JP5687012B2 - Sealed rolling bearing - Google Patents

Description

  The present invention relates to a hermetic rolling bearing in which a bearing space between an inner ring and an outer ring is sealed with a seal member.

  In general, a rolling bearing is required to have a low torque. Various types with low torque specifications have been proposed (Patent Document 1 and Patent Document 2). In Patent Document 1 and Patent Document 2, a cage is formed by fastening a pair of press forming plates with fastening means, and a pocket recess is provided on the inner surface of each press forming plate. A pocket into which a ball as a rolling element is fitted is formed in the recess. A recess or the like as a lubricant (grease) reservoir is provided on the inner surface of the pocket recess.

JP 2003-13962 A JP 9-317775 A

  In Patent Document 1 and Patent Document 2, the sliding contact area between the ball and the pocket of the cage can be reduced, and the torque can be reduced. However, in a sealed type rolling bearing in which the bearing space between the inner ring and the outer ring is sealed with a seal member, the seal lip of the seal member slides to the other side. It is not possible to achieve much lower torque simply by providing it. In addition, as a factor that cannot achieve low torque, there is a stirring resistance of grease. In the Patent Document 1 and Patent Document 2, the stirring resistance cannot be reduced.

  Therefore, in view of such circumstances, the present invention intends to provide a sealed type rolling bearing capable of achieving a significant reduction in torque.

Tightly sealing type rolling bearing of the present invention, an inner ring, an outer ring, comprising a rolling element interposed between the inner and outer rings, and a cage holding the rolling elements, both end openings of the bearing axial direction Sealed rolling bearings, each sealed with a seal member and filled with grease in the bearing space, with a grease retaining groove around the outer diameter surface of the cage for reducing the amount of grease flow to the rolling surface. The grease reservoir groove is provided along the direction and is located on the bearing axial pocket opening side of the tangent line connecting the pockets adjacent to each other in the circumferential direction and connecting the bearing axial pocket bottom of the cage.

According to tightly seal type rolling bearing of the present invention, by providing the grease reservoir groove on the outer diameter surface of the cage, the flow of the grease into the rolling surface of the rolling elements grease accumulated in the groove (ball) Can be reduced. Thereby, the stirring resistance of grease can be reduced.

  It is preferable that the amount of grease filled be 65% or more and 80% or less of the static space volume. Here, the static space volume is a volume of a space through which the rolling elements and the cage do not pass during bearing rotation in the space volume of the inner ring, the outer ring, and the seal member.

  When the amount of grease filled is less than 65% of the static space volume, the reachability to the seal groove into which the seal lip of the seal member of the oil in the filled grease is fitted is lowered. Further, if the lubricating grease is filled in excess of 80% of the static space volume, the lubricating grease may leak from the rolling bearing. For this reason, by setting the grease filling amount to 65% or more and 80% or less of the static space volume, the oil content of the filled grease can sufficiently reach the seal groove, and the sliding resistance of the seal lip of the seal member can be reduced. Moreover, the lubricating effect is sufficiently exhibited.

  The cage is formed by cutting and may be formed by injection molding. The cage material may be a polyamide resin, a polyether ether ketone resin, a polyphenylene sulfide resin, or a phenol resin. The polyamide resin is a polymer compound having an amide bond (the same bond as a protein) formed by a reaction between an acid and an amine. The polyether ether ketone resin is a kind of aromatic polyether ketone resin, and is a synthetic resin belonging to a crystalline thermoplastic resin. Polyetherketone (PEK) has a basic linear structure in which ether bonds and ketone bonds are alternately arranged, and PEEK (polyetheretherketone) has bonds arranged in the order of ether, ether, and ketone. It is. Polyphenylene sulfide resin (PPS) is a thermoplastic crystalline plastic, and is a high-performance resin classified into the category of high heat-resistant resins called super engineering plastics. Phenolic resin is one of thermosetting resins made from phenol and formaldehyde.

  The seal rubber material of the seal member may be nitrile rubber, acrylic rubber, or fluororubber. The sealed rolling bearing can be used for a clutch release, a pulley, or an electrical accessory.

Tightly sealing type rolling bearing of the present invention, since it is possible to reduce the stirring resistance of the grease, can achieve low torque.

