JP2009228683A - Retainer for ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retainer for ball bearings that can prevent grease sealed inside the bearings from leaking outside and that can achieve the extension of grease lubricating life, high-speed rotation performance peculiar to the retainer of a steel sheet, and the obtainment of bearing resting spaces larger than a resin retainer. <P>SOLUTION: The steel retainer 5 used for ball bearings is formed in a ring shape having pockets 5a for retaining balls 4 at a plurality of circumferential positions. The radius from the center of the retainer of the inside diameter of the circumferential part having the pockets 5a is made larger than the radius from the center of the retainer of the inside diameter of the circumferential part between the pockets 5a. Furthermore, films 13 made of either one of resin, a soft metal and a solid lubrication material are formed at least on the ball guide surface of the pockets 5a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cage for a ball bearing with a sealing plate used in a rotation support portion of various rotary machine devices, and in particular, prevents grease enclosed inside the ball bearing for lubrication from leaking outside, and The present invention relates to a technology for extending the life of grease.

Ball bearings used in various types of rotating machinery, especially automobile auxiliary machines, are required to have high temperature resistance, high speed resistance, muddy water resistance, dust resistance, grease leakage resistance, long life and low torque. As a countermeasure, contact seals are provided at both ends of the space between the bearing inner and outer rings.
In a sealed ball bearing with such a structure, if the bearing temperature rises when grease is present in the seal lip portion of the contact seal, the pressure inside the bearing rises due to the expansion of air inside the bearing. A phenomenon (hereinafter referred to as “breathing”) occurs in which the seal lip portion opens due to the pressure difference and grease or air in the bearing leaks to the outside of the bearing (hereinafter referred to as breathing).

As a countermeasure for preventing this breathing phenomenon, there has been proposed one in which a notch for ventilation is provided in a part of the seal lip portion (Patent Document 1). However, when grease adheres to the notch, grease leakage similar to that of the ball bearing described above occurs (Patent Document 2).
For example, in a ball bearing for inner ring rotation, the pressure for sealing lip is pressed against the seal groove on the outer diameter surface of the inner ring against which the seal lip portion of the contact seal is pressed (hereinafter referred to as an urging force). It is conceivable to take measures for breathing as described above. However, this only causes an increase in torque, and cannot prevent grease leakage at a large temperature rise that causes an internal pressure higher than the tension force. Further, when the bearing temperature is lowered, the internal pressure is lowered due to the contraction of the air inside the bearing, so that an adsorption phenomenon of the seal lip tip occurs, which causes a further increase in torque (for example, Patent Document 3). .
For these reasons, even if the contact seals having various structures described above are used, it is difficult to prevent grease leakage if grease adheres to the inner ring seal groove.

  Thus, a ball bearing cage (hereinafter referred to as an improved iron plate cage) in which the shape of the iron plate corrugated cage is changed to prevent grease leakage has been proposed (Patent Document 4). In this cage, the radius from the cage center of the inner diameter of the circumferential portion with the pocket is made larger than the radius from the cage center of the inner diameter of the circumferential portion between the pockets, and the portion with the larger inner diameter The excess grease attached to the ball is scraped to prevent the grease from adhering to the shoulder of the inner ring.

However, since the guide surface of the ball (steel ball) in the pocket is iron in the standard iron plate corrugated cage and the above-described improved iron plate cage, iron wear powder is generated by sliding of the ball on the guide surface, The grease will deteriorate and the bearing will have a short life.
Even if an attempt is made to use a general crown-shaped resin cage (PA66 + GF25%) instead of the iron plate corrugated cage, it is difficult to take measures against grease leakage. In addition, since the cage is deformed to the outer ring side by the centrifugal force generated at the time of high speed rotation and contacts the inner diameter of the outer ring, there is a problem in high speed rotation performance. In order to suppress the deformation caused by the centrifugal force, a high-strength resin (PEEK material or the like) may be used as a material for the cage, but this makes the cage expensive.

