 5, It is possible to take measures against brittle peeling by preventing the rolling surfaces 1a and 2a of the inner and outer rings 1 and 2 from being energized.
The reason why the radial gap δ is desirably 0.36 Da or less is as follows.
That is, for the strength of the cage, the belt width (width B in the radial direction of the cage) needs to be 0.26 Da or more, and the inner and outer ring shoulder diameters (difference in radius between the raceway groove bottom and the shoulder) are 0.18 Da or more. Necessary, cage movement is MAX0.17 Da. Therefore, the clearance at the maximum movement amount is 0.36 Da.

  FIG. 17 is the same as the case of this embodiment except for the plurality of rolling bearings of this embodiment in which the radial clearance δ is 0.09 Da or more and the configuration other than the radial clearance δ. FIG. 5 is a plot of the test results of the grease leakage occurrence rate for a plurality of rolling bearings having a diameter of less than 0.09 Da. From this test result, it can be seen that in the rolling bearing of this embodiment in which the radial clearance δ is 0.09 Da or more, the grease leakage occurrence rate is remarkably reduced.

  In the rolling bearing shown in FIGS. 18 and 19, as shown in a plan view in FIG. 18, in the retainer 4 </ b> B, the inner peripheral surface of the circumferential portion with the pocket 46 is on the outer diameter side when viewed from the axial direction. It is set as the recessed part Ha of the polygonal shape to dent. Specifically, the inner peripheral surface has a pair of inclined surface portions Haa inclined to the outer diameter side with respect to the inner peripheral surface Hb of the circumferential portion between the pockets 46, and both ends have outer diameters of the pair of inclined surface portions Haa. It has a trapezoidal shape consisting of a constant-diameter surface portion Hab that is connected to the side end and has a constant inner diameter. Thereby, the radius Rp from the cage center of the inner diameter of the circumferential portion (recessed portion Ha) with the pocket 46 is larger than the radius Ri from the cage center of the inner diameter of the circumferential portion between the pockets 46. (Rp> Ri).

  In the case of this embodiment, when the diameter of the ball is Da, as shown in FIG. 19, the radial clearance δ1 between the outer diameter surface of the inner ring 1 and the recessed portion Ha of the cage 4B is 0.09 Da or more. It is said that. Further, the maximum value allowed as the radial gap δ1 is set to 0.36 Da in consideration of the strength of the cage 4B, the shoulder diameters of the inner and outer rings 1 and 2, the movement amount of the cage 4B, and the like. That is, the radial clearance δ1 in this rolling bearing is set to a value within the range of 0.09 Da to 0.36 Da (0.09 Da ≦ δ1 ≦ 0.36 Da). Also in this embodiment, the same result was obtained when the same grease leak rate test as in the previous embodiment was performed.

  FIG. 20 is a sectional view in which the rolling bearing BR1 according to the embodiment of the present invention is provided on the idler pulley. In the idler pulley 21, the rolling bearing BR1 is fitted on the outer periphery of the shaft 20, and the idler pulley 21 is rotatably supported by the rolling bearing BR1. This idler pulley bearing prevents brittle debonding by preventing leakage of grease, preventing a decrease in electrical conductivity between the inner and outer rings and the seal member, and preventing brittle debonding by preventing the rolling surfaces of the inner and outer rings from energizing. It is possible to prevent a decrease in bearing life due to.

FIG. 21 is a sectional view in which a rolling bearing according to an embodiment of the present invention is provided in an alternator 22 that is an electrical accessory. In this alternator 22, a shaft 23 is inserted into a rolling bearing BR1 used as a bearing for an alternator, and a pulley 24 is attached to an end portion of the protruding shaft 23. The pulley 24 is provided with an engagement groove 25 on which a transmission belt (not shown) is hung. This alternate bearing also prevents brittle delamination by taking measures against brittle delamination by preventing leakage of grease, preventing a decrease in electrical conductivity between the inner and outer rings and the seal member, and preventing energization of the rolling surfaces of the inner and outer rings. A decrease in bearing life can be prevented.
Although the deep groove ball bearing is applied as the rolling bearing of each of the embodiments, an angular ball bearing, a cylindrical roller bearing, or a tapered roller bearing can also be applied.

DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 1a, 2a ... Rolling surface 3 ... Rolling body 4 ... Cage 5 ... Seal member 5ba ... Constriction part 5c ... Lip part 46 ... Pocket 46A ... Spherical shell-shaped board part 47 ... Cage half body 47a ... Flat plate part 50, 50A ... Recessed part Lm ... Main lip Lb ... Labyrin slip Sm ... Seal groove

Claims (10)

In a rolling bearing in which a plurality of rolling elements are interposed between the rolling surfaces of the inner and outer rings, and a seal member is provided on the outer ring so that the lip portion is in sliding contact with the inner ring and closes the bearing space between the inner and outer rings.
The sealing member is a conductive material,
A rolling bearing comprising: a cage that holds the rolling element; and a grease leakage prevention portion that prevents the grease in the bearing space from flowing into a sliding contact portion between the seal member and an inner ring.   The rolling element according to claim 1, wherein the rolling element is a ball, and the grease leakage prevention portion has a concave spherical inner surface of the pocket that holds the ball of the cage, and the inner surface of the concave spherical pocket is arranged on the inner diameter side of the cage. A rolling bearing provided with a recess extending from the opening edge to the outer diameter side of the cage. 2. The rolling element according to claim 1, wherein the rolling element is a ball, and the cage is in a ring shape having pockets for holding the ball at a plurality of locations in the circumferential direction, and two annular cage halves are axially arranged. These retainer halves have a spherical shell-shaped plate portion whose inner periphery forms half of each pocket, and a flat plate portion that is a portion between adjacent pockets in the circumferential direction. Are alternately arranged in shape,
The grease leakage prevention portion has a plate thickness of a portion located at an outer diameter surface portion of at least a shoulder height on both sides of the rolling surface of the inner ring in a portion on the inner diameter side of the ball arrangement pitch circle in the spherical shell plate portion. A rolling bearing that is thinner than the plate thickness of the flat plate portion.   The rolling element according to claim 1, wherein the rolling element is a ball, and the grease leakage prevention portion has a radial clearance between the outer diameter surface of the inner ring and the inner diameter surface of the cage, equal to or greater than a value obtained by multiplying the diameter of the ball by 0.09. Rolling bearing.   The rolling bearing according to claim 4, wherein the radial clearance is not more than a value obtained by multiplying the diameter of the ball by 0.36. 6. The shoulder portion according to claim 1, wherein a seal groove is formed in a circumferential direction on the outer diameter surface of the inner ring, and the shoulder portion protrudes toward the outer diameter side between the seal groove and an end portion of the inner ring. And fixing the outer peripheral edge of the seal member to the inner surface of the outer ring facing the seal groove,
A main lip that comes into contact with and slides on the groove wall of the seal groove, and a labyrinth slip disposed radially outward of the shoulder portion are provided on the inner peripheral portion of the seal member,
A rolling bearing in which an inner peripheral surface facing the seal groove is provided on the main lip, and an inclined surface that increases in diameter toward the tip of the labyrin slip is provided on the inner peripheral side of the labyrin slip.   7. The rolling device according to claim 6, wherein a constriction portion connected to an outer diameter side from a base end portion of the main lip and the labyrin slip and having a constricted portion formed thinner than an axial thickness of the main lip and the labyrin slip is provided on the seal member. bearing.   The rolling bearing according to any one of claims 1 to 7, wherein the grease to be sealed in the bearing space has a consistency of less than 389.   A pulley bearing to which the rolling bearing according to any one of claims 1 to 8 is applied.   A bearing for automotive electrical equipment to which the rolling bearing according to any one of claims 1 to 8 is applied.

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