  By making the amount of grease filled 65% to 80% of the static space volume, the sliding resistance of the seal lip of the seal member can be relaxed, and coupled with the reduction of grease stirring resistance, the torque can be greatly reduced. Can be achieved. Moreover, the lubricating effect is sufficiently exerted, and the service life (life) can be extended.

  The cage is formed by cutting, may be formed by injection molding, and can form various types of cages adapted to the site to be used. In addition, as a material for the cage, various resin materials such as polyamide resin can be used, and the degree of freedom of design is widened.

  The sealed rolling bearing can be used for a clutch release, a pulley, or an electrical accessory. Clutch release bearings, pulley bearings, and electrical accessory bearings are strongly required to prevent grease leakage, reduce torque, and have high dust resistance. Therefore, a bearing like the present invention is optimal.

It is a perspective view of the holder | retainer of the sealing type rolling bearing which shows embodiment of this invention. It is principal part sectional drawing of the said sealing type rolling bearing. It is a perspective view of the holder | retainer of the sealing type rolling bearing which shows other embodiment of this invention. It is principal part sectional drawing of the bearing for clutch release. It is principal part sectional drawing of an idler pulley. It is sectional drawing of an alternator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a cross-sectional view of the main part of the sealed rolling bearing 100. The sealed rolling bearing 100 is used for an electrical accessory such as an idler pulley or an alternator, for example. The sealed rolling bearing is interposed between an inner ring 1 having an inner rolling surface 1a formed on the outer peripheral surface, an outer ring 2 having an outer rolling surface 2a formed on the inner peripheral surface, and the rolling surfaces 1a and 2a. A ball 3 as a rolling element and a holder 4 for holding the ball 3. In addition, both end openings in the axial direction of the annular space between the inner ring 1 and the outer ring 2 are sealed with a seal member 5.

  The seal member 5 includes an annular cored bar 7 and a rubber-like member 8 that is integrally fixed to the cored bar 7. The outer peripheral part of the seal member 5 is fitted in a seal mounting groove 9 formed on the inner peripheral surface of the outer ring 2. Fixed to state. The inner ring 1 is formed with a seal groove 10 formed of a circumferential groove at a position corresponding to the inner peripheral portion of each contact seal 5, and a seal lip 11 formed at the inner peripheral side end of the seal member 5 is a seal groove of the inner ring 1. 10 is in sliding contact.

  As shown in FIG. 1, the retainer 4 includes an annular retainer body 15 in which recesses 17 disposed at a predetermined pitch along the circumferential direction are formed on one axial end surface 16, and the retainer body 15. And a claw portion 18 protruding from the opening end facing the circumferential direction of the concave portion 17. And the pocket 19 in which the said ball | bowl 3 is hold | maintained is comprised by the recessed part 17 and a pair of nail | claw parts 18 and 18 which protrude from this opening end.

  As shown in FIG. 2, the cage main body 15 is provided with a thinning groove 21 on the other axial end surface 20. The meat thinning groove 21 equalizes the cooling rate at the time of molding the cage to prevent the occurrence of voids (cavities formed inside the molded product), sink marks (shrinkage distortion appearing on the outer surface of the molded product), warpage, and the like. It is provided for such purposes.

  The cage 4 may be made of metal such as carbon steel, spring steel, or stainless steel, or may be made of resin such as polyamide resin, polyether ether ketone resin, polyphenylene sulfide resin, or phenol resin. The metal cage 4 is molded by cutting or the like, and the resin cage 4 is molded by injection molding or the like. The polyamide resin is a polymer compound having an amide bond (the same bond as a protein) formed by a reaction between an acid and an amine. The polyether ether ketone resin is a kind of aromatic polyether ketone resin, and is a synthetic resin belonging to a crystalline thermoplastic resin. Polyetherketone (PEK) has a basic linear structure in which ether bonds and ketone bonds are alternately arranged, and PEEK (polyetheretherketone) has bonds in the order of ether, ether, and ketone. It is. Polyphenylene sulfide resin (PPS) is a thermoplastic crystalline plastic, and is a high-performance resin classified into the category of high heat-resistant resin called super engineering plastic. Phenolic resin is one of thermosetting resins made from phenol and formaldehyde.