The structure of the improved iron plate cage disclosed in Patent Literature 4 in which the shape of the iron plate corrugated cage is changed and improved with respect to the two-folded resin cage (Patent Literatures 5 and 6) advantageous in terms of deformation under high-speed rotation It is also possible to adopt. However, even in this case, since the thickness of the resin cage cannot be reduced to the same level as that of the iron plate, it is still difficult to prevent grease leakage. In this case, even if the plate thickness is increased, the volume of the cage increases and the spatial volume in the bearing decreases, so it is necessary to reduce the amount of grease charged compared to the iron plate corrugated cage. It leads to decline.
JP 2000-257640 A JP 2005-308117 A Japanese Patent Laid-Open No. 2005-066944 JP 2007-271078 A JP 2006-258174 A JP 2007-040383 A

As described above, according to the improved iron plate cage disclosed in Patent Document 4, it is possible to prevent grease leakage, but iron wear powder is generated, and the bearing life is shortened. Further, in the crown-shaped resin cage, the grease lubrication life itself of the bearing is excellent, but it is difficult to take measures against grease leakage. In addition, the high-speed rotation performance is inferior. In addition, it is difficult to take countermeasures against grease leakage even in a split resin cage excellent in high-speed rotation performance due to restrictions on strength of the cage alone. In addition, a reduction in the space volume in the bearing leads to a reduction in grease lubrication life.
As described above, each of the above-described configurations cannot provide a cage that is effective in preventing grease leakage and that has a grease lubrication life similar to that of a resin cage.

  The object of the present invention is to prevent the grease enclosed in the bearing from leaking to the outside, extend the grease lubrication life, high high-speed rotation performance peculiar to the iron plate cage, and larger bearing static space than the resin cage It is an object of the present invention to provide a cage for a ball bearing that can achieve the above.

The ball bearing cage of the present invention is a ring-shaped iron cage used in ball bearings and provided with pockets for holding balls at a plurality of locations in the circumferential direction. The radius from the cage center is larger than the radius from the cage center of the inner diameter of the circumferential portion between the pockets, and at least the guide surface of the ball in the pocket is made of resin, soft metal, solid lubricant A film made of any of the above is formed. The inner diameter surface of the circumferential portion with the pocket may be a curved surface shape that is a concave curve when viewed from the axial direction, or a polygonal shape having a plurality of corners. The polygonal shape can be a part of a regular polygon, for example.
The inner ring shoulder or inner ring seal is made by making the radius of the inner diameter of the circumferential portion of the cage pocket with the inner radius of the cage larger than the radius of the inner diameter of the circumferential portion between the pockets from the cage center. Grease is difficult to adhere to the groove. This appears particularly when the outer ring rotates. Thereby, leakage of grease can be prevented regardless of whether the seal is a contact type or a non-contact type. Further, since it is not necessary to increase the tightening force of the seal lip, the torque does not increase. Each of the above-described actions can be obtained in any case where the inner diameter surface of the circumferential portion having the pocket is a curved surface having a concave curve when viewed from the axial direction, or a polygonal shape having a plurality of corners.
Further, by forming a film made of any of resin, soft metal, and solid lubricant on at least the ball guide surface in the pocket, the ball, which is a steel ball, does not directly contact the iron ball guide surface. In other words, since the ball, which is a steel ball, slides on the film formed on the ball guide surface in the pocket, iron wear powder does not occur with the sliding, and grease deterioration due to the wear powder occurs. The grease lubrication life can be extended.
Further, since this cage is an improvement of the iron plate corrugated cage, it is possible to secure a high-speed rotation performance peculiar to the iron plate corrugated cage and a bearing stationary space larger than the resin cage. Since the amount of grease filled in the bearing is generally specified in proportion to the bearing static space, this cage can expect an increase in the amount of grease filled due to an increase in the bearing static space, and the bearing life Extension is possible.

In this invention, the circumference with pockets is inclined by inclining the inner circumferential surface of the circumferential part with each pocket so that the circumferential center of each circumferential part with pockets has a large diameter. The radius of the inner diameter of the directional portion from the cage center may be larger than the radius of the inner diameter of the circumferential portion between the pockets from the cage center.
With this configuration, the radius from the cage center of the inner diameter of the circumferential portion with the pocket is made smaller than the radius from the cage center of the inner diameter of the circumferential portion between the pockets while avoiding a decrease in the overall strength. You can make it bigger.

In the present invention, the annular member includes two annular members that are axially overlapped with each other, and each annular member is arranged at a predetermined interval in the circumferential direction, and each includes a plurality of hemispherical pocket wall portions constituting the inner wall surface of the pocket. It is made up of a flat plate-like connecting plate portion that connects the adjacent pocket wall portions, and both the annular members can be connected to each other at the connecting plate portions.
If the cage is configured as described above, the cage can be easily processed.

  In the present invention, the film may be made of a synthetic resin.

  In the present invention, the film may be made of a soft metal, and the soft metal may be any one of copper, silver, gold, and indium.

  In the present invention, the film is made of a solid lubricant, and the main component of the solid lubricant may be any of molybdenum disulfide, tungsten disulfide, and graphite.