  Grease is a semi-solid lubricant composed of base oil, thickener and additives. Examples of the base oil constituting the lubricating grease include mineral oils such as paraffinic mineral oil and naphthenic mineral oil, hydrocarbon synthetic oils such as polybutene, poly-α-olefin, alkylbenzene, alkylnaphthalene, and alicyclic compounds, or Natural oils and fats, polyol ester oils, phosphate esters, diester oils, polyglycol oils, silicone oils, polyphenyl ether oils, alkyl diphenyl ether oils, non-hydrocarbon synthetic oils such as fluorinated oils, etc. Any oil that is used can be used without particular limitation.

  Examples of the thickener include metal soap-based thickeners such as aluminum soap, lithium soap, sodium soap, composite lithium soap, composite calcium soap, composite aluminum soap, and urea compounds such as diurea compounds and polyurea compounds. . These thickeners may be used alone or in combination of two or more.

  Known additives for lubricating greases include, for example, extreme pressure agents, amine-based and phenol-based antioxidants, metal deactivators such as benzotriazole, viscosity index improvers such as polymethacrylate and polystyrene, and molybdenum disulfide. And solid lubricants such as graphite. These can be added alone or in combination of two or more.

  As shown in FIG. 1, the retainer 4 is provided with a grease retaining groove 26 on the outer diameter surface 25 thereof. The grease reservoir groove 26 has a substantially V-shaped cross section. By providing the grease pool groove 26, grease can be collected in the grease pool groove 26, and the grease flow to the rolling surfaces 1a and 2a can be reduced. For this reason, the stirring resistance of grease can be reduced.

  By the way, the size of the grease reservoir groove 26 can be variously changed according to the size of the cage itself, the material used, and the like. In this case, if it is too large, it will be inferior in strength, and if it is too small, the amount of grease will be small, and the grease flow to the rolling surfaces 1a, 2a cannot be reduced. For this reason, it can change variously in the range which is not inferior in strength and can reduce grease flow.

  It is preferable that the amount of grease filled be 65% or more and 80% or less of the static space volume. Here, the static space volume is the volume of the space through which the rolling elements 3 and the cage 4 do not pass during bearing rotation in the space volume of the inner ring 1, the outer ring 2, and the seal members 5 and 5.

  When the amount of grease filled is less than 65% of the static space volume, the reachability to the seal groove 10 into which the seal lip 11 of the seal member 5 of the oil in the filled grease fits is lowered. Further, if the lubricating grease is filled in excess of 80% of the static space volume, the lubricating grease may leak from the rolling bearing. For this reason, by setting the grease filling amount to 65% or more and 80% or less of the static space volume, the oil content of the filling grease reaches the seal groove 10 sufficiently, and the sliding resistance of the seal lip 11 of the seal member 5 is reduced. In addition, the lubricating effect is sufficiently exhibited.

  In the sealed type rolling bearing of the present invention, the grease retaining groove 26 is provided on the outer diameter surface 25 of the cage 4, whereby the flow of grease to the rolling surface of the rolling element (ball) can be reduced. For this reason, since the stirring resistance of grease can be reduced, low torque can be achieved.

  Moreover, the sliding resistance of the seal lip 11 of the seal member 5 can be relaxed by setting the amount of grease filled to 65% or more and 80% or less of the static space volume. Low torque can be achieved. Moreover, the lubricating effect is sufficiently exerted, and the service life (life) can be extended.

  By the way, as shown in FIG. 3, the cage 4 may be one in which chamfered portions 30 and 31 for reducing scraping resistance are formed at the inner diameter side and outer diameter side edge portions of the pocket 19. As the chamfering, by forming the chamfered portions 30 and 31 in this way, it is possible to reduce the scraping resistance by the edge portions on the inner diameter side and the outer diameter side of the pocket 19. In addition, the grease stirring resistance can be reduced.

  By the way, it is necessary to set the size of the chamfered portions 30 and 31 within a range in which the scraping resistance can be reduced and the strength is not inferior and the ball cannot be stably held. Also, the edge portions of the chamfered portions 30 and 31 are preferably rounded in order to reduce the scraping resistance.