  The ball bearing cage of the present invention is a ring-shaped iron cage used in ball bearings and provided with pockets for holding balls at a plurality of locations in the circumferential direction. The radius from the cage center is larger than the radius from the cage center of the inner diameter of the circumferential portion between the pockets, and at least the guide surface of the ball in the pocket is made of resin, soft metal, solid lubricant As a film made of any of the above is formed, the grease enclosed in the bearing can be prevented from leaking to the outside, and the grease lubrication life can be extended, the high-speed rotation performance unique to the iron plate cage, and the resin cage A large bearing static space can be secured.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a ball bearing incorporating the cage of the present invention, and FIGS. 2 and 3 show the cage. The ball bearing 1 is a deep groove ball bearing, and includes an inner ring 2, an outer ring 3, a plurality of balls 4 interposed between the inner and outer rings 2 and 3, and a cage 5 that holds each ball 4. Yes. Openings at both ends in the axial direction of the annular space formed between the outer periphery of the inner ring 2 and the inner periphery of the outer ring 3 are attached to the outer ring seal groove 3a formed on the inner peripheral surface of the outer ring 3, and the inner end is the inner ring. 2 is closed by a sealing plate 6 as a contact seal which is fitted in an inner ring seal groove 2a formed on the outer peripheral surface 2 and slidably contacts the inner ring 2. And the grease for lubrication is enclosed with the closed annular space.

  The cage 5 is a ring-shaped member, and the same number of window-like pockets 5a that accommodate and hold the balls 4 as the balls 4 are formed at equal intervals in the circumferential direction. The inner circumferential surface 5b of the circumferential portion with the pocket 5a is inclined so as to be recessed toward the outer diameter side, and the radius Rp from the cage center of the inner diameter of the circumferential portion with the pocket 5a is the pocket 5a. The inner diameter of the circumferential portion between them is larger than the radius Ri from the cage center (Rp> Ri). In this embodiment, the inner peripheral surface 5b is a curved surface that is a concave curve when viewed from the axial direction, specifically, an arcuate surface.

  The cage 5 is composed of two annular members 11 manufactured by punching and forming an iron plate with a press. Each annular member 11 is arranged in the circumferential direction at equal intervals, and each of the hemispherical pocket wall portions 11a constituting the inner wall surface of the pocket 5a and a flat plate-like coupling plate that connects the adjacent pocket wall portions 11a to each other. The portions 11b are alternately formed. A rivet hole 11c is formed in the coupling plate portion 11b of the annular member 11 made of iron plate. The two annular members 11 are joined by overlapping the respective coupling plate portions 11b with each other, inserting the rivet 12 into the rivet hole 11c, and crimping both ends of the rivet 12. In this way, if the two annular members 11 are coupled to each other to form one cage 5, the radii from the center of the cage having the inner diameter as described above are different in each part, and the holding is performed. The processing of the vessel 5 is easy.

  At least the guide surface of the ball 4 in the pocket 5a of the cage 5, that is, the inner peripheral surface of each hemispherical pocket wall portion 11a of the two annular members 11 made of iron plate is made of resin, soft metal, or solid lubricant. A film 13 made of any of these is formed. The coating 13 prevents the balls 4 made of steel balls from coming into direct contact with the ball guide surfaces of the cage pockets 5a made of iron.

The material of the film 13 may be a material mainly composed of a mixture of the resin, soft metal, and solid lubricant. The resin used as the material of the film 13 may be a synthetic resin. The synthetic resin in this case is not particularly limited as long as it is a material having oil resistance, strong film strength when formed into the film 13, and excellent wear resistance. Examples of such synthetic resins include thermosetting resins such as epoxy resins, phenol resins, polycarbodiimide resins, furan resins, bismaleimide triazine resins, unsaturated polyester resins, silicone resins, polyamino bismaleimide resins, aromatic polyimide resins, etc. Resin, polyolefin resin, polyacetal resin, polyamide resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin, polyether sulfone resin, polyetherimide resin, thermoplastic polyimide resin, aromatic polyamideimide resin, polybenzimidazole resin, poly Examples thereof include thermoplastic resins such as ether ketone resins, polyether nitrile resins, fluorine resins, and aromatic polyester resins.
Among these, preferred examples of the synthetic resin for the coating 13 include aromatic polyamideimide resin, aromatic polyimide resin, epoxy resin, phenol resin, polyphenylene sulfide resin, and the like. These synthetic resins can be blended with various fillers in the form of fibers and particles as necessary.

  When a soft metal is used as the material of the film 13, the soft metal is preferably any one of copper, silver, gold, and indium. Further, when a solid lubricant is used as the material of the film 13, the main component of the solid lubricant is preferably molybdenum disulfide, tungsten disulfide, or graphite.