  Therefore, even when the cage 4 as shown in FIG. 3 is used, a reduction in torque can be achieved as in the cage 4 shown in FIG. When a sealed rolling bearing is configured using the cage 4 as shown in FIG. 3, the amount of grease filled is set to 65% to 80% of the static space volume. For this reason, the sliding resistance of the sealing lip of the sealing member can be relaxed, and a significant reduction in torque can be achieved in combination with a reduction in the stirring resistance of the grease. Moreover, the lubricating effect is sufficiently exerted, and the service life (life) can be extended.

  The cage 4 as shown in FIG. 3 may be made of metal or resin. That is, the same material as the cage 4 shown in FIG. 1 can be selected.

  Next, FIG. 4 shows a sealed rolling bearing 200 used in a clutch release bearing device incorporated in a clutch device of a vehicle such as an automobile as a modification of the sealed rolling bearing 100 according to the present invention. The clutch release bearing device is used to transmit or cut power from the engine to the transmission by operating a clutch pedal in a manual vehicle (MT vehicle) or the like, and is interposed between the engine and the transmission. .

  In FIG. 4, a sealed rolling bearing 200 used in a push-type clutch release bearing device is interposed between an outer ring 44 that is a rotating ring, an inner ring 45 that is a stationary ring, and an outer ring 44 and an inner ring 45. The main part is composed of the ball 46 and the retainer 4 of FIG. The engine-side end of the outer ring 44 extends radially inward to form a flange 49, and the front-side end of the inner ring 45 extends radially inward to form a flange 50. The flange portion 49 of the outer ring 44 is always in contact with the diaphragm spring 60 by a preload spring (not shown) built in a cover member (not shown) attached to the rear end of the inner ring 45. is there.

  Annular seal members 47 and 48 are provided at both axial ends between the outer ring 44 and the inner ring 45, whereby a sealed space is formed between the outer ring 44 and the inner ring 45. The seal members 47 and 48 are formed by vulcanizing and welding rubber members 58 and 59 to the core bars 56 and 57. In this embodiment, the example using the cage of FIG. 1 is shown, but the cage of FIG. 3 may be used.

  Next, FIG. 5 shows a cross-sectional view in which a sealed rolling bearing 100 according to the present invention is provided on an idler pulley. In the idler pulley 71, the sealed rolling bearing 100 is fitted on the outer periphery of the shaft 70, and the idler pulley 71 is rotatably supported by the rolling bearing 100.

FIG. 6 shows a cross-sectional view in which a sealed rolling bearing 100 according to the present invention is provided in an alternator 72 which is an electrical accessory. In the alternator 72, a shaft 73 is inserted into a sealed rolling bearing 100 used as an alternator bearing, and a pulley 74 is attached to an end portion of the protruding shaft 73. The pulley 74 is provided with an engagement groove 75 on which a transmission belt (not shown) is hung.

  For this reason, the cage as shown in FIGS. 1 and 3 is also used in the sealed type rolling bearing used in various apparatuses shown in FIGS. Further, the amount of grease filled is set to 65% or more and 80% or less of the static space volume.

  That is, low torque can also be achieved in the sealed rolling bearing used in various devices shown in FIGS. Moreover, the lubricating effect is sufficiently exerted, and the service life (life) can be extended. Incidentally, clutch release bearings, pulley bearings, and electrical accessory bearings are strongly required to prevent grease leakage, reduce torque, and have high dust resistance. Therefore, a bearing like the present invention is optimal.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the cage does not have the groove 21 for the fillet. In the case of configuring the sealed rolling bearing according to the present invention, the number of balls as the rolling elements can be arbitrarily set.

Next, as Example 1, an oil seal groove arrival confirmation test of the encapsulated grease was performed. NTN DF06A74 was used as the bearing, and NA302A (Shin Nippon Oil Co., Ltd.) was used as the grease. The rotational speed was 5500 r / min, the radial load was 1400 N, and the ambient temperature was normal temperature. Further, the static space volume ratio of the amount of grease filled was examined for 80%, 65%, and 59%. The test results are listed in Table 1 below.