  In the cage 5 of this embodiment, since the inner peripheral surface 5b of the circumferential portion having the pocket 5a is recessed to the outer diameter side, there is a concern that the overall strength may be lowered. However, most of the damage of the conventional standard-shaped cage 25 (Rp = Ri) as shown in FIG. 8 is a connecting portion from the circumferential portion between the pockets 5a to the circumferential portion where the pockets 5a are located. It is empirically known to occur at 7. Since the cage 5 of this embodiment does not change the shape of this portion, it can be said that the overall strength does not decrease.

  In order to investigate the state of grease during operation of the ball bearing 1, tests were conducted under the conditions shown in Table 1. The state of adhesion of grease to each part of the bearing after the operation was stopped was as shown in FIG. For comparison, a test was also performed under the same conditions for a bearing incorporating the conventional cage 25 shown in FIG. The state of adhesion of grease to each part of the bearing after the operation was stopped was as shown in FIG.

  According to this test, the grease G adheres to the inner ring seal groove 2a in the case of the bearing incorporating the conventional cage 25, but the grease G does not adhere to the inner ring seal groove 2a in the bearing incorporating the cage 5 of the present invention. I found out. For this reason, it is inferred that in the ball bearing 1 provided with the sealing plate 6, leakage of the grease G from the portion of the inner ring seal groove 2a due to breathing can be prevented.

  Next, a grease leakage frequency confirmation test was performed using a bearing assembled with a contact seal (LU seal manufactured by NTN Corporation). For the test conditions, only the operation time was changed to 15 minutes with respect to the conditions in Table 1. When it was confirmed by visual inspection that grease of an amount of about 30 to 100 mg had jumped out of the bearing, grease leakage was assumed. The test results are shown in Table 2.

  Nine out of 10 grease leaks occurred in the bearing incorporating the conventional cage 25, but none of the bearings incorporating the cage 5 of the present invention produced any grease leakage. This proved that the reasoning was correct.

  Further, the cage 5 of this embodiment has at least the guide surface of the ball 5 in the pocket 5a, that is, the inner peripheral surface of the pocket wall portion 11a of the annular member 11 made of iron plate, of resin, soft metal, solid lubricant. Since the film 13 made of any one of them is formed, the ball 4 which is a steel ball does not directly contact the iron ball guide surface. That is, since the ball 4 which is a steel ball slides on the film 13 formed on the ball guide surface in the pocket 5a, iron wear powder is not generated along with the slide, and is caused by the wear powder. There is no grease deterioration and the grease lubrication life can be extended. Thereby, the lifetime of the ball bearing 1 incorporating this cage 5 can be extended.

  In order to investigate the life extension effect of the ball bearing 1, tests were conducted under the operating conditions shown in Table 3.

  In this test, a ball bearing incorporating a crown-shaped resin cage is simulated as a ball bearing 1 incorporating a coated cage 5 of this embodiment, and a ball bearing incorporating an iron plate corrugated cage without a coating is used. The bearing life was compared. That is, in the cage 5 of this embodiment, the crown-shaped resin cage is used as the material of the film 13 made of resin. The test results are shown in Table 4.

  From Table 4, the ball bearing incorporating the iron plate corrugated cage with no coating has a bearing life of about 30 compared to the ball bearing incorporating the crown-shaped resin cage mimicking the cage with coating 5 of this embodiment. % Turned out to be short. Thereby, the bearing life can be extended by incorporating the cage 5 of this embodiment in which the film 13 made of any of resin, soft metal, and solid lubricant is formed on the ball guide surface of the pocket 5a. Is inferred.

  In addition, since the cage 5 is an improvement of the iron plate corrugated cage, it is possible to secure a high-speed rotation performance unique to the iron plate corrugated cage and a bearing static space larger than the resin cage. Since the amount of grease filled in the bearing is generally defined in proportion to the bearing static space, this cage 5 is expected to increase the amount of grease filled due to the increase in the bearing static space. Therefore, the bearing life can be extended.

  From these facts, according to the cage 5 of the configuration of this embodiment, not only can grease leakage be suppressed, but also a high rotational performance unique to the iron plate corrugated cage and a bearing stationary space larger than the resin cage can be secured, Grease lubrication life can be extended.

  In the said embodiment, although it was set as the structure which couple | bonds the two annular members 11 and makes it the one holder | retainer 5, it is good not only as this structure but as a machined holder which cuts out from steel materials to a defined shape.

  FIG. 7 shows a different embodiment. In the retainer 35, the shape of the inner peripheral surface 5b of the circumferential portion having the pocket 5a is a polygonal shape when viewed from the axial direction. Specifically, the inner peripheral surface 5b includes a pair of inclined surface portions 5ba that are inclined toward the outer diameter side with respect to the inner peripheral surface 5c in the circumferential portion between the pockets 5a, and both ends of the inner peripheral surface 5b are outside the pair of inclined surface portions 5ba. It has a trapezoidal shape composed of a constant-diameter surface portion 5bb connected to the radial end and having a constant inner diameter. Similarly to the cages 5 and 15 of the above-described embodiment, the cage 35 is also inclined so that the inner circumferential surface 5b of the circumferential portion with the pocket 5a is recessed in the outer diameter side. The radius Rp from the cage center of the inner diameter of the circumferential portion with 5a is larger than the radius Ri from the cage center of the inner diameter of the circumferential portion between the pockets 5a (Rp> Ri).

  In this way, the cage 35 having a polygonal shape when viewed from the axial direction in the shape of the inner peripheral surface 5b of the circumferential portion with the pocket 5a is also reduced in overall strength, like the cages 5 and 15 of the above embodiment. 1 and the leakage of grease from the inner ring seal groove 2a of the bearing 1 can be prevented when incorporated in the bearing as shown in FIG.

  In addition, when making the internal peripheral surface 5b of the circumferential direction part with the pocket 5a into the polygonal shape which has a some corner | angular part, the number of the corner | angular part is not specifically limited. Further, the shape may be asymmetric with respect to a straight line in the radial direction. Furthermore, the inner peripheral surface 5b of the circumferential direction part with the pocket 5a may be a combination of a flat surface and a curved surface.

It is sectional drawing of the ball bearing incorporating the holder concerning one Embodiment of this invention. It is a front view of the retainer. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a figure which shows the test result performed with respect to the ball bearing incorporating the said holder | retainer. It is a front view of a different holder. It is a perspective view which shows the principal part of the annular member of the holder. It is a front view of the holder | retainer concerning other embodiment of this invention. It is a front view of the conventional cage | basket. It is a figure which shows the test result performed with respect to the ball bearing incorporating the said holder | retainer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ball bearing 2 ... Inner ring 3 ... Outer ring 4 ... Ball | bowl 5, 15, 25.35 ... Cage 5a ... Pocket 5b ... Inner peripheral surface 6 ... Sealing plate 11 ... Ring member 11a ... Pocket wall part 11b ... Coupling Plate part 13 ... Coating Ri ... Radius from the cage center of the inner diameter of the circumferential part between the pockets Rp ... Radius from the cage center of the inner diameter of the circumferential part with the pocket

Claims (8)

  In a ring-shaped iron cage that is used for ball bearings and has pockets for holding balls at multiple locations in the circumferential direction, the radius from the cage center of the inner diameter of the circumferential portion with the pocket is determined between the pockets. The inner diameter of the circumferential portion of the ball is larger than the radius from the center of the cage, and a coating made of any of resin, soft metal, and solid lubricant is formed on at least the ball guide surface in the pocket. Ball bearing cage characterized by   The ball bearing retainer according to claim 1, wherein the inner circumferential surface of the circumferential portion having the pocket is a curved surface having a concave curve when viewed in the axial direction.   2. The ball bearing retainer according to claim 1, wherein the inner circumferential surface of the circumferential portion having the pocket is a polygonal shape having a plurality of corners when viewed from the axial direction.   The inner circumferential surface of the circumferential portion with each pocket according to any one of claims 1 to 3, wherein a circumferential central portion of each circumferential portion with the pocket has a large diameter. A ball bearing retainer in which the radius from the cage center of the inner diameter of the circumferential portion between the pockets is larger than the radius from the cage center of the inner diameter of the circumferential portion between the pockets by inclining.   5. The structure according to claim 1, comprising two annular members that are axially overlapped with each other, and each annular member is arranged at a predetermined interval in the circumferential direction, and each constitutes an inner wall surface of the pocket. A plurality of hemispherical pocket wall portions and a flat plate-like connecting plate portion connecting adjacent pocket wall portions, and both annular members are connected to each other at the connecting plate portions. Ball bearing cage.   The ball bearing retainer according to any one of claims 1 to 5, wherein the film is made of a synthetic resin.   6. The ball bearing retainer according to claim 1, wherein the coating is made of a soft metal, and the soft metal is any one of copper, silver, gold, and indium. 6. The ball bearing according to claim 1, wherein the film is made of a solid lubricant, and the main component of the solid lubricant is any one of molybdenum disulfide, tungsten disulfide, and graphite. Cage.

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