  As can be seen from Table 1, when the static space volume ratio of the amount of filled grease is less than 65%, it did not reach the seal groove of grease even when rotated for 24 hours. That is, when the stationary space volume ratio of the amount of grease filled was 80%, the oil content of the grease reached the seal groove one hour after the rotation. When the stationary space volume ratio of the amount of grease filled was 65%, the oil content of the grease reached the seal groove 2 hours after the rotation. From this, it can be seen that the static space volume ratio of the grease filling amount is preferably 65% or more.

Next, as Example 2, a grease leakage confirmation test was performed. NTN DF06A74 was used as the bearing, and NA302A (Shin Nippon Oil Co., Ltd.) was used as the grease. Further, the rotational speed was changed between 600 r / min and 9000 r / min. The radial load was 1400 N and the ambient temperature was room temperature. The operation time was 3 hours. Further, the static space volume ratio of the amount of grease filled was examined for 86%, 83%, and 78%. The test results are listed in Table 2 below.

  As can be seen from Table 2, grease leakage occurs when the static space volume ratio of the grease filling amount is 86%, and grease leakage occurs when the static space volume ratio of the grease filling amount is 83% and 78%. Did not occur. For this reason, it is understood that the static space volume ratio of the amount of grease filled is preferably 83% or less.

Next, as Example 3, a rotational torque measurement test was performed. NTN 6203T2 × 3LLB was used as the bearing, and NA206P (Kyodo Yushi Co., Ltd.) was used as the grease. Moreover, the rotational speed was 1000 r / min, 3000 r / min, and 5000 r / min. The radial load was 100 N, and the ambient temperature was room temperature. Moreover, the amount of grease filled was set to 0.30 g and 0.88 g. In addition, if the grease filling amount is 0.30 g, it is 10% of the total space volume, and if the grease filling amount is 0.30 g, it is 80% of the static space volume. Here, the total space volume refers to the volume obtained by removing the volume of the rolling elements (balls) and the cage from the space volume between the inner ring and the outer ring. The test results are listed in Table 3 below.

  As can be seen from Table 3, it can be said that there is no loss of torque if the static space volume ratio of the grease filling amount is up to 80%.

  From each of the above tests, an appropriate amount of grease to be filled for low torque is 65% or more and 80% or less of the static space volume.

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Ball 4 Cage 5 Seal member 19 Pocket 25 Outer diameter surface 26 Grease retaining groove 30, 31 Chamfer

Claims (14)

The bearing includes an inner ring, an outer ring, a rolling element interposed between the inner ring and the outer ring, and a cage that holds the rolling element. Sealed rolling bearing with grease sealed in the space,
A grease retaining groove for reducing the amount of grease flowing to the rolling surface is provided along the circumferential direction on the outer diameter surface of the cage, and the grease retaining groove communicates with pockets adjacent to each other in the circumferential direction, and the bearing of the cage A sealed-type rolling bearing characterized in that it is positioned closer to the bearing axial pocket opening side than a tangent connecting the bottom of the axial pocket . The sealed rolling bearing according to claim 1, wherein the amount of grease filled is 65% or more and 80% or less of the static space volume . The sealed rolling bearing according to claim 1, wherein the cage is formed by cutting . The sealed rolling bearing according to claim 1 or 2, wherein the cage is formed by injection molding . The sealed rolling bearing according to claim 1 or 2, wherein a material of the cage is a polyamide resin . The sealed rolling bearing according to claim 1 or 2, wherein a material of the cage is a polyether ether ketone resin . The sealed rolling bearing according to claim 1 or 2, wherein a material of the cage is polyphenylene sulfide resin . The sealed rolling bearing according to claim 1 or 2, wherein a material of the cage is a phenol resin . The sealed rolling bearing according to claim 1 or 2, wherein the seal rubber material of the seal member is nitrile rubber . 3. The sealed rolling bearing according to claim 1, wherein the seal rubber material of the seal member is acrylic rubber . The sealed type rolling bearing according to claim 1 or 2, wherein a seal rubber material of the seal member is a fluoro rubber . The sealed rolling bearing according to any one of claims 1 to 11, wherein the sealed rolling bearing is used for a clutch release . The sealed rolling bearing according to claim 1, wherein the sealed rolling bearing is used for a pulley . The sealed rolling bearing according to any one of claims 1 to 11, wherein the sealed rolling bearing is used in an electrical accessory machine .